Background: Temporality of the association of low omega-3 polyunsaturated fatty acid (n-3 PUFA) plasma levels with depression remains questionable. To determine the underlying nature of these... Show moreBackground: Temporality of the association of low omega-3 polyunsaturated fatty acid (n-3 PUFA) plasma levels with depression remains questionable. To determine the underlying nature of these associations, this study examined the bidirectional longitudinal associations of n-3 PUFA plasma levels with (presence, onset and course of) depressive disorders and symptoms.Methods: Baseline (n = 2912, 28.6% with current depressive disorder) and 6-year follow-up data (n = 1966, 13.0% with current depressive disorder) of the Netherlands Study of Depression and Anxiety (NESDA) were used. Depression diagnoses and symptoms were based on psychiatric interviews and self-report questionnaires. N-3 PUFA levels (ratio of total fatty acids (mmol%)), were assessed using nuclear magnetic resonance.Results: Using two waves of data, n-3 PUFA levels were lower among depressed persons, as compared to healthy controls (Beta = - 0.047, SE = 0.011, p < .001). Nevertheless, baseline n-3 PUFA levels were not consistently associated with subsequent change in depressive symptoms, onset or remission of depressive disorders over 6 years. Furthermore, the difference in n-3 PUFA levels detected at baseline between depressed and non-depressed participants tended to dissipate over 6 years (depression-by-time estimate: p = .011). Finally, subjects depressed both at baseline and at 6-year follow up had consistently lower n-3 PUFA levels over the entire follow-up as compared to those who had never been depressed. Change in depressive disorders across waves was not consistently accompanied by change in n-3 PUFA levels over time.Limitations: No data on intermediate time points and EPA levels were available.Conclusions: Despite significant cross-sectional associations between n-3 PUFA plasma levels and depressive disorders and severity, this 6-year longitudinal study could not confirm an uni- or bidirectional association over time. The association between depression and n-3 PUFA plasma levels is unlikely to be causal. Show less
This thesis describes a study on neuropsychiatric symptoms in Huntington’s Disease (HD). This cohort study was performed in HD mutation carriers (both pre-motor symptomatic and motor symptomatic),... Show moreThis thesis describes a study on neuropsychiatric symptoms in Huntington’s Disease (HD). This cohort study was performed in HD mutation carriers (both pre-motor symptomatic and motor symptomatic), and a control group of non-carriers that had an a-priori 50% risk for HD. The study started in may 2004 and a second measurement was performed 2 years later. The aim of this study was to study the presence and course of both formal psychiatric disorders and neuropsychiatric symptoms, and to find correlates and predictors associated with the psychiatric phenomena. This cohort study confirms that neuropsychiatric symptoms frequently occur in patients with HD. We expected a diminished insight in patients with a neuropsychiatric symptoms like irritability, but most patients were aware of their irritability. A strong relationship was found between the presence of psychopathology, cognitive functioning and global daily functioning. Irritability may be an early sign of the disease, but only apathy was closely related to the progression of HD indicating a relationship with the progressive neurodegenerative nature of the disease. However, we also found associations with apathy and irritability, and the use of psychotropic medications. Show less
