Schizophrenia Medication Side Effects & Limitations

In addition to other general side effects, there are limitations to all antipsychotic medications. For example, while they are useful in reducing the positive symptoms of schizophrenia, like delusions, hallucinations, and disorganized speech, they are typically not as effective in controlling negative symptoms, like lack of emotion and loss of will.

Generally, people who take traditional anitpsychotics always feel like they are on medication. They can seem confused or lost, which can adversely affect their judgment and physical performance. For these reasons, they frequently do not take their medication, so compliance is a concern.

Tardive dyskinesia (TD) is an involuntary movement disorder that causes slow, nonrhythmic muscle movements, intense aching, and painful spasms. It may appear late in the treatment of schizophrenia as a result of long-term use of antipsychotic medication, and can affect specific muscles or general muscle groups, from the tongue to the muscles of the arms and legs. Every year, another 4 percent of people taking traditional antipsychotic drugs develop TD. There is no known effective treatment for TD, and it may be irreversible.

Perhaps as many as 30 percent of people are not affected by traditional antipsychotics and may find benefit from treatment with atypical antipsychotics.

Atypical antipsychotics, like clozapine (Clozaril), are the most recent class of drugs used in schizophrenia treatment. Clozapine's method of action only slightly affects the D2 receptor. It primarily blocks other dopamine receptors and other neurotransmitters, like norepinephrine, histamine, and, especially, serotonin. Atypical antipsychotics have helped more than 50 percent of people who could not improve with traditional antipsychotics.

There are two main advantages to clozapine. First, it significantly improves negative symptoms as well as positive symptoms; traditional anitpsychotics typically only control positive symptoms. Secondly, it is not associated with TD, probably because TD results when the D2 receptor is affected. For these reasons, clozapine is the benchmark for schizophrenia treatment.

In addition to the side effects common with traditional anitpsychotics, like sedation, dry mouth, and dizziness, clozapine is associated with agranulocytosis, an acute disease characterized by significant loss of white blood cells. It may be especially common in the first two years of treatment and slightly more than 1 percent of people treated with clozapine develop it every year. Therefore, weekly or biweekly blood-level checks are necessary during treatment with clozapine to ensure proper white blood cell levels. This makes it an unpopular drug among patients.

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

Published: 31 Jan 2001

Last Modified: 02 Oct 2015