Roxanne Schaakxs

THE COURSE OF MAJOR DEPRESSIVE DISORDER ACROSS THE LIFE SPAN ABSTRACT Background → We examined whether older age significantly determined a poorer trajectory of the two-year naturalistic course of MDD, and established which prognostic clinical, social, and health factors explained this potential poorer course. Age-related course differences may affect optimization of MDD treatment. Methods → Baseline and two-year follow-up data were used from two cohorts: the Netherlands Study of Depression and Anxiety (NESDA) and the Netherlands Study of Depression in Older Persons (NESDO). 1,042 persons (66.2% female) between 18-88 years with a current MDD diagnosis at baseline were included. Associations were assessed between continuous age per 10 years and four MDD course indicators: having a depression diagnosis after two years, having a chronic symptom course, time to remission and depression severity change. Examined prognostic indicators, possibly contributing to age differences, were clinical (e.g. co-morbid anxiety), social (loneliness, social support), and health (BMI, pain, chronic diseases) factors. Outcomes → Older age was significantly associated with a worse two-year MDD course for all four indicators (depressive disorder: OR=1.08;95%CI=1.00-1.17; chronic course: OR=1.23;95%CI=1.12-1.36, time to remission: HR=0.91;95%CI=0.86-0.96; depression severity change: B=1.06,p<.001). The course of MDD worsened linearly with age. These findings only reduced slightly, and remained mostly significant, when adjusting for prognostic clinical, social and health factors. Interpretation → Older age was found to be an independent risk factor for a worse MDD course, which could not be explained by a range of well-established risk factors for MDD. Further investigation of potential other underlying mechanisms is desired to prevent negative consequences of a long-term MDD burden in older persons. Funding → Netherlands Organisation for Health Research and Development (Zon-Mw), Fonds NutsOhra; Stichting tot Steun VCVGZ, NARSAD The Brain and Behaviour Research Fund, European Union Seventh Framework Programme (FP7/2007-2013). 65