Passage: The first-line psychiatric treatment for schizophrenia is antipsychotic medication, which can reduce the positive symptoms of psychosis in about 7 to 14 days. Antipsychotics fail to significantly improve the negative symptoms and cognitive dysfunction. In those on antipsychotics, continued use decreases the risk of relapse. There is little evidence regarding effects from their use beyond two or three years. Use of anti-psychotics can lead to dopamine hypersensitivity increasing the risk of symptoms if antipsychotics are stopped.The choice of which antipsychotic to use is based on benefits, risks, and costs. It is debatable whether, as a class, typical or atypical antipsychotics are better. Amisulpride, olanzapine, risperidone, and clozapine may be more effective but are associated with greater side effects. Typical antipsychotics have equal drop-out and symptom relapse rates to atypicals when used at low to moderate dosages. There is a good response in 40–50%, a partial response in 30–40%, and treatment resistance (failure of symptoms to respond satisfactorily after six weeks to two or three different antipsychotics) in 20% of people. Clozapine is an effective treatment for those who respond poorly to other drugs ("treatment-resistant" or "refractory" schizophrenia), but it has the potentially serious side effect of agranulocytosis (lowered white blood cell count) in less than 4% of people.Most people on antipsychotics have side effects. People on typical antipsychotics tend to have a higher rate of extrapyramidal side effects; some atypicals are associated with considerable weight gain, diabetes and risk of metabolic syndrome. This is most pronounced with olanzapine; risperidone and quetiapine are also associated with weight gain. Risperidone has a similar rate of extrapyramidal symptoms to haloperidol. It remains unclear whether the newer antipsychotics reduce the chances of developing neuroleptic malignant syndrome or tardive dyskinesia, a rare but serious neurological disorder.For people who are unwilling...

Question: How common is Tardive dyskinsia?
rare