Free viewing of sad and happy faces in depression: A potential target for attention bias modification

Background: Identification of reliable targets for therapeutic interventions is essential for developing evidence-based therapies. Attention biases toward negative-valenced information and lack of protective positive bias toward positive-valenced stimuli have been implicated in depression. However, extant research has typically used tasks with narrow stimuli arrays and unknown or poor psychometric properties. Here, we recorded eye-tracking data of depressed and non-depressed participants during a free viewing task to address these limitations.

Methods: Patients with major depressive disorder (MDD; n = 20) and undergraduate students with high (n = 23) and low (n = 20) levels of depression freely viewed 60 different face-based matrices for six seconds each. Each matrix included eight sad and eight happy facial expressions. Gaze patterns on sad and happy areas of interest (AOIs) were explored. Internal consistency for the entire sample and one-week test-retest reliability in the student sub-sample were assessed.

Results: Compared to undergraduates with low levels of depression, patients with MDD and students with high levels of depression dwelled significantly longer on sad faces. Results also showed a significantly longer dwell time on the happy AOI relative to the sad AOI only in the low depression group. The two depressed groups dwelled equally on the two AOIs. The task demonstrated high internal consistency and acceptable one-week test-retest reliability.

Limitations: Only sad and happy facial expressions were used. Relative small sample size.

Conclusion: Relative to non-depressed participants, depressed participants showed prolonged dwelling on sad faces and lack of bias toward happy faces. These biases present viable targets for gaze-contingent attention bias modification therapy.