Effect of antidepressive therapy on retinal contrast processing in depressive disorder

Background Recently, we reported a reduced retinal contrast gain in unmedicated and medicated patients with major depression. Aims To analyse whether the contrast gain normalises after successful antidepressive therapy by recording the pattern electroretinogram (PERG) in healthy controls and patients with depression before and after antidepressive therapy. Method Fourteen patients diagnosed with major depression were repeatedly scanned and the results compared with that from 40 matched controls. Results The retinal contrast gain was lower at baseline in patients with depression, was normalised with remission and correlated with the severity of depression. Patients who did not achieve remission retained significantly lower contrast gain at follow-up. Conclusions The study provides evidence for a state-dependent modulation of retinal contrast gain in patients with major depression. Reduced contrast gain normalised after therapy. A PERG-based contrast gain could serve as a state marker of depression.