The mainstay treatment for schizophrenia is antipsychotic drugs, medications that work to alter brain chemistry in a particular way. Older antipsychotic drugs, including Thorazine, Haldol, and Prolixin, worked well for "positive" symptoms but less well for "negative" symptoms. They were also fraught with side effects including persistent muscle spasms, tremors, and muscle rigidity.
In a newer class of drugs known as "atypical antipsychotics" was developed in the 1990s. The first, Clozaril, remains extremely effective even in those patients who do not respond to other medications. However, it can also cause a problem known as "agranulocytosis," a serious loss of white blood cells, requiring weekly or biweekly blood tests.
Drugs developed after Clozaril include Abilify, Fanapt, Geodon, Invega, Latuda, Risperdal, Saphris, Seroquel, and Zyprexa. Some of these drugs can cause weight gain and may increase the risk of diabetes or high blood lipids (for example, cholesterol).
Generally speaking, many patients respond to antipsychotic drugs quickly, with hallucinations improving within days to weeks and delusions often improved within several weeks (particularly if they are not longstanding). For some patients, symptoms substantially improve after a few weeks of treatment, while for others, positive and negative symptoms may persist despite appropriate medications.