title: Development and evaluation of the Parkinson Psychosis Questionnaire A screening-instrument for the early diagnosis of drug-induced psychosis in Parkinson's disease.
abstract: OBJECTIVE
  Drug-induced psychosis is a frequent side-effect in the treatment of advanced Parkinson's disease (PD). We sought to develop and evaluate a brief instrument for early recognition of drug-induced psychosis in PD.
  
  
  METHODS
  We developed the "Parkinson Psychosis Questionnaire" (PPQ), which consists of screening questions for typical early signs and psychotic symptoms in PD and which quantifies the frequency and severity of four clinical categories-sleep disturbances, hallucinations/illusions, delusions and orientation. We performed an internal validation of the PPQ in 50 unselected patients with parkinsonism. The Brief Psychiatric Rating Scale (BPRS) and the "Structurized Clinical Interview" (SCID) for DSM IV were applied to the same patients as external references.
  
  
  RESULTS
  Of 50 subjects, 49 suffered from idiopathic PD and one from probable MSA-P. Hoehn and Yahr stages in "on" ranged from 1.5 to 4. Sensitivity of the PPQ test for drug-induced psychosis according to SCID was 100 % (95 % CI: 73.5%, 100%); while specificity was 92.1 % (95% CI: 78.6%, 98.3 %). The PPQ severity score was highly correlated with BPRS. We derived a linear prediction formula, which transformed PPQ into BPRS scores.
  
  
  CONCLUSIONS
  The PPQ appears to be a suitable, and easily administered instrument for early diagnosis of drug induced psychosis in routine PD care. Whether the PPQ could also be a valuable tool for monitoring follow-up studies and therapeutic intervention trials remains to be tested.
authors.affiliation: Dept. of Neurology, Philipps-University Marburg, Rudolf-Bultmann-Strasse 8, 35039 Marburg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Brandstaedter
authors.forename: S
authors.initials: S
authors.lastname: Spieker
authors.forename: G
authors.initials: G
authors.lastname: Ulm
authors.forename: U
authors.initials: U
authors.lastname: Siebert
authors.forename: T E
authors.initials: TE
authors.lastname: Eichhorn
authors.forename: J C
authors.initials: JC
authors.lastname: Krieg
authors.forename: W H
authors.initials: WH
authors.lastname: Oertel
authors.forename: K
authors.initials: K
authors.lastname: Eggert
mesh_terms: D000978:Antiparkinson Agents / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D020734:Parkinsonian Disorders / Q000188:drug therapy*; D011605:Psychoses, Substance-Induced / Q000175:diagnosis*; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires
chemical_list: D000978:Antiparkinson Agents