Longitudinal associations between melancholic depression and executive function in adult patients with major...

Major depressive disorder (MDD) is often associated with deficits in executive function, but the long-term cognitive impact of specific depressive subtypes, in particular melancholic depression (MelD), is underexplored. This is the first prospective study aimed at exploring longitudinal associations between MelD and executive function in adult patients with MDD. This is a secondary analysis using data from a larger project with assessments at baseline, 6 and 12 months. MelD was identified using an algorithm derived from a subset of eight items from the Inventory of Depressive Symptomatology-Self Rated, which provides a standardized framework for the identification of this specific depressive subtype. Executive function was assessed using the Cambridge Neuropsychological Test Automated Battery. Longitudinal associations between MelD and executive function, including a global domain, four subdomains (working memory, planning, response inhibition and decision-making), and eight individual variables used to calculate the composite scores of the five (sub)domains, were analyzed using linear mixed-effects models adjusted for demographic and clinical variables and psychomotor speed. One hundred and five patients (20.95 % MelD) were analyzed at baseline, 73 (17.81 % MelD) at 6 months, and 61 (19.67 % MelD) at 12 months. MelD, older age and female sex were significantly associated with worse performance in the global executive function domain, in the working memory subdomain, and in four individual variables within the working memory, planning and decision-making subdomains, independent of other demographic and clinical variables and psychomotor speed. The findings highlight MelD as a distinct risk factor for worse long-term executive function in adult patients with MDD.