Extrapyramidal syndromes caused by antipsychotics

Extrapyramidal syndromes are significant side effects of antipsychotic therapy due to their severity, frequent occurrence and complications. This paper gives a brief summary of the literature with the emphasis on epidemiology, etiology, diagnosis and differential diagnosis, as well as the treatment of extrapyramidal disorders induced by antipsychotics.

Sustained muscle contractions cause twisting and repetitive movements or abnormal postures. It may appear either as an acute or delayed, i.e. tardive sign. The incidence of dystonia is 2-3% among the patients treated with antipsychotics, and 50% among the ones cured with conventional antipsychotics. AKATHISIA: The main feature of this curious adverse effect is the psychomotor restlessness and the inability to remain motionless. Although akathisia is not very frequent, its incidence and prevalence ranges from 5 to 50% among the treated patients. It is most probably a result of the blockage ofdopaminergic receptors.

The most frequent secondary Parkinsonism is the one caused by drugs. The characteristic parkinsonian signs regress 4 to 16 weeks after the discontinuation of antipsychotic therapy. In the era of atypical antipsychotics this adverse effect appears less frequently.

Involuntary choreatic movements may appear days and months after the introduction of continuous use of antipsychotics. The individual susceptibility may play the major role in the development of this side effect.

Numerous studies have compared conventional and atypical antipsychotics as well as atypical ones with one another in order to decrease the risk of development of extrapyramical side effects as well as to prevent their occurrence and improve their treatment.