Trajectories of generalized anxiety disorder, major depression and change in quality of life in adults aged 50 + : findings from a longitudinal analysis using representative, population-based data from Ireland.

PURPOSE: To investigate the longitudinal association between trajectories (incidence, remission) of generalized anxiety disorder (GAD), major depression (MD) and change in quality of life (QoL) in adults aged 50 + , and to assess the symmetry in these relationships using observational study data.
METHODS: Data were derived from two waves of The Irish Longitudinal Study on Aging (2014-2015, wave 3: n = 6400; 2016, wave 4: n = 5715), a nationally representative cohort of community-dwelling adults aged 50 +. GAD and MD were assessed by means of the short form of the Composite International Diagnostic Interview. QoL outcomes were assessed using the Control, Autonomy, Self-realization, and Pleasure scale (CASP-12 with two domains control/autonomy and self-realization/pleasure). Covariate-adjusted, asymmetric fixed effects panel regressions and post-estimation Wald tests were used for statistical analysis.
RESULTS: Regarding incident disorders, only incident MD was significantly associated with a reduction in QoL over time (control/autonomy domain: b = - 0.74, SE: 0.30). Regarding remission, both remission of MD (b = 0.61, SE: 0.20) and remission of GAD (b = 0.61, 0.26) were significantly associated with an increase in the self-realization/pleasure domain over time. Subsequent Wald tests of the estimates were not significant, indicating symmetric effects.
CONCLUSION: Particularly the remission of GAD and MD was associated with a significant improvement in one of the QoL domains, indicating domain- and trajectory-specific differences. However, symmetric effects observed in this study indicate that gains and losses in QoL associated with remission and incidence of GAD and MD are of similar magnitude in adults aged 50 +.