Medications to Treat Schizophrenia

The following drugs are used to treat schizophrenia:

Antipsychotic medications are the main drugs used to treat schizophrenia. Their introduction in the 1950s marked a breakthrough in the treatment of psychosis, the results of which were apparent in the reduction of hospitalized patients. It is estimated that 300,000,000 people worldwide have been treated with them—more than the current population of the United States.

Antipsychotics reduce delusions and hallucinations, and improve overall function. Generally, they are divided into two subgroups, traditional and atypical, which are used according to a person's response to treatment and tolerance of side effects.

Traditional antipsychotics include chlorpromazine (Thorazine), haloperidol (Haldol), fluphenazine (Permitil, Prolixin), and perphenazine (Trilafon). These drugs primarily block the effects of the dopamine 2 (D2) receptor, which are thought to be hyperactive in the brains of people with schizophrenia. This is supported by the fact that dopamine suppression seems to improve schizophrenic symptoms. Excessive numbers of dopamine receptors have been found in the brains of some people with untreated schizophrenia.

Dopamine is a neurotransmitter important to the combined function of the limbic system and frontal regions of the brain. Among other functions, it assists in motor behavior, pleasure, and thought and memory processes.

Thorazine is considered a low-potency drug. It frequently causes the following side effects associated with suppression of the neurotransmitter acetylcholine:

  • Constipation
  • Dizziness
  • Dry mouth
  • Sedation
  • Urinary retention

Acetylcholine is important in the brain in counterbalancing dopamine levels. Neuromuscular and neurological side effects are less common with low-potency antipsychotics, but may occur in some people. These include the following:

  • Acute dystonia (brief involuntary muscle spasm and twisting)
  • Akathisia (severe restlessness that leads to agitation and anxiety)
  • Mask-like expression
  • Pseudo-Parkinson's disease (muscle tremor)
  • Shuffling, unstable gait

Haldol and Prolixin are high-potency drugs used in treating schizophrenia. High-potency drugs are more likely than low-potency drugs to cause neuromuscular side effects. Their other versions, Haldol Deconoate and Prolixin Deconoate, are long-acting injectable drugs (LAIs) used to ensure dosage compliance in people who may not consistently take oral medication. They are given as a deep intramuscular injection—Haldol Deconoat once a month and Prolixin Deconoate every two weeks.

In October 2015, the FDA approved aripiprazole lauroxil (Aristada) extended release injection to treat schizophrenia in adults. This medication is injected by a health care provider every 4 to 6 weeks. The most common side effect is akathisia.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 Jan 2001

Last Modified: 09 Oct 2015