Screening for cognitive dysfunction in unipolar depression: Validation and evaluation of objective and subjective tools

•The SCIP-D is valid to screen for objective cognitive dysfunction in depression.•The COBRA is valid to screen for subjective cognitive difficulties in depression.•A combined SCIP-D-COBRA measure is optimal to screen for cognitive impairment.•The three SCIP-D forms are equivalent and may be used for monitoring cognition.•Subjective cognitive difficulties correlate with socio-occupational impairment.

BackgroundPersistent cognitive dysfunction in unipolar depression (UD) contributes to socio-occupational impairment, but there are no feasible methods to screen for and monitor cognitive dysfunction in this patient group. The present study investigated the validity of two new instruments to screen for cognitive dysfunction in UD, and their associations with socio-occupational capacity.MethodParticipants (n=53) with UD in partial or full remission and healthy control persons (n=103) were assessed with two new screening instruments, the Danish translations of the Screen for Cognitive Impairment in Psychiatry (SCIP-D) and Cognitive Complaints in Bipolar Disorder Rating Assessment (COBRA) and with established neuropsychological and self-assessment measures. Depression symptoms and socio-occupational function were rated with the Hamilton Depression Rating Scale and Functional Assessment Short Test respectively.ResultsThe SCIP-D and COBRA were valid for detection of objective and subjective cognitive impairment, respectively. The three parallel SCIP-D forms were equivalent. A combined SCIP-D-COBRA measure showed high sensitivity and good specificity for objective cognitive impairment (91% and 70%, respectively). There was no correlation between subjective and objective measures of cognition. Subjective cognitive difficulties correlated more with socio-occupational impairment (r=0.7, p<0.01) than did objective cognitive difficulties, for which there was a weak correlation with the executive skills domain only (r =−0.3, p=0.05).LimitationsA modest sample size.ConclusionsThe SCIP-D and COBRA are valid measures of objective and subjective cognitive impairment, respectively, and should ideally be implemented together in the screening for cognitive dysfunction in UD.