Antipsychotics are medications used primarily to treat the symptoms of psychosis (a severe mental condition in which a patient loses touch with reality). Psychosis is associated with a number of psychiatric disorders, including schizophrenia (a thought disorder that makes it difficult for patients to distinguish between real and unreal experiences) and schizoaffective disorder (a condition in which a person exhibits signs of both schizophrenia and a mood disorder).

Antipsychotics may also be used to treat the psychosis associated with other medical conditions, such as dementia, in some patients. One antipsychotic drug (risperidone) was recently approved by the U.S. Food and Drug Administration to treat irritability in children and adolescents with autism.

Patients with psychoses commonly experience symptoms such as hallucinations (sensory perceptions of phenomena that is not actually present) and delusions (false beliefs held despite evidence to the contrary).

Although antipsychotics do not cure illness, they can often control the disorder by helping to minimize or eliminate symptoms completely.

Antipsychotics affect neurotransmitters (chemical substances released by nerve cells to direct the activity of other cells). They work by blocking blocking certain dopamine (a neurotransmitter essential to thought, motivation, short-term memory and some emotions) receptors. Different dopamine production levels in parts of the brain have been linked to schizophrenia and other thought disorders.

The newer types of antipsychotics (called atypical antipsychotics) function to block certain dopamine and serotonin (a chemical found in the brain, platelets, and digestive tract that acts as a neurotransmitter) receptors.

Most antipsychotics have been shown to be effective in treating symptoms associated with schizophrenia and other types of psychosis. The main difference between the different types of antipsychotics is the potency (the amount prescribed to be effective) and the side effects.

Unlike many prescription medicines which must be taken several times daily, some antipsychotics may be taken orally once a day. Taking antipsychotics at bedtime can help minimize any daytime side effects, such as sedation. Some antipsychotics are available in depot forms that may be injected once or twice a month.

Although many patients are prescribed a single antipsychotic medication, others may be prescribed a combination of antipsychotic drugs.

A common problem among patients taking antipsychotics is non-compliance (not taking the medication as recommended, or not taking it all), which most often causes relapse. When symptoms subside, patients discontinue taking medication believing they no longer need it. Patient education is necessary to inform patients of the long term importance of adhering to medication schedules. Additionally, some patients may require medication monitoring, or even enforced administration of depot forms, to ensure they are taking the antipsychotics as prescribed by their physician.

Depending on the condition being treated, antipsychotic medication may be required for several months or years, or even the patient's entire life.