Critical Review

Schizophrenia

Classes of drugs used to treat schizophrenia

The most significant common medication used in the treatment of schizophrenia is antipsychotic medication. There are two types of drugs that are typical and atypical, both work to reduce the positive or negative effects of schizophrenia. Antipsychotic drugs are used to treat mental, emotional and psychosis conditions. Psychosis refers to the state in which an individual loses touch with reality; the individual starts having hallucinations or delusions.

To alleviate the problem antipsychotic drugs are used to regulate the levels of neurotransmitters in the brain.

Explain their action at the neurotransmitter system.

Schizophrenia is linked to changes in the activities of the neurotransmitter in some specific parts of the brain. Antipsychotic medication affects this neurotransmitter affecting their activity too. The medication acts by interfering with the chemical messengers and controlling or lessening the symptoms of the disorder like mood swings, hallucinations, and delusions. There are mainly two types of antipsychotic drugs that is typical and atypical antipsychotic drugs.

They work by altering dopamine and serotonin receptors. Typical antipsychotics or first generation psychotics were manufactured first in the 1950s. Its function is to block dopamine receptor known as a D2 receptor. Atypical antipsychotics or the second generation antipsychotics were introduced in the 1990s. Just like typical antipsychotic, they block D2 receptors as well as a serotonin receptor known as a 5-HT2A receptor.

Analyze and describe the agonist-antagonist activity of the drugs and the receptor types and subtypes involved in the disorder.

Partial agonists have a lower rate of activity than full agonists at the receptors. This allows them to function as either a functional agonist or functional antagonist depending on the levels of the neurotransmitter (full agonist). If a neurotransmitter is not present partial agonist display a functional antagonist activity. This is as a result of receptor binding reducing any response with the neurotransmitter.

Partial agonist in dopamine D2 receptors is an alternative option when treating schizophrenia. It acts as a functional antagonist mesolimbic dopamine pathway, and the excessive dopamine activity causes positive symptoms. However, reduced dopamine activity in the mesocortical pathway causes cognitive impairment and negative symptoms.

Elaborate on the receptor agonist-antagonist actions of the drugs and describe the most common side effects seen with these drugs.

Inhibition of dopamine function is the most common feature of antipsychotic drugs. D4 receptor activation in moderate levels helps antipsychotic agents protect the brain from negative and cognitive symptoms of schizophrenia. D2 and D3 receptors help improve positive symptoms of schizophrenia but are not successful in countering negative and cognitive symptoms. Some atypical antipsychotics such as clozapine antagonize D2 and D3 receptors and other serotonin receptor subtypes.

Clozapine is the most effective medication against the treatment of schizophrenia. This is because with other treatments they are based on individual’s heterogeneity and how effectively they respond to treatment. This makes it hard to predict how effective a treatment is.

Antipsychotics like all other medications have side effects. By blocking the D2 receptor, the body is affected in the following ways sexual dysfunction, muscle spasms, tremors, and inner restlessness. First generation antipsychotics can affect the menstrual cycle for women and rate of growth of breast tissue for both men and women. Most common effect or significant effect is weight gain and high levels of cholesterol and blood sugar in the body.

One can also get a movement disorder known as tardive dyskinesia that results in uncontrolled muscular, facial and tongue movements and this can be long-term or permanent. Atypical antipsychotics can also bring about lipid disorders and diabetes. These symptoms are associated with olanzapine and clozapine.

Evaluate the risk-benefits of drug use for this disorder.

Patients benefit from antipsychotic drug treatment in a long-term goal to prevent a relapse. Through neuroimaging, it suggests that if a patient seeks treatment early enough, they stand to benefit a lot more from the treatment and get over the disorder and be able to go back to the normal life they were living.

Delaying or withholding treatment reduces the long-term benefits of the treatment. From the current research, the therapeutic benefits outweigh the risks, and there has been no evidence to suggest that this type of treatment increases the chances of relapse in patients. Some patients who

have undergone the process have recovered from their psychotic periods although there is no bio maker to determine what number or percentage.

Lastly, it is detrimental to withhold treatment especially for a schizophrenia patient and should go through with treatment as it could help improve the already worse condition.

References

Howes, O. D., & Murray, R. M. (2014). Schizophrenia: an integrated socio-developmental-cognitive model. The Lancet, 383(9929), 1677-1687.

Kapur, S., Zipursky, R., Jones, C., Remington, G., & Houle, S. (2000). The relationship between dopamine D2 occupancy, clinical response, and side effects: a double-blind PET study of first-episode schizophrenia. American Journal of Psychiatry, 157(4), 514-520.