title: The validity of the Beck Depression Inventory as a screening and diagnostic instrument for depression in patients with Parkinson's disease.
abstract: OBJECTIVE
  To evaluate the validity of the Beck Depression Inventory (BDI) as a screening and diagnostic scale for depression in Parkinson's disease (PD).
  
  
  METHODS
  Fifty-three nondemented patients with PD were diagnosed according to a standardized protocol consisting of the depression module of the Structured Clinical Interview for DSM axis I disorders (SCID) and the BDI. A "receiver operating characteristics" (ROC) curve was obtained and the sensitivity, specificity, positive and negative predictive values (PPV and NPV, respectively) were calculated for different cut-off points of the BDI.
  
  
  RESULTS
  Maximum discrimination was obtained with a cut-off score of 13/14. High sensitivity and NPV were obtained with cut-off scores of 8/9 or lower; a high specificity and PPV were obtained with cut-off scores of 16/17 or higher. The area under the ROC curve was 85.67%.
  
  
  CONCLUSIONS
  A single cut-off score on the BDI to distinguish nondepressed from depressed patients with PD is not feasible. If one accepts the low specificity, then the BDI can be used as a valid screening instrument for depression in PD with a cut-off of 8/9. With a cut-off score of 16/17, it can be used as a diagnostic scale, at the cost of a low sensitivity. The use of diagnostic criteria for depression remains necessary.
authors: Department of Psychiatry, Maastricht University Hospital, The Netherlands.
authors: A F
authors: AF
authors: Leentjens
authors: F R
authors: FR
authors: Verhey
authors: G J
authors: GJ
authors: Luijckx
authors: J
authors: J
authors: Troost
mesh_terms: D000368:Aged; D003863:Depression / Q000175:diagnosis* / Q000209:etiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000523:psychology*; D011237:Predictive Value of Tests; D011569:Psychiatric Status Rating Scales / Q000592:standards*; D011594:Psychometrics; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity