Spontaneous and drug-induced movement disorders in schizophrenia.
The extrapyramidal side-effects (EPS) of conventional neuroleptics are widely recognized. However, a substantial number of drug-naïve patients exhibit movement disorders which could be mistaken for EPS if drug therapy were started without a careful baseline assessment. Patients' experience of EPS during their first exposure to antipsychotic medication can have lasting effects on their attitudes to medication and compliance. Unmedicated, approximately 60% of patients will relapse in the first year after resolution of an acute psychotic episode, whereas prophylactic medication can reduce the relapse rate to less than 20%. The conventional neuroleptics produce antipsychotic effects at doses which differ little from those that induce EPS, and although anticholinergic medication helps to reduce the severity of EPS, it also causes side-effects, e.g. constipation, blurred vision, retention of urine, dry mouth and disturbances of sexual function. More importantly, anticholinergic drugs may worsen the psychosis and impair memory. Low or intermittent dose strategies with conventional neuroleptics may give patients relief from EPS, but they increase the relapse risk, and may also increase the risk of tardive dyskinesia. The serotonin-dopamine antagonist (SDA) antipsychotics, such as risperidone, produce both significant antipsychotic effects at doses which are lower than those that cause EPS, and also a lower level of EPS compared with conventional drugs. Clinical trials have shown that risperidone is effective in first-episode schizophrenia. In these trials the same doses were used as in chronic patients. However, clinical experience in Canada since the drug became generally available in 1993 suggests that first-episode patients require lower doses of risperidone than chronically ill patients who have had several acute psychotic episodes. More than 3 years of use has made it clear that risperidone should be seriously considered in first-episode patients, as it offers an opportunity to treat psychosis with minimal EPS. This in turn should lead to better compliance and a lower long-term relapse rate.
Kopala
L C
LC
Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.
D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D018680:Cholinergic Antagonists / Q000009:adverse effects / Q000627:therapeutic use; D002908:Chronic Disease; D004305:Dose-Response Relationship, Drug; D004409:Dyskinesia, Drug-Induced / Q000175:diagnosis* / Q000188:drug therapy; D006801:Humans; D009460:Neurologic Examination / Q000187:drug effects; D011788:Quality of Life; D012008:Recurrence; D012307:Risk Factors; D018967:Risperidone / Q000009:adverse effects / Q000627:therapeutic use; D012559:Schizophrenia / Q000175:diagnosis / Q000188:drug therapy*
D014150:Antipsychotic Agents; D018680:Cholinergic Antagonists; D018967:Risperidone