Neurocognitive function following remission in major depressive disorder: potential objective marker of response?

Objective: Neurocognitive deficits have been widely reported in patients with mood disorders. However, relatively little is known of the short-term trajectory of neurocognitive improvement once treatment has been initiated.Method: A neurocognitive test battery was administered to unipolar depressed (major depressive disorder, MDD) patients (aged 18-65 years) who had been medication-free for at least 6 weeks, and to healthy controls. Patients were then treated according to clinical need, predominantly with standard pharmacotherapy, and all participants were followed up within 6 months.Results: Of the 25 MDD patients who returned at follow up, 11 were defined as remitted and 14 as not remitted. Significantly less baseline psychomotor dysfunction was observed in patients who remitted compared to those who did not (effect size, d = 0.78, 95% confidence interval (Cl) =0.07-1.44). Analysis of the change scores between assessments revealed a significantly greater improvement in verbal memory in patients who remitted compared to those who did not (d =0.73, 95%CI = 0.03-1.39).Conclusions: This preliminary report suggests that there may be distinct temporal trajectories of neurocognitive improvement following remission in MDD. Aspects of neurocognitive functioning should be examined further as a means of providing a useful objective marker of treatment response.