Discussion 2: Evaluating Existing Measures

ARTICLE

Depersonalization, adversity, emotionality, and coping with stressful situations Paula Thomson, PsyD and S. Victoria Jaque, PhD

Department of Kinesiology, California State University, Northridge, California, USA

ABSTRACT Depersonalization is defined as persistent or recurrent episodes of feeling detached or estranged from a sense of self and the world. This study addressed the primary question: Do nonclinical individuals who endorse high symptomatic depersonalization have inherently more intense emotional responses, along with more childhood adversity and past trauma? In this IRB approved study, participants who met clinical levels of depersonalization (n = 43, 16.3%) were compared to a group without clinical levels of depersonalization (n = 221, 83.7%). Adverse childhood experi- ences, adult traumatic events, emotional overexcitability, coping strategies under stress, and anxiety were examined in both groups. The variables to assess depersonalization severity included the Dissociative Experience Scale-II, Cambridge Depersonalization Scale, and Multiscale Dissociation Inventory. The results indicated that clinical levels of depersonalization were identified in 16.3% of the sample. The high depersonaliza- tion group had significantly more adverse childhood experiences, in particular, emotional abuse and neglect. They also experienced more adult traumatic events, higher levels of anxiety, more emo- tional overexcitability, and they employed a less adaptive emo- tion-oriented coping strategy under stress. It is recommended that treating depersonalization symptoms should include exam- ining childhood adversity, especially emotional abuse and neglect. Based on study findings, emotion regulation skills should be promoted to help individuals with elevated depersonalization manage their emotion-oriented coping strategies, anxiety, and emotional overexcitability.

ARTICLE HISTORY Received 3 September Accepted 17 March 2017

KEYWORDS Anxiety; childhood adversity; coping; depersonalization; emotion; trauma

Introduction

Depersonalization (DP) causes significant distress; the symptoms may be transient, persistent, or recurrent, and it is often difficult to fully treat (Mula, Pini, & Cassano, 2007). According to the DSM-5 diagnostic criteria (APA, 2013), individuals with depersonalization disorder (DPD) experience a sense of unreality, detachment, and being an outside observer to their feel- ings, thoughts, sensations, and perceptions, although reality testing remains

CONTACT Paula Thomson, PsyD [email protected] California State University, Northridge, 18111 Nordhoff St., Northridge 91330-8287. Note: Preliminary results presented at 2015 ISSTD Conference

JOURNAL OF TRAUMA & DISSOCIATION 2018, VOL. 19, NO. 2, 143–161 https://doi.org/10.1080/15299732.2017.1329770

© 2017 Taylor & Francis Group, LLC

intact. Time and external surroundings are distorted and the individual often feels sensations such as emotional or physical numbness, foggy, dreamlike, or lifeless. A sense of estrangement from self and the world is often the hallmark of this disorder. Generally, lifetime prevalence for a depersonalization dis- order is approximately 2% (APA, 2013; Michal et al., 2009; Simeon, 2004); however, depersonalization experiences, in themselves, are relatively com- mon, with prevalence rates ranging from 26–74% (Michal et al., 2009). DP operates on a continuum; differentiating between DP and DPD is contingent on degree of impairment, with clinical diagnosis reflecting significant distress (Michal et al., 2009; Mula et al., 2007).

DPD individuals are often self-absorbed and may experience a form of com- pulsive self-scrutiny (Sierra, Baker, Medford, & David, 2005). DPD may operate as an index of severity in other disorders, such as anxiety and depression (APA, 2013; Bob et al., 2008; Lee, Kwok, Hunter, Richards, & David, 2012; Michal et al., 2011; Mula et al., 2007). It can be exacerbated by stress, whether in novel and over- stimulating settings or negative conflict-laden situations (interpersonal, financial, occupational). Physical exhaustion, including lack of sleep, can also exacerbate DP (APA, 2013). DPD individuals also exhibit cognitive difficulties in focusing and retaining information, prolonged absorption, and alexithymia (Simeon, Giesbrecht, Knutelska, Smith, & Smith, 2009). According to the DSM-5 (APA, 2013), behavioral responses of flattened affect and demeanor can be incongruent to the emotional pain that the individual reports.

Childhood interpersonal trauma is a strong predictor of dissociative disorders in general (Simeon, Guralnik, Schmeidler, Sirof, & Knutelska, 2001). Emotional abuse or neglect is strongly associated with depersonalization, along with other stressors such as domestic violence, being parented by a mentally ill family member, or unexpected death of a loved one (Michal et al., 2009; Mula et al., 2007; Simeon et al., 2001). Depersonalization disordered patients also manifest increased physiologic stress responses, even during baseline resting phases (Simeon, Guralnik, Knutelska, Hollander, & Schmeidler, 2001; Simeon, Guralnik, Knutelska, Yehuda, & Schmeidler, 2003). This heightened stress response is further demonstrated in studies that indicate a strong association between heightened anxiety, increased panic attacks, and catastrophic appraisals (Hunter, Phillips, Chalder, Sierra, & David, 2003).

Individuals with elevated DP frequently employ stress-coping strategies such as social isolation, self-blame, and rumination, along with decreased efforts to regulate negative emotions and control stressful situations (Wolfradt & Engelmann, 2003). According to Endler and Parker (1990), there are three primary dispositional coping strategies employed under stress: task-oriented, emotion-oriented, and avoidant-oriented. These three coping strategies are strongly related to personality traits and can be considered traits in and of themselves (Cosway, Endler, Sadler, & Deary, 2000; Deary, Blenkin, Agius, Endler, Zealley, & Wood, 1996; Moos & Holohan, 2003). Task-oriented stress

144 P. THOMSON AND S. V. JAQUE

management is directed toward solving the problem and cognitively restructuring it in an attempt to alter the situation. This is the most effective dispositional strategy (Moos & Holohan, 2003). Emotion-oriented coping strategies suggest that individuals have more emotional reactions that include more self-oriented preoccupation and fantasizing. This approach actually increases stress, is nega- tively related to adaptation and good health, and is associated with more psycho- pathology (Cosway et al., 2000; McWilliams, Cox, & Enns, 2003; Robinaugh & McNally, 2010). Avoidant-oriented stress coping is also considered less adaptive in the long term, because it does not produce change during stress and can be draining over time, although it is generally better than emotional-oriented coping in the short term (Myers, Fleming, Lancman, Perrine, & Lancman, 2013). It is clinically important to understand these three coping strategies and how they manifest in individuals with depersonalization symptoms. Given that DP indivi- duals report a diminished sense of agency, a general sense of disconnectedness from life (APA, 2013), along with blunted autonomic responses (Giesbrecht, Smeets, Merckelbach, & Marko, 2007; Sierra, Senior, Phillips, & David, 2006), suggests that they may also have difficulty coping under stressful situations.

Adding to the difficulties managing stress, DP individuals frequently fluctuate in their emotional reactivity and body sensations, despite report- ing emotional numbing. DPD patients struggle with intense anxiety and constant emotional perseveration; harm avoidant behavior is often engaged to decrease these reactions (Medford, Sierra, Baker, & David, 2005; Mendoza et al., 2011). Whether individuals prone to more DP are also innately more emotionally sensitive and aware is seldom explored, although personality studies suggest that DPD patients are more emotionally reactive (Mendoza et al., 2011; Michal, Wiltink, Till, Wild, Munzel, Blankenberg, & Beutel, 2010)). The overexcitability theoretical model may add insight into how some individuals are vulnerable to heightened DP. Overexcitability is considered an “intense response pattern” to internal or external stimuli (Ackerman, 2009, p. 89; Mendaglio & Tillier, 2006). There are five over- excitability traits: psychomotor, intellectual, sensual, imaginational, and emotional (Ackerman, 2009). Emotional overexcitability (OE-E) is a dis- positional trait that is marked by strong expressions of valuing and finding meaning in relationships, extreme range of feelings, intense affective mem- ory, and greater anxiety (Ackerman, 2009; Falk, Lind, Miller, Piechowski, & Silverman, 1999). It is believed that emotional overexcitability influences how an individual responds to conflict and shapes how they move towards their optimal development (Ackerman, 2006; Mika, 2005). However, excit- ability can also negatively increase the intensity of an experience and the sensitivity to situational stimuli (Alias, Rahman, Majid, & Yassin, 2013; Tieso, 2007). Elevated overexcitability traits often increase difficulty inte- grating into social settings and amplify states of anxiety and depression

JOURNAL OF TRAUMA & DISSOCIATION 145

(Mika, 2005; Sears, Urizar, & Garrett, 2000; Seubert, 2012; Wellisch & Brown, 2013).

Study goals

In this study, differences between individuals with high versus low deperso- nalization were examined. The psychological variables included in this study were based on a desire to further understand coping strategies employed under stressful situations, along with the emotional overexcitability trait. Increased adverse childhood experiences, past traumatic events, and heigh- tened anxiety were included because they are strongly associated with deper- sonalization. To our knowledge, no study has examined all of these psychological constructs together, although preliminary findings from our laboratory were reported at the 2015 International Society for the Study of Trauma and Dissociation conference. We selected a nonclinical sample, in part, to determine if depersonalization is under-reported and under-diag- nosed in the general population. Based on other studies, it is hypothesized that a higher incidence of depersonalization will be found in this population (Hunter, Sierra, & David, 2004). It is believed that clinicians might benefit from the findings in this study, in particular, the relationship between emotional responses and DP.

The study addressed the primary question: Do nonclinical individuals who endorse high symptomatic depersonalization have inherently more intense emotional responses, along with more childhood adversity and past trauma? The first hypothesis is that the DPD group can be identified by higher emotionality (emotional overexcitability trait and coping strategy), anxiety, cumulative exposure to childhood adversity, and cumulative adult traumatic events. The second hypothesis reinforces previous findings (Michal et al., 2009; Mula et al., 2007; Simeon et al., 2001) that the DPD group exhibits a specific pattern of exposure to childhood adversity, in particular, more incidence of neglect compared to the no-DPD group.

Methods

Participants

This Institutional Review Board (IRB) approved cross-sectional study incorpo- rated a community sample of participants (n = 276) who were invited into a larger psychophysiological study that measures the psychological and physiologic effects of stress on healthy individuals. This larger study examines variables such as past trauma, childhood adversity, dissociation, shame, coping strategies, anxiety, depression, PTSD, attachment, trait overexcitability, difficulties with emotional regulation, and capacity to experience positive flow states. Recruitment into the

146 P. THOMSON AND S. V. JAQUE

large psychophysiological study, and this smaller sub-study, included inviting participants from university athletic and arts programs, professional arts training programs offered outside of the university, and word of mouth recruitment in the community. The study was conducted at a large academic institution that is located in a major city with strong athletic and arts programing. There were no restrictions for gender, race, or ethnicity.

There were 75 (27.3%) male participants and 200 (72.7%) female participants (1 missing data); mean age was 23.63 (sd = 5.45). In this investigation, we divided the sample into two groups. The groups were developed based on clinical cut off scores on at least one of three depersonalization self-report scales (Dissociative Experience Scale—II depersonalization subscale ≥30, Cambridge Depersonalization Scale ≥70, and Multiscale Dissociation Inventory ≥20). In the MANCOVA calculations, the sample size decreased to a total of 264 partici- pants. This decrease occurred due to incomplete data from several of the participants. There were 221 (83.7%) participants who scored below the clinical cutoff score for DPD and 43 (16.3%) who scored within the clinical range.

Measurements

Adverse Childhood Experiences (ACE): The ACE is a dichotomous 10 item self- report instrument that assesses categories of childhood abuse, neglect, and house- hold dysfunction (Felitti & Anda, 2010). A total score of yes responses are derived, regardless of frequency or intensity. The abuse category probes for emotional, physical, and sexual abuse; the neglect category probes for emotional and physical neglect. The household dysfunction category includes mother treated violently, substance abuse, parental separation or divorce, household member imprisoned, or suffering a mental illness. For the purposes of this study, three subscales were also calculated based on aggregate scores: (1) abuse (emotional, physical, sexual), (2) neglect (emotional, physical), and (3) family dysfunction (domestic violence, substance abuse, separation/divorce, mental illness, imprisonment). In this study, the test–retest reliability calculation for the ACE was stable (r = .86, p < .01). The test–retest process was based on a second round of testing that occurred 6 months after the initial data collection.

Beck Anxiety Inventory (BAI-II): The BAI-II (Beck, Epstein, Brown, & Steer, 1988) assesses the severity of patient anxiety. It is a self-report, 21 item instrument that measures how much the respondent was bothered by the symptom in the past week, ranging from 0 (not at all) to 3 (severely). Each item is descriptive of subjective, somatic, or panic-related symptoms of anxiety. The BAI-II is appropriate for individuals between the ages of 13–80 years, requiring approximately 5 minutes to administer. The summed score is then ranked: 0–7 (minimal level of anxiety), 8–15 (mild anxiety), with 2 clinical ranges that include 16–25 (moderate anxiety), and 26–63 (severe anxiety). Unlike the State-Trait Anxiety Inventory (STAI-Y) (Spielberger,

JOURNAL OF TRAUMA & DISSOCIATION 147

1983) that is highly confounded with measures of depression (Fydrich, Dowdall, & Chambless, 1992), the BAI-II’s strongest quality is its ability to assess panic symptomatology such as trembling, difficulty breathing, numb- ness or tingling, heart racing, dizziness or lightheadedness, and fears of losing control, dying or the worst happening (de Ayala, Vonderharr-Carlson, & Kim, 2005; Leyfer, Ruberg, & Woodruff-Borden, 2006). The BAI-II has excellent internal consistency reliability (α = .92) and high test–retest relia- bility (r = .75) (Beck & Steer, 1990). In this study, the Cronbach’s alpha for the BAI-II was α of .91.

Coping Inventory for Stressful Situations (CISS): The CISS (Endler & Parker, 1990) is a 48 item 5 point Likert scale that measures three main coping strategies: task-oriented focus (dealing with the problem at hand), emotion-oriented focus (concentrating on the resultant emotions), and avoidance-oriented coping (trying to avoid the problem). In each coping strategy scale, there are 16 items. The Likert scale ranges from 1 (not at all) to 5 (very much) and the questions ask participants to indicate how much they engage in various coping activities during a stressful situation. The CISS has stable factor structure, excellent internal validity, adequate test–retest reliability, and good construct validity (Cosway et al., 2000; Endler & Parker, 1990; McWilliams et al., 2003). In this study, Cronbach’s alpha for task- oriented focus was α of.86, emotion-oriented focus was αof.89, and avoidance was α of .87.

Overexcitability Questionnaire-II (OEQ-II): The OEQ-II (Falk et al., 1999) is a 50 item measurement used to assess the five forms of over- excitability (OE). Each OE subscale (psychomotor, sensual, imaginational, intellectual, emotional) consists of ten 5-point Likert items ranging from 1 (not at all) to 5 (very much like me). Mean scores are derived for each scale. There is an indication that gender differences exist in this measure (Bouchet & Falk, 2001; Miller, Falk, & Huang, 2009), with women scoring higher on emotional and sensual OE; whereas, men score higher on intel- lectual and psychomotor OEs (van den Broeck, Hofmans, Cooremans, & Staels, 2014). The OEQ-II has high internal reliability and internal consis- tency and good content validity. Because this study examined the relation- ship between emotion and DP, we only included the emotional overexcitability scale. The Cronbach’s alpha score for emotional overexcit- ability was excellent (α = .85).

Traumatic Events Questionnaire (TEQ): The TEQ (Lauterbach & Vrana, 2001) is a self-report 11 item dichotomously scored instrument that assesses exposure to nine different traumatic events (accidents, natural disasters, crime, child abuse, rape, adult abusive experiences, witnessing death/mutila- tion of someone, being in a dangerous/life-threatening situation, and receiv- ing news of an unexpected death of a loved one). The final two items probe for any other traumatic event not listed and for traumatic event(s) that were too difficult to discuss with anyone. Since calculating the internal consistency

148 P. THOMSON AND S. V. JAQUE

of the TEQ was inappropriate a test–retest calculation was conducted: The TEQ in this study was stable (r = .75, p < .01). The test–retest process was based on a second round of testing that occurred 6 months after the initial data collection.

Depersonalization testing measurements Cambridge Depersonalization Scale (CDS): The CDS (Sierra & Berrios, 2000) contains 29 items, each with a Likert scale for frequency and duration. The scale was designed to measure the sum of frequency and duration; it addresses the fluctuating and intermittent symptomatology of depersonalization. The global score is the aggregate score of both the frequency and duration scales, with a cut off score of ≥70 indicting a depersonalization disorder. The items probe for abnormal experiences during the past 6 months that affect different sensory modalities, inability to experience a range of different emotions, heightened self-awareness with a simultaneous feeling of a lack of body own- ership and agency. Cognitive components include thoughts of feeling empty, changes in personal memory recall, inability to evoke images, and distortions of time and space experiences. The CDS has high internal consistency and reliability. In this study, Cronbach’s alpha was α = .96.

Dissociative Experience Scale—II (DES-II): The DES-II (Carlson et al., 1993; Waller, Putnam, & Carlson, 1996) is a 28 item self-report instrument that asks subjects to indicate the frequency of dissociative experiences in their daily life. Persons who are administered the DES-II are asked to endorse experiences that are not related to situations when the subject is under the influence of alcohol or drugs. Each item is given a score between 0 (never) to 100 (always), and a mean total score is calculated. The DES-II and its sub- scales have very high internal consistency scores (Van Ijzendoorn & Schuengel, 1996). In this study, we included the depersonalization /derealiza- tion subscale (DES-Dep/Der) (6 items: 7, 11, 12, 13, 27, 28) (Carlson & Putnam, 1992) with an α = .85. To determine clinical levels of depersonaliza- tion, a cutoff score was established (≥30) (Waller et al., 1996). For descriptive purposes, a DES-II taxon group was defined based on scores ≥20 on the taxon scale (8 items: 3, 5,7, 8, 12, 13, 22, 27) (Waller et al., 1996) with an α = .82. This was calculated to determine shared distribution patterns for individuals in both the DPD and taxon groups.

Multiscale Dissociation Inventory (MDI): This 30 item Likert self-report scale (1 = never to 5 = very often) measures the frequency of dissociative symptoms during the past month (Briere, 2002). The MDI provides a total dissociation score, along with six subscales that measure disengagement, depersonalization, derealization, emotional constriction, memory distur- bances, and identity dissociation. The test yields raw scores that can be converted to T-scores to determine clinically significant levels of each type of dissociation. The raw clinical cutoff score for depersonalization is ≥9, and

JOURNAL OF TRAUMA & DISSOCIATION 149

for derealization, it is ≥11. It has excellent validity and reliability. In this study, in an effort to match the DP items listed in the DES-II and CDS, we merged the depersonalization and derealization scale (raw clinical cut off score ≥20) (Briere, Weathers, & Runtz, 2005). Cronbach’s alpha for the depersonalization/derealization scale was excellent (α = .88).

The three depersonalization measurements provide valuable information about the nature and severity of symptoms; however, each self-report instru- ment assesses a different time period. The DES-II measures daily life, the CDS time range is for a six-month period, and the MDI evaluates symptoms experienced during the past month. When determining individuals in the clinical cut off range, the DES-II captured 53.1% of the sample, the CDS identified 31.3% of the sample, and the MDI dep/der scale determined 93.1% of the sample. These differences may be due to the three different time periods being assessed. Of note, approximately 25% of the DPD individuals were identified by all three measures; however, the majority was collectively identified by both the DES-II and the MDI.

Procedure and analysis

Participants who were accepted into the study completed an informed consent, followed by a package of self-report measures. They completed these forms in a laboratory or studio setting. The majority of participants returned 6 months later to complete a second package. A smaller randomly selected sample participated in physiological testing that measured heart rate variability while performing under stressful conditions (not reported in this study). SPSS version 22.0 was used for all statistical analyses. First, descriptive statistical analyses were conducted. Participants were assigned to the depersonalization (DPD) group if they scored ≥ the cutoff scores designated in one of the three depersonalization measures: (1) ≥30 on the DES-II depersonalization subscale, (2) ≥70 on the CDS, or (3) ≥20 on the MDI dep/der combined scale. Those who did not reach the clinical cutoff scores on any of these measures were placed in the no-depersonalization disorder group (no-DPD). To analyze group differences, multivariate analyses of covar- iance (MANCOVA) were conducted (with age and gender as the covariates). The first MANCOVA was calculated to examine whether there were significant between group effects for cumulative childhood adverse experiences, cumulative traumatic events, anxiety, emotional overexcitability, and coping strategies (task, emotion, avoidant). A second MANCOVA (age and gender as covariates) was calculated to address the second hypothesis related to the specific nature of adverse childhood exposure. In the second MANCOVA, group differences were examined for the following adverse childhood experiences: family dysfunction, abuse, and neglect. Gender and age were included as covariates in both MANCOVA calcula- tions to account for any effects of gender and age on these variables. These were included based on studies that demonstrated more females experience DP

150 P. THOMSON AND S. V. JAQUE

(Aberibigbe, Bloch, & Walker, 2001; Medford et al., 2005) and that DP decreases with age (Michal et al., 2009). We also wanted to account for the fact that there were more women in the sample. In the MANCOVA analyses, Bonferroni alpha (.05) corrections were used to determine the nature of the differences between the group means.

Results

Descriptive statistics

The descriptive statistics include demographic distribution (gender, age, ethnicity, and DES-II taxon distribution). The distribution pattern demonstrates that more individuals placed in the DPD group experienced dissociative taxon membership (cut off score of ≥20 on the taxon subscale). This finding suggests that 59.2% of the DPD group may have more dissociative pathology beyond DPD. Gender differ- ences were minimal in the DPD group with 46.9% males and 53.1% females. The ethnicity distribution was similar for both the no-DPD and DPD groups for both African andLatino groups; however, there were moreAsians and fewer Caucasians in the DPD group compared to the no-DPD groups. See Table 1 for details. Distribution patterns for each ACE item were also calculated for both groups; the DPD group endorsed more ACE experiences. The highest distribution pattern was evident in emotional abuse (39.5%), followed by emotional neglect (30.2%) and divorce/separation (30.2%). Two other ACE items, physical abuse (27.9%) and family mental illness (27.9%), were also elevated in the DPD group. See Table 2 for details.

Depersonalization related differences

Hypothesis One: The DPD group will be identified by higher emotionality (trait and coping strategy), anxiety, cumulative exposure to childhood adversity, and cumulative adult traumatic events. This hypothesis was examined by comparing

Table 1. Descriptive Statistics and Percentages for Demographic Information. No-DPD DPD

n = 221 n = 43

Gender: Males 62 (24.2%) 23 (46.9%) Females 194 (75.8%) 26 (53.1%) Ethnicity: African 27 (11.8%) 6 (14.3%) Asian 38 (16.7%) 14 (33.3%) Caucasian 12.1 (53.1%) 15 (35.7%) Latino 42 (18.4%) 7 (16.7%) DES-II Taxon 14 (5.5%) 29 (59.2%) Age 23.66 (sd = 5.20) 23.47 (sd = 6.65)

Note: DES-II Taxon = dissociative experience scale—II discriminating pathological subscale

JOURNAL OF TRAUMA & DISSOCIATION 151

group differences for mean score variables: task-oriented coping, emotion- oriented coping, avoidant-oriented coping, emotional overexcitability, anxiety, total ACE, and total traumatic experiences. In the first MANCOVA (with gender and age as covariates), group differences between no-DPD and DPD groups were calculated. The MANCOVA demonstrated that significant main effects (Wilks’s Λ = .854, F(7, 254) = 6.220, p = .000, η2 = .146). Age (p = .005) and gender (p = .000) were significant covariates in this calculation. In the pairwise comparisons between the no-DPD and DPD groups, there were significant differences, specifically significantly higher scores in the DPD group for OEQ emotionality (p = .005), CISS emotional coping (p < .001), anxiety (p < .001), cumulative ACEs (p = .005), and cumulative adult traumatic events (p = .004). There were no group differences for the variables CISS task-oriented coping (p = .188) and avoidant coping (p = .147). These findings demonstrate that gender and age were cofounding variables; in particular, younger age and female gender were significant variables in the DPD group. Also trait emotionality, emotional coping strategies and anxiety

Table 2. Descriptive Percentage Statistics for Adverse Childhood Experience Items.

No-DPD DPD

n = 221 n = 43

ACE #1 Abuse—Emotional 26.4% 39.5% ACE #2 Abuse—Physical 14.7% 27.9% ACE #3 Abuse—Sexual 10.0% 9.3% ACE #4 Neglect—Emotional 14.7% 30.2% ACE #5 Neglect—Physical 2.2% 4.7% ACE #6 Family Dysfunction—Separated/Divorced 28.1% 30.2% ACE #7 Family Dysfunction—Domestic Violence 8.7% 18.6% ACE #8 Family Dysfunction—Addiction 14.3% 20.9% ACE #9 Family Dysfunction—Mental Illness 16.5% 27.9% ACE #10 Family Dysfunction—Prison 5.2% 11.6%

Note: ACE = adverse childhood experiences

Table 3. Mean Descriptive Statistics and Standard Deviation (SD) for Psychological Variables. No-DPD DPD

n = 221 n = 43

ACE 1.43 (1.86) 2.21 (2.37)** TEQ 1.86 (1.90) 2.91 (2.51)** BAI-II 8.21 (7.64) 14.53 (11.51)*** OE-E 3.56 (.72) 3.78 (.83)** CISS-task 59.00 (11.63) 56.02 (11.84) CISS-emotion 42.84 (11.93) 51.70 (10.68)*** CISS-avoid 50.26 (12.04) 53.16 (12.01)

Note: ACE = adverse childhood experiences, TEQ = traumatic event questionnaire, BAI-II = Beck anxiety inventory, OE-E = overexcitability-emotional, CISS-task = coping with stressful situations: Task-oriented, CISS-emotion = coping with stressful situations: Emotion-oriented, CISS-avoid = coping with stressful situations: Avoidant-oriented

MANCOVA (age and gender covariates) comparison of mean scores showing significant group differences between high depersonalization (DPD) and low depersonalization (No-DPD) groups.

** p < .01. ***p < .001

152 P. THOMSON AND S. V. JAQUE

were elevated in the DPD group. Similar to previous findings (Michal et al., 2009; Mula et al., 2007; Simeon et al., 2001), the DPD group also had more exposure to childhood adversity and adult traumatic events. See Table 3 for MANCOVA results and group mean scores.

Hypothesis Two: The DPD group exhibits a specific pattern of exposure to childhood adversity, in particular, more incidence of neglect compared to the no-DPD group. Although cumulative ACEs were examined in the first MANCOVA analysis, the second MANCOVA (age and gender as covariates) was calculated to answer the specific nature of childhood exposure. This hypothesis was supported: Group differences between no-DPD and DPD groups were significant for the variables childhood family dysfunction, child- hood abuse, and childhood neglect (Wilks’s Λ = .965, F(3, 263) = 3.174, p = .025, η2 = .035). The pairwise comparison demonstrated greater family dysfunction (p = .024) and childhood abuse (p = .027) in the DPD group compared to the no-DPD group. An even stronger significant difference was found for childhood neglect, with higher incidence in the DPD group (p = .005). There were no significant influences of age (p = .221) and gender (p = .170) in this calculation. These results reflect similar findings by Simeon et al. (2001), in particular, a strong association between DPD and emotional and physical neglect. See Table 4 for details.

Discussion

Similar to previous research findings, the group with elevated depersonaliza- tion symptoms had significantly greater childhood adversity experiences, including family dysfunction, abuse, and neglect. This finding supports previous research that demonstrated an association between depersonaliza- tion disorder and childhood trauma (Michal et al., 2007), and more specifi- cally, emotional and physical neglect (Simeon et al., 2001). In the current study, the high depersonalization group experienced significantly more

Table 4. Mean Descriptive Statistics and Standard Deviations (SD) for Adverse Childhood Experiences Variables.

No-DPD DPD

n = 221 n = 43

ACE—Family Dysfunction .72 (1.05) 1.09 (1.38)* ACE—Abuse .51 (.86) .77 (.92)* ACE—Neglect .17 (.41) .35 (.53)**

Note: ACE = adverse childhood experiences MANCOVA (age and gender covariates) comparison of mean scores showing significant group differences between high depersonalization (DPD) and low depersonalization (No- DPD) groups.

*p < .05. **p < .01.

JOURNAL OF TRAUMA & DISSOCIATION 153

neglect compared to the low DP group. A significant proportion also experi- enced emotional abuse, emotional neglect, physical abuse, family member with a mental illness, and more separation/divorce. These specific adverse childhood experiences can compromise adaptive developmental maturation, such as the capacity to engage in mindfulness. Mindful activities promote attentional processes and heighten somatic sensations, all factors that are essential to encode strong autobiographical memories (Michal et al., 2007). Further, without optimal attachment-related experiences, children may detach from a sense of self and the world; they do not enjoy paying attention to a present-moment experience, especially if they are repeatedly subjected to the absence of a caregiving figure or they encounter emotional and /or physical abuse (Michal et al., 2007).

In this study, the group with elevated DP also experienced more past traumatic events in adulthood. Studies have demonstrated that past trauma alters cognitive schemas, as well as intensifying dissociative processing (Wright, Crawford, & Del Castillo, 2009). A substantial proportion of the study (16.3%) scored above the cutoff threshold for a depersonalization disorder, a much higher distribution rate of individuals manifesting symp- toms of depersonalization compared to the typical distribution reported in the general population (2%) (APA, 2013; Michal et al., 2009; Simeon, 2004). This distribution pattern lends support to claims by Hunter et al. (2004) that depersonalization disorders are under-reported and under-diagnosed. Because this is a correlational study, no cause and effect statements are possible; however, the strong association between cumulative childhood adversity and adult trauma, coupled with an emotional overexcitability trait, may account for more DP experiences in the high scoring DPD group. Because DP operates on a continuum, it is important to note that individuals in the no-DPD group also endorsed DP experiences; however, these experiences were much fewer and less intense.

As reported in earlier studies (APA, 2013; Bob et al., 2008; Mula et al., 2007; Simeon, 2004), the DPD group in this study had greater anxiety (mean score near clinical cut off) compared to the no-DPD group. Beyond reporting higher levels of anxiety, the DPD group had significantly higher trait-like emotional overexcitability. They also employed more emotion-oriented coping under stressful situations, a strategy that is deemed less adaptive (Endler & Parker, 1990, 1994). Although individuals with depersonalization disorder claim that they are detached from their sense of self and their emotions, in this study, they endorsed greater emotion-oriented coping strategies and more emotional over- excitability responses. Stressful conditions, such as novel or over-stimulating settings, may further intensify their depersonalization symptoms (APA, 2013). According to Michal et al. (2011), these dispositional traits, accompanied by elevated anxiety, suggest that individuals with clinical levels of DP may have greater difficulty under stress. Despite these differences, in this study, the DPD

154 P. THOMSON AND S. V. JAQUE

group resembled the no-DPD group for task-oriented and avoidant-oriented coping. In this nonclinical sample, despite more emotional-oriented coping strategies, the DPD participants were able to employ other coping strategies as well. Perhaps for the DPD group, engaging in these more effective coping strategies buffered the negative effects of their heightened DP symptoms and bias toward emotionality. In order to counter the negative effects of heightened emotionality, this high DP group may need to employ even more task-oriented strategies to offset their emotional tendencies.

Given the study findings, clinical recommendations include helping DPD individuals shift from more passive coping behavior (avoidant, self-blame, perseveration, isolation) to more task-oriented strategies while under stress- ful situations (Wolfradt & Engelman, 2003). This, along with other effective emotion regulating skills (self-compassion, somatic-based grounding techni- ques, cognitive-behavioral skills), may decrease the frequency and intensity of depersonalization episodes. Based on the results in this study, the partici- pants with clinical levels of depersonalization manifested increased emotional overexcitability to internal and external stimuli. Their emotional orientation reflects previous findings that indicate individuals with depersonalization disorder tend to misinterpret situations as catastrophic (Hunter et al., 2003) and suffer disruptions in self-awareness (Sierra & David, 2011). Further, neurobiological studies have demonstrated that DPD individuals process emotion-laden content differently, with some indication that these individuals are both oriented toward aversive stimuli and actively suppres- sing their responses (Medford et al., 2006). Helping them regulates that these responses may diminish their need to blunt emotional experiences.

Clinically addressing depersonalization, along with the associated past trauma and childhood adversity (in particular, neglect and emotional abuse), should adhere to evidence-based traumatology practices such as cognitive- behavioral therapy (Medford et al., 2005). Clinical treatment should also address depersonalization as a separate disorder, although 60% of the DPD individuals in this sample also had elevated scores on the dissociative taxon, a measurement that identifies other dissociative pathology. Following previous recommendations, a proportion of DPD individuals did not meet the criteria for other dissociative disorders, and consequently, clinical attention should be directed toward differentiating the nature of dissociation and the specific needs related to treating depersonalization (Simeon, Knutelska, Nelson, Guralnik, & Schmeidler, 2003). Clinical attention should also be directed toward elevated anxiety, panic, and depression (Michal et al., 2011; Wolfradt & Engelman, 1999). This study adds to the literature that demonstrates an association between depersonalization and anxiety, a result that reinforces the need to clinically address both depersonalization and anxiety (Lee et al., 2012). Related to elevated anxiety in individuals with clinical levels of depersonalization, increased reporting of somatic symptoms of dizziness and vertigo should be

JOURNAL OF TRAUMA & DISSOCIATION 155

addressed (Tschan, Wiltnik, Adler, Beutel, & Michal, 2013). Other organic disorders such as epilepsy, migraines, traumatic brain injury, and cerebrovas- cular disease are also associated with depersonalization. Treating depersonali- zation may require the inclusion of these other organic disorders, especially because they can lead to physical impairment (Lambert, Sierra, Phillips, & David, 2002).

Some of the limitations in this study include the inherent bias found in self-report measures. The distribution between men and women was very uneven, a pattern that can affect the results on the overexcitability scale (Warne, 2011). To address this limitation, gender was included as a covariate. To account for the difficulty diagnosing depersonalization disorder, espe- cially diagnosing based on self-report screening measures, this study included the three leading depersonalization instruments (DES-II depersonalization /derealization scale, Cambridge Depersonalization Scale, and the Multiscale Dissociation Inventory—Depersonalization /Derealization). These three scales have excellent psychometric values (Blevins, Weathers, & Mason, 2012), and in this study, they were regarded as highly reliable; however, they may not accurately identify all individuals with clinical levels of deper- sonalization. These three measures also differ in the time period that is examined; a limiting factor that further compromises effective assessment. Without a clinical interview, it is difficult to determine whether all indivi- duals placed in the DPD group were actually experiencing clinical levels of DPD. Future studies should address this problem; however, when examining a nonclinical population, this limitation is often present. Another limitation is the decision to include only the emotional overexcitability (OE) factor; the other four OEs may offer further insight about individuals who experience high DP symptoms; however, the intention of this study was to examine emotional responses (coping strategies and anxiety), along with childhood adversity and past traumatic events. Lastly, future studies should include pain severity, genetic factors, and substance use. Previous findings demonstrate that DPD symptoms are related to chronic or intense pain (Aberibigbe et al., 2001), sometimes induced by illicit drug use (Medford et al., 2005; Simeon, 2004), as well as a strong association with genetic vulnerability (APA, 2013).

To conclude, the findings in this study suggest that clinical levels of depersonalization may be higher in a nonclinical sample than the 2% that is generally reported (Lee et al., 2012; Simeon, 2004). Like the studies conducted by Aponte-Soto and colleagues (2014) and Michal and colleagues (2009), our study found that 16.3% of the participants endorsed symptoms that met the criteria for a depersonalization disorder. Although depersona- lization includes a subjective experience of emotional numbing (APA, 2013; Sierra et al., 2005; Simeon et al., 2000), the findings in this study support previous studies, suggesting that individuals with elevated depersonalization may be paradoxically more emotionally distressed.

156 P. THOMSON AND S. V. JAQUE

References

Aberibigbe, Y. A., Bloch, R. M., & Walker, W. R. (2001). Prevalence of depersonalization and derealization experiences in a rural population. Psychiatry and Psychiatric Epidemiology, 36, 63–69. doi:10.1007/s001270050291

Ackerman, C. M. (2009). The essential elements of Dabrowski’s theory of positive disintegra- tion and how they are connected. Roeper Review, 31 (2), 81–95. doi:10.1080/ 02783190902737657

Alias, A., Rahman, S., Majid, R. A., & Yassin, S. F. M. (2013). Dabrowski’s overexcitabilities profile among gifted students. Asian Social Science, 9 (16), 120–125. doi:10.5539/ass. v9n16p120

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental dis- orders (5th ed.). Washington, DC: American Psychiatric Publishing.

Aponte-Soto, M. R., Velez-Patrana, M., Martinez-Taboas, A., & Gonzalez, R. A. (2014). Psychometric properties of the Cambridge depersonalization scale in Puerto Rico. Journal of Trauma and Dissociation, 15, 348–363. doi:10.1080/15299732.2013.856370

Beck, A. T., Epstein, N., Brown, G., & Steer, R. A. (1988). An inventory for measuring clinical anxiety: Psychometric properties. Journal of Consulting and Clinical Psychology, 56, 893– 897. doi:10.1037/0022-006X.56.6.893

Beck, A. T., & Steer, R. A. (1990). Manual for the beck anxiety inventory. San Antonio, TX: Psychological Corporation.

Blevins, C. A., Weathers, F. W., & Mason, E. A. (2012). Construct validity of three deperso- nalization measures in trauma-exposed college students. Journal of Trauma and Dissociation, 13 (5), 539–553. doi:10.1080/15299732.2012.678470

Bob, P., Fedor-Freybergh, P., Jasova, D., Bizik, G., Susta, M., Pavlat, J., . . . Raboch, J. (2008). Dissociative symptoms and neuroendocrine dysregulation in depression. Medical Science Monitor, 14 (10), CR499– 504.

Bouchet, N., & Falk, R. F. (2001). The relationship among giftedness, gender, and over- excitability. Gifted Child Quarterly, 45 (4), 260–267. doi:10.1177/001698620104500404

Briere, J. (2002). Multiscale dissociation inventory professional manual. Odessa, Florida: Psychological Assessment Resources.

Briere, J., Weathers, F. W., & Runtz, M. (2005). Is dissociation a multidimensional construct? Data from the multiscale dissociation inventory. Journal of Traumatic Stress, 18 (3), 221– 231. doi:10.1002/(ISSN)1573-6598

Carlson, E. B., & Putnam, F. W. (1992). Manual for the Dissociative Experiences Scale (Unpublished psychological manual). Beloit College, Wisconsin.

Carlson, E. B., Putnam, F. W., Ross, C. A., Torem, M., Coons, P., Dill, D. L., . . . Braun, B. G. (1993). Validity of the dissociative experiences scale in screening for multiple personality disorder: A multicenter study. American Journal of Psychiatry, 150, 1030–1036. doi:10.1176/ajp.150.7.1030

Cosway, R., Endler, N. S., Sadler, A. J., & Deary, I. J. (2000). The coping inventory for stressful situations: Factorial structure and associations with personality traits and psycho- logical health. Journal of Applied Biobehavioral Research, 5 (2), 121–143. doi:10.1111/ jabr.2000.5.issue-2

Deary, I.J. 1., Blenkin, H., Agius, R.M., Endler, N.S., Zealley, H., & Wood, R. (1996).Models of job-related stress and personal achievement among consultant doctors. British Journal of Psychology, 87(Pt 1), 3–29.

de Ayala, R. J., Vonderharr-Carlson, D. J., & Kim, D. (2005). Assessing the reliability of the Beck Anxiety Inventory scores. Educational and Psychological Measurements, 65, 742–756. doi:10.1177/0013164405278557

JOURNAL OF TRAUMA & DISSOCIATION 157

Endler, N. S., & Parker, J. D. A. (1990). Coping inventory for stressful situations: Manual (2nd ed.). Toronto, CAN: Multi-Health Systems.

Endler, N. S., & Parker, J. D. A. (1994). Assessment of multidimensional coping: Task, emotion, and avoidance strategies. Psychological Assessment, 6, 50–60. doi:10.1037/1040- 3590.6.1.50

Falk, R. F., Lind, S., Miller, N. B., Piechowski, M. M., & Silverman, L. K. (1999). The overexcitability questionnaire – two (OEQII): Manual scoring system and questionnaire. Denver, CO: Institute for the Study of Advanced Development.

Felitti, V. J., & Anda, R. F. (2010). The relationship of adverse childhood experiences to adult medical disease, psychiatric disorders and sexual behavior: Implications for healthcare. In R. A. Lanius, E. Vermetten, & C. Pain (Eds.), The impact of early life trauma on health and disease: The hidden epidemic (pp. 77–87). Cambridge, UK: Cambridge University Press.

Fydrich, T., Dowdall, D., & Chambless, D. L. (1992). Reliability and validity of the beck anxiety inventory. Journal of Anxiety Disorders, 6 (1), 55–61. doi:10.1016/0887-6185(92) 90026-4

Giesbrecht, T., Smeets, T., Merckelbach, H., & Marko, J. (2007). Depersonalization experi- ences in undergraduates are related to heightened stress cortisol responses. Journal of Nervous and Mental Disease, 195 (4), 282–287. doi:10.1097/01.nmd.0000253833.60618.60

Hunter, E. C. M., Phillips, M. L., Chalder, T., Sierra, M., & David, A. S. (2003). Depersonalization disorder: A cognitive-behavioural conceptualization. Behaviour Research and Therapy, 41, 1451–1467. doi:10.1016/S0005-7967(03)00066-4

Hunter, E. C. M., Sierra, M., & David, S. A. (2004). The epidemiology of depersonalization and derealization: A systematic review. Psychiatry and Psychiatric Epidemiology, 39, 9–18. doi:10.1007/s00127-004-0701-4

Lambert, M. V., Sierra, M., Phillips, M. L., & David, A. S. (2002). The spectrum of organic depersonalization: A review plus four cases. The Journal of Neuropsychiatry and Clinical Neurosciences, 14, 141–154. doi:10.1176/jnp.14.2.141

Lauterbach, D., & Vrana, S. (2001). The relationship among personality variables, exposure to traumatic events and severity of posttraumatic stress symptoms. Journal of Traumatic Stress, 14, 29–38. doi:10.1023/A:1007831430706

Lee, W. E., Kwok, C. H. T., Hunter, E. C. M., Richards, M., & David, A. S. (2012). Prevalence and childhood antecedents of depersonalization syndrome in a UK birth cohort. Social Psychiatry and Psychiatric Epidemiology, 47, 253–261. doi:10.1007/s00127-010-0327-7

Leyfer, O. T., Ruberg, J. L., & Woodruff-Borden, J. (2006). Examination of the utility of the Beck Anxiety Inventory and its factors as a screener for anxiety disorder. Anxiety Disorders, 20, 444–458. doi:10.1016/j.janxdis.2005.05.004

McWilliams, L. A., Cox, B. J., & Enns, M. (2003). Use of the coping inventory for stressful situations in a clinically depressed sample: Factor structure, personality correlates and prediction of distress. Journal of Clinical Psychology, 59 (4), 423–437. doi:10.1002/ jclp.10080

Medford, N., Brierley, B., Brammer, M., Bullmore, E. T., David, A. S., & Phillips, M. L. (2006). Emotional memory in depersonalization disorder: A functional MRI study. Psychiatry Research: Neuroimaging, 148, 93–102. doi:10.1016/j.pscychresns.2006.05.007

Medford, N., Sierra, M., Baker, D., & David, A. S. (2005). Understanding and treating depersonalisation disorder. Advances in Psychiatric Treatment, 11, 92–100. doi:10.1192/ apt.11.2.92

Mendaglio, S., & Tillier, W. (2006). Dabrowski’s theory of positive disintegration and giftedness: Overexcitability research findings. Journal for the Education of the Gifted, 30 (1), 68–87. doi:10.1177/016235320603000104

158 P. THOMSON AND S. V. JAQUE

Mendoza, L., Navines, R., Crippa, J. A., Fagundo, A. B., Guitierrez, F., Nardi, A. E., . . . Martin-Santos, R. (2011). Depersonalization and personality in panic disorder. Comprehensive Psychiatry, 52, 413–419. doi:10.1016/j.comppsych.2010.09.002

Michal, M., Beutel, M. E., Jochen, J., Zimmermann, M., Wolters, S., & Heidenreich, T. (2007). Depersonalization, mindfulness, and childhood trauma. Journal of Nervous and Mental Disease, 195 (8), 693–696. doi:10.1097/NMD.obo13e31811f4492

Michal, M., Glaesmer, H., Zwerenz, R., Knebel, A., Wiltink, J., Brahler, E., & Beutel, M. E. (2011). Base rates for depersonalization according to the 2-item version of the Cambridge Depersonalization Scale (CDS-2) and its associations with depression /anxiety in the general population. Journal of Affective Disorders, 128, 106–111. doi:10.1016/j. jad.2010.06.033

Michal, M., Wiltink, J., Subic-Wrana, C., Zwerenz, R., Tuin, I., Lichy, M., Beutel, M. E. (2009). Prevalence, correlates, and predictors of depersonalization experiences in the German general population. The Journal of Nervous and Mental Disease, 197 (7), 499– 506. doi:10.1097/NMD.06013e3181aacd94

Michal, M., Wiltink, J., Till, Y., Blankenberg, S., & Beutel, M. E. (2010). Type D personality and depersonalization are associated with suicidal ideation in the German general popula- tion aged 35–74: Results from the Gutenberg Heart Study. Journal of Affective Disorders, 125, 227–233. doi:10.1016/j.jad.2010.02.108

Michal, M., Wiltink, J., Till, Y., Wild, P. S., Blankenberg, S., & Beutel, M. E. (2011). Distinctiveness and overlap of depersonalization with anxiety and depression in a community sample: Results from the Gutenberg Heart Study. Psychiatry Research, 188, 264–268. doi:10.1016/j. psychres.2010.11.004

Mika, E. (2005). Theory of Positive Disintegration as a model of personality development for exceptional individuals. In N. L. Hafenstein, B. Kutrumbos, & J. Delisle (Eds.), Perspectives in gifted education: Complexities of emotional development, spirituality and hope (Vol. 3, pp. 4–32). Denver, CO: Publication Institute for the Development of Gifted Education, Ricks Center for Gifted Children.

Miller, N. B., Falk, F., & Huang, Y. (2009). Gender identity and the overexcitability profiles of gifted college students. Roeper Review, 31, 161–169. doi:10.1080/02783190902993920

Moos, R. H., & Holohan, C. J. (2003). Dispositional and contextual perspectives on coping: Toward an integrative framework. Journal of Clinical Psychology, 59 (12), 1387–1402. doi:10.1002/jclp.10229

Mula, M., Pini, S., & Cassano, G. B. (2007). The neurobiology and clinical significance of depersonalization in mood and anxiety disorders: A critical reappraisal. Journal of Affective Disorders, 99, 91–99. doi:10.1016/j.jad.2006.08.025

Myers, L., Fleming, M., Lancman, M., Perrine, K., & Lancman, M. (2013). Seizure, 22, 634–639. doi:10.1016/j.seizure.2013.04.018

Robinaugh, D.J., & McNally, R.J. (2010). Autobiographical memory for shame and guilt provoking events: Association with psychological symptoms.” Behavior Research and Therapy, 48(7),646–652.

Sears, S. F., Urizar, G. G., & Evans, G. D. (2000). Examining a stress-coping model of burnout and depression in extension agents. Journal of Occupational Health Psychology, 5 (1), 56–62. doi:10.1037/1076-8998.5.1.56

Seubert, R. (2012). Treating depressive symptoms more effectively by taking into account overexcitabilities and the third factor. European Psychiatry, 27 (1), 528. doi:10.1016/S0924- 9338(12)74695-3

Sierra, M., Baker, D., Medford, N., & David, A. S. (2005). Unpacking the depersonalization syndrome: An exploratory factor analysis on the Cambridge Depersonalization Scale. Psychological Medicine, 35, 1523–1532. doi:10.1017/S0033291705005235

JOURNAL OF TRAUMA & DISSOCIATION 159

Sierra, M., & Berrios, G. E. (2000). The Cambridge Depersonalization Scale: A new instru- ment for the measurement of depersonalization. Psychiatry Research, 93, 153–164. doi:10.1016/S0165-1781(00)00100-1

Sierra, M., & David, A. S. (2011). Depersonalization: A selective impairment of self-aware- ness. Consciousness and Cognition, 20, 99–108. doi:10.1016/j.concog.2010.10.018

Sierra, M., Senior, C., Phillips, M. L., & David, A. S. (2006). Autonomic response in the perception of disgust and happiness in depersonalization disorder. Psychiatry Research, 145, 225–231. doi:10.1016/j.psychres.2005.05.022

Simeon, D. (2004). Depersonalization disorder: A contemporary overview. Central Nervous System Drugs, 18, 173–179.

Simeon, D., Giesbrecht, T., Knutelska, M., Smith, R. J., & Smith, L. M. (2009). Alexithymia, absorption, and cognitive failures in depersonalization disorder: A comparison to post- traumatic stress disorder and healthy volunteers. Journal of Nervous and Mental Disease, 197 (7), 298–492. doi:10.1097/NMD.obo13e3181aaef6b

Simeon, D., Guralnik, O., Hazlett, E. A., Spiegel-Cohen, J., Hollander, E., & Buchsbaum, H. S. (2000). Feeling unreal: A PET study of depersonalization disorder. American Journal of Psychiatry, 157 (11), 1782–1788. doi:10.1176/appi.ajp.157.11.1782

Simeon, D., Guralnik, O., Knutelska, M., Hollander, E., & Schmeidler, J. (2001). Hypothalamic-pituitary-adrenal axis dysregulation in depersonalization disorder. Neuropsychopharmacology, 25 (5), 793–795. doi:10.1016/S0893-133X(01)00288-3

Simeon, D., Guralnik, O., Knutelska, M., Yehuda, R., & Schmeidler, J. (2003). Basal norepi- nephrine in depersonalization disorder. Psychiatry Research, 121, 93–97. doi:10.1016/ S0165-1781(03)00205-1

Simeon, D., Guralnik, O., Schmeidler, J., Sirof, B., & Knutelska, M. (2001). The role of childhood interpersonal trauma in depersonalization disorder. American Journal of Psychiatry, 158 (7), 1027–1033. doi:10.1176/appi.ajp.158.7.1027

Simeon, D., Knutelska, M., Nelson, D., Guralnik, O., & Schmeidler, J. (2003). Examination of the pathological dissociation taxon in depersonalization disorder. The Journal of Nervous and Mental Disease, 191, 738–744. doi:10.1097/01.nmd.0000095126.21206.3e

Spielberger, C. D. (1983). State-Trait anxiety inventory for adults: Sampler set, manual, test, scoring key. Redwood City, CA: Mind Garden, Inc.

Tieso, C. L. (2007). Overexciatabilities: A new way to think about them. Roeper Review, 29 (4), 232–239. doi:10.1080/02783190709554417

Tschan, R., Wiltnik, J., Adler, J., Beutel, M. E., & Michal, M. (2013). Depersonalization experiences are strongly associated with dizziness and vertigo symptoms leading to increased health care consumption in the German general population. Journal of Nervous and Mental Disease, 201 (7), 629–635. doi:10.1097/NMD.0b013e3182982995

van den Broeck, W., Hofmans, J., Cooremans, S., & Staels, E. (2014). Factorial validity and measurement invariance across intelligence levels and gender of the Overexcitabilities Questionnaire-II (OEQ-II). Psychological Assessment, 26 (1), 55–68. doi:10.1037/a0034475

Van Ijzendoorn, M. H., & Schuengel, C. (1996). The measurement of dissociation in normal and clinical populations: Meta-analytic validation of the Dissociative Experiences Scale (DES-II). Clinical Psychology Review, 16 (5), 365–382. doi:10.1016/0272-7358(96)00006-2

Waller, N., Putnam, F. W., & Carlson, E. B. (1996). Types of dissociation and dissociative types: A taxometric analysis of dissociative experiences. Psychological Methods, 1 (3), 300–321. doi:10.1037/1082-989X.1.3.300

Warne, R. T. (2011). An investigation of measurement invariance across genders on the Overexcitabilities Questionnaire-Two. Journal of Advanced Academics, 22 (4), 578–593. doi:10.1177/1932202X11414821

160 P. THOMSON AND S. V. JAQUE

Wellisch, M., & Brown, J. (2013). Many faces of a gifted personality: Characteristics along a complex gifted spectrum. Talent Development and Excellence, 5(2),43–58.

Wolfradt, U., & Engelmann, S. (2003). Depersonalization, fantasies, and coping behavior in clinical context. Journal of Clinical Psychology, 59, 1117–1124. doi:10.1002/jclp.10204

Wright, M. O., Crawford, E., & Del Castillo, D. (2009). Childhood emotional maltreatment and later psychological distress among college students: The mediating role of maladaptive schemas. Child Abuse and Neglect, 33, 59–68. doi:10.1016/j.chiabu.2008.12.007

JOURNAL OF TRAUMA & DISSOCIATION 161

Copyright of Journal of Trauma & Dissociation is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.