People with depression may be less likely to misclassify ambiguous facial expressions as happy, according to preliminary results from a facial expression recognition study published in the Journal of Affective Disorders.

To further test the theory that people with depression interpret self-referential social information negatively, investigators conducted a prospective cohort study of individuals who presented with depressive symptoms at participating general surgery clinics in the United Kingdom. Enrolled patients attended 4 study visits, each 2 weeks apart, either at home or at their primary care clinic. Depressive symptoms were assessed at each visit per the Patient Health Questionnaire (PHQ-9). Participants performed a computerized facial expression recognition task at the first 3 study visits. During the task, participants were presented with a facial stimulus and then asked to select the perceived emotion from a multiple-choice list. Each emotion was presented in 15 intensities, beginning with an ambiguous facial expression and intensifying to clearer expressions over subsequent trials. An “unbiased hit rate” was calculated for happy and sad facial expressions only, although 6 total emotions were represented across the computerized task. The unbiased hit rate captured patient ability to correctly identify an emotion while adjusting for any tendency to select that emotion when it was not present.

A total of 509 patients were recruited for the original sample, among whom 505 completed the first facial recognition task. At baseline, 45% of patients met diagnostic criteria for depression, and the mean PHQ-9 score in the total sample was 10.38 (standard deviation, 6.62). Overall, participants were more likely to correctly identify happy facial expressions compared with sad facial expressions (P