Physiological responses to medication Differences in drug metabolism Drug metabolism is controlled by a number of specific enzymes, and the action of these enzymes varies among individuals. For example, most individuals show normal activity of the IID6
isoenzyme that is responsible for the metabolism of many
tricyclic antidepressant medications and most antipsychotic drugs. However, studies have found that one-third of Asian Americans and African Americans have a genetic alteration that decreases the metabolic rate of the IID6 isoenzyme, leading to a greater risk of side effects and toxicity. The
CYP2D6 enzyme, important for the way in which the liver clears many drugs from the body, varies greatly between individuals in ways that can be ethnically specific.
Cultural influences on psychiatric healthcare In addition to biology and environment,
culturally determined attitudes toward illness and its treatment may affect how an individual responds to psychiatric medication. Some cultures see suffering and illness as unavoidable and not amenable to medication, while others treat symptoms with
polypharmacy, mixing medications with herbal drugs. Cultural attitudes can also have an effect on adherence to medication regimes and influence the
placebo effect.
Diagnosis of psychological conditions The way an individual expresses and reacts to the symptoms of psychiatric illness, and the cultural expectations of the physician, may affect the diagnosis a patient receives. For example,
bipolar disorder often is misdiagnosed as schizophrenia in people of color. ==Concerns in research and practice methodologies==