Prevalence of neuroleptic-induced movement disorders: an 8-year follow-up study in chronic schizophrenia inpatients.

Background: Atypical antipsychotic drug use by schizophrenia patients in Estonia increased from 32% in 2004 to 61% in 2009.

Aims: To assess the prevalence of neuroleptic-induced movement disorders in the Estonian institutionalized population of schizophrenia patients twice over a period of eight years, before and after introduction of atypical antipsychotic drugs using DSM-IV criteria.

Methods: DSM-IV criteria and specific rating scales were used to evaluate the prevalence of neuroleptic-induced movement disorders among 72 patients who participated in the study in 2009 compared to 99 patients who participated in 2001.

Results: Despite increased use of atypical antipsychotics in the study population (up to 30% from 20%), the proportion of movement disorder-free population remained the same over 8 years - 38.9% in 2001 versus 38.4% in 2009. There were significant intra-individual fluctuations. Use of a typical antipsychotic resulted in an almost seven times higher risk of tardive dyskinesia after 8 years. Doses of antipsychotic drugs had no effect on the severity of neuroleptic-induced movement disorders.

Conclusions: Unfortunately, in 18% of patients the switch of medication from typical to atypical did not change the overall prevalence of neuroleptic-induced movement disorders in the group. The long-term benefit of atypical antipsychotics requires further research in patients who are treated with antipsychotics for years.