title: High Incidence and Prevalence of Drug-Related Movement Disorders in Young Patients With Psychotic Disorders.
abstract: BACKGROUND
  Drug-related movement disorders (DRMDs) reduce quality of life and contribute to medication noncompliance of patients with psychotic disorders. Little is known about the epidemiology of DRMDs in relatively young patients a few years after onset of psychosis. This is an important period to study, as the impact of the antipsychotic treatment on the long-term potentiation of the neural pathways associated with psychotic disorders and DRMDs is still minimal. This study investigated the prevalence, incidence, persistence, and clinical correlates of DRMDs in patients during their first years after disease onset.
  
  
  METHODS
  The Genetic Risk and Outcome of Psychosis study is a longitudinal study of 1120 relatively young patients with nonaffective psychosis and a mean age and illness duration of 27 and 4 years, respectively. The following drug-related movement disorders were assessed at baseline and at the 3-year follow-up: parkinsonism, akathisia, tardive dyskinesia, and tardive dystonia. We determined prevalence, incidence, and persistence and investigated clinical correlates at and over the baseline and follow-up assessment.
  
  
  RESULTS
  Patients' mean age and illness duration at baseline were 27.1 and 4.3 years, respectively. In 4 patients, 1 developed a DRMD over the 3-year study period. Prevalence, incidence, and persistence rates were highest for parkinsonism (32%, 21%, and 53%) followed by akathisia (9%, 5%, and 17%) and tardive dyskinesia (4%, 3%, and 20%). Significant associations were found between DRMDs and the patients' age, IQ, and psychopathology.
  
  
  CONCLUSIONS
  The prevalence, persistence, and incidence of DRMDs in this sample were high despite the relatively young age, recent onset of the disorder, and treatment primarily with second-generation antipsychotics. These findings emphasize that screening, diagnosis, and treatment of DRMDs are still important.
authors.affiliation: From the *Innova, GGZ Centraal, Amersfoort; and †Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, the Netherlands.
authors.forename: Thierry Q
authors.initials: TQ
authors.lastname: Mentzel
authors.forename: Ritsaert
authors.initials: R
authors.lastname: Lieverse
authors.forename: Oswald
authors.initials: O
authors.lastname: Bloemen
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Viechtbauer
authors.forename: Peter N
authors.initials: PN
authors.lastname: van Harten
mesh_terms: D000293:Adolescent; D000328:Adult; D017109:Akathisia, Drug-Induced / Q000453:epidemiology / Q000209:etiology*; D001530:Belgium / Q000453:epidemiology; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology*; D004421:Dystonia / Q000139:chemically induced* / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D010302:Parkinson Disease, Secondary / Q000139:chemically induced* / Q000453:epidemiology; D015995:Prevalence; D011618:Psychotic Disorders / Q000188:drug therapy* / Q000453:epidemiology; D000071057:Tardive Dyskinesia / Q000139:chemically induced* / Q000453:epidemiology; D055815:Young Adult