Cognitive assessment of depression: a new test for mood disorders

Object: Current methods of assessment of major depression are biased by consistent discordancies between self- andobserver-ratings of depression. Cognitive distortions are a regular core symptom of major depression, and are associated withthe development of hopelessness and suicidality.Method: Based on previous studies showing that patients who were diagnosed with major depressive disorders deniedpositive statements and endorsed more negative statements about themselves than normal subjects, we developed a computer-ized test with two tasks: a self-description task during which subjects were asked to self-attribute or refuse positive and negativeadjectives, and a recognition memory task during which subjects were asked to recognize the same adjectives randomly mixedwith semantically similar others. We tested 294 normal subjects and 247 patients affected by a major depressive episode.Results: In normal subjects frequencies and latencies of both self-attribution and recognition of positive stimuli wereenhanced in respect to negative stimuli, while in depressed patients negative self-scheme elements predominated in self-description, and information processing was slower for positive and negative elements. Single output measures were com-bined in a single score (named depressive differential) based on canonical coefficients derived from discriminant functionanalysis, which could correctly classify 92% of patients and 98% of controls. ROC analysis of depressive differential scoresshowed AUC=0.987, and two-graphs ROC analysis estimated sensitivity and specificity at 0.955 for the optimal cutoff value.Internal and external validity testing showed high correlations both with commonly used psychiatric rating scales and withinstruments specifically developed to assess depressive cognitive style. Test-retest reliability was high.Conclusions: Further studies will define the diagnostic power in respect to depressive syndromes pertaining to diagnosesother than mood disorders, and will precise if, and when, the observed distortions normalize during antidepressant treatment