A number of new antipsychotic drugs (the so-called "atypical antipsychotics") have been introduced since 1990. The first of these, clozapine (Clozaril), has been shown to be more effective than other antipsychotics, although the possibility of severe side effects - in particular, a condition called agranulocytosis (loss of the white blood cells that fight infection) - requires that patients be monitored with blood tests every one or two weeks. Studies show that clozapine works in 30% of patients who have failed all traditional antipsychotic medications. Even newer antipsychotic drugs, such as risperidone (Risperdal), quetiapine (Seroquel), olanzapine (Zyprexa), and Abilify (Aripiprazole) are safer than the older drugs or clozapine, and they also may be better tolerated. They may or may not treat the illness as well as clozapine, however. Several additional antipsychotics are currently under development.
The second atypical antipsychotic, risperidone (Risperdal), appears to have somewhat lower antipsychotic effectiveness, but a greatly improved side-effect profile compared to older medications. Some studies suggest that it also had some antidepressant effects, probably due to its effects on serotonin metabolism. Abilify (Aripiprazole) is even newer and may have other advantages.
Several Advantages
Atypical medications have several advantages over traditional medications: fewer anticholinergic side-effects, less Parkinsonism and dystonia, very low risk of tardive dyskinesia and reversal of many 'negative symptoms' of schizophrenia such as affective blunting, withdrawal, and low motivation. These newer medications all appear to primarily influence dopamine receptors but they also appear to affect serotonin receptors that deal with frontal lobe functions.
Olanzapine (Zyprexa), is described as a safer version of clozapine. It appears to be similar in efficacy and reversal of negative symptoms but free of the risk of agranulocytosis.
Even the older antipsychotic drugs are often very effective in treating certain symptoms of schizophrenia, particularly hallucinations and delusions. Unfortunately, these drugs may not be as helpful with other symptoms, such as reduced motivation and emotional expressiveness. The older antipsychotics (which also went by the name of "neuroleptics"), medicines like haloperidol (Haldol) or chlorpromazine (Thorazine), may even produce side effects that resemble the more difficult to treat symptoms. Often, lowering the dose or switching to a different medicine may reduce these side effects; the newer medicines, including olanzapine (Zyprexa), quetiapine (Seroquel), aripiprazole (Abilify), and risperidone (Risperdal), appear less likely to have this problem. Sometimes when people with schizophrenia become depressed, other symptoms can appear to worsen. The symptoms may improve with the addition of an antidepressant medication.
Clozapine (Clozaril) information
Risperidone (Risperdal) information
Quetiapine (Seroquel) information
Olanzapine (Zyprexa) information
Recent Developments in Atypical Antipsychotic Medications
Clozapine: Efficacy and Safety
Source: Multiple sources, including Schizophrenia National Institute of Mental Health, revised 2006.
