Recognition memory for neutral faces in depression

Aims: To determine whether major depressive disorder (MDD) gives rise to deficient recognition of neutral faces.

Methods: 18 patients with MDD, according to DSM IV criteria, and 24 healthy volunteers were recruited. Patients were in remission during the study. Participants were required to discriminate 50 target faces (black and white photographs of male faces with neutral expressions), exposed for 3000 ms during a study phase, from 50 novel distracter faces introduced during the test phase. For all positive identifications (target hits as well as distracter false alarms) made during the test phase, participants indicated whether these were based on recollection of the face having been presented earlier, or limited to feelings of knowing/familiarity occurring in the absence of recollection.

Results: The results were analysed in terms of overall recognition of faces using the signal detection measure d prime (d'), recollection rates (hit rate minus false alarm rate) and familiarity (d'). The MDD group was significantly impaired on measures of facial recognition memory (F = 15.05, p<0.001) and familiarity driven recognition decisions (F = 14.66, p<0.001). Recollection rates also approached significance (F = 3.93, p = 0.054).

Conclusions: These findings suggest that MDD is not limited to only deficits in recognition of facial emotion cues, but also extends to recognition memory for neutral faces. Furthermore, this memory impairment is most evident in the processes which subserve feelings of familiarity. An abnormality in the subjective experience of familiarity may have clinical implications for patients’ reports of derealisation and depersonalisation. These findings also suggest that patients with MDD have impairments in familiarity driven recognition even when apparently recovered from an episode of illness.