What About Side Effects?
Antipsychotic drugs, like virtually all medications, have unwanted effects along with their beneficial effects. During early treatment, patients may be troubled by side effects such as drowsiness, restlessness, muscle spasms, tremor, dry mouth, or blurring of vision. Most of these can be corrected by lowering the dosage or controlled by other medications. Different patients have different treatment responses and side effects to various antipsychotic drugs. A patient may do better with one drug than another.
The long-term side effects of antipsychotic drugs may pose a considerably more serious problem. Tardive dyskinesia (TD), as mentioned, is a disorder characterized by involuntary movements most often affecting the mouth, lips, and tongue, and sometimes the trunk or other parts of the body such as arms and legs. It occurs in about 15% to 20% of patients who have been receiving the older, "typical" antipsychotic drugs for many years. But TD can also develop in patients who have been treated with these drugs for shorter periods of time. In most cases, the symptoms of TD are mild and the patient may be unaware of the movements.
Antipsychotic medications developed in recent years all appear to have a much lower risk of producing TD than their older counterparts, traditional antipsychotics. The risk is not zero, however, and they can produce side effects of their own such as weight gain. In addition, if given at too high of a dose, the newer medications may lead to problems such as social withdrawal and symptoms resembling Parkinson's disease, a disorder that affects movement. Nevertheless, the newer antipsychotics are a significant advance in treatment, and their optimal use in people with schizophrenia is a subject of much current research.
National Institutes of Mental Health