Psychotropic Drugs
Psychotropic Drugs
EFFICACIOUS USE OF PSYCHOTROPIC DRUGS
Psychotropic drugs are substances prescribed to affect one’s behavior, emotions, or cognition. They can be categorized into the following drug classes: antipsychotics, antidepressants, anxiolytics, mood stabilizers, and stimulants. Psychotropic drugs are routinely used to treat various mental disorders, and their efficacy is determined by how well the drug decreases the presenting symptoms of a disorder, as well as the presence or absence of side effects.
PSYCHOTROPIC DRUG CLASSES
Antipsychotics are prescribed primarily to manage the symptoms associated with schizophrenia, autism, and other developmental disabilities. On occasion, they are used in combination with other drugs to treat depression and bipolar disorder. There are two classes of antipsychotic drugs: typical and atypical. The difference between these two groups lies in their mechanism of action. Typical antipsychotics are highly selective for dopamine receptors, specifically D2 receptors. Unfortunately, because of this selectivity, movement disorders (e.g., tardive dyskinesia) are a side effect of the typical antipsychotics. Given this undesirable side effect, atypical antipsychotics were developed. They differ from the typical antipsychotics in that they have a lower affinity for D2 receptors, and affect other neurotransmitter systems such as serotonin. Atypical antipsychotics have significantly fewer motor side effects; however, weight gain is an issue.
Antidepressants are used in the treatment of depression, post-traumatic stress disorder, anxiety, and obsessive compulsive disorder. There are three major classes of anti-depressants prescribed: monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), and selective serotonin reuptake inhibitors (SSRIs). The best known of these is the SSRI. SSRIs exert their effect by blocking the reuptake of serotonin from the synapse into the presynaptic neuron, thus increasing its availability postsynaptically. Physiological side effects associated with SSRIs are usually minimal and transient, with the exception of sexual dysfunction. Increases in suicide ideation in adolescents treated with SSRIs have been reported, and thus SSRIs are not generally recommended for use with this population. Despite their popularity, SSRIs have not been found to be any more effective at treating depression than any other antidepressant.
Anxiolytics are prescribed to treat anxiety and sleep disorders. There are two classes of anxiolytics, benzodiazepines and non-benzodiazepines. Benzodiazepines exert their effects by increasing the efficiency of gammaaminobutyric acid (GABA), an inhibiting neurotransmitter. These drugs are fast-acting, and side effects include the potential for physiological addiction. Non-benzodiazepines include buspirone, which exerts its effect via activity at serotonin receptors. The potential for abuse with non-benzodiazepines is less than with benzodiazepines, but they also appear to be less effective at treating anxiety disorders than benzodiazepines.
Although lithium is the only drug used specifically for the treatment of bipolar disorder, anticonvulsants such as lamotrigine also have been demonstrated to have mood-stabilizing properties. At the present time, the neuropharmacology of these drugs in the treatment of mood disorders is not understood, and both lithium and certain anticonvulsants require routine blood monitoring to guard against toxicity.
Finally, stimulants are prescribed to treat attention disorders such as attention deficit/hyperactivity disorder (ADHD). These drugs operate by increasing the availability of dopamine, epinephrine, norepinephrine, and/or serotonin. Side effects associated with stimulants are decreased appetite and difficulty sleeping.
EFFICACIOUS USE OF PSYCHOTROPIC DRUGS
Prior to the advent of psychotropic drugs in the late 1940s, treatment of psychiatric disorders included admittance to asylums, physical restraints, and psychoanalysis. Consistent and effective results of treatment were often elusive. Advances in technology and the convergence between the fields of psychiatry, neurology, genetics, and neuroscience have made it possible to evaluate the therapeutic effects of psychotropic drug use, and to make predictions about who will respond well to their use. The application of neuroimaging techniques such as functional magnetic resonance imaging (fMRI) to drug evaluation allows assessment of changes in cerebral blood flow, volume, and oxygenation as a function of psychotropic drug use that may provide an indication of the efficaciousness of psychotropic treatment in disorders such as schizophrenia and depression (Tracey and Wise 2001). Psychopharmacogenomics is another approach that attempts to predict efficacious drug treatment (Malhotra, Murphy and Kennedy 2004). The goal is to identify polymorphisms or mutations of genes involved in receptor function, pharmacokinetics, and pharmacodynamics, to determine who is at an increased risk for experiencing side effects of psychotropic drugs. With each of these technological advances, the aim is to improve prescribing practices and provide individualized, effective treatment while ensuring quality of life.
SEE ALSO Adolescent Psychology; Cognition; Emotion; Genomics; Mental Health; Mental Illness; Neuroscience; Psychoanalytic Theory; Psychology; Psychoneuroendocrinology; Psychoneuroimmunology; Psychotherapy; Suicide
BIBLIOGRAPHY
Malhotra, Anil K., Greer M. Murphy, and James L. Kennedy. 2004. Pharmacogenetics of Psychotropic Drug Response. American Journal of Psychiatry 161 (5): 780–796.
Stahl, Stephen M. 2000. Essential Psychopharmacology: Neuroscientific Basis and Practical Applications. 2nd ed. Cambridge, U.K.: Cambridge University Press.
Tracey, Irene, and Richard G. Wise. 2001. Pharmacological fMRI: A New Tool for Drug Development in Humans. Journal of Pharmacy Practice 14 (5): 368–375.
Maria G. Valdovinos