Trait anxiety levels before and after antidepressant treatment: a 3-wave cohort study.

The aim of this study was to examine change in "trait anxiety" levels assessed repeatedly before and after antidepressant treatment in a large cohort of men and women. A total of 18,732 participants of the Finnish Public Sector Study with no initial record of depression or self-reported doctor diagnosis of depression completed the short form of the Spielberger Trait-Anxiety Inventory in 2000-2002 (T1), 2004-2005 (T2), and 2008-2009 (T3). We used prescription data from the nationwide Drug Prescription Register to identify antidepressant treatment between T1 and T2 (n = 710). Both men (β = 0.435, P < 0.001) and women (β = 0.300, P < 0.001) who received antidepressant treatment had higher trait anxiety levels at T1. Mixed models analyses of repeated measures showed a small but statistically significant decrease in trait anxiety scores for the overall sample of men (β = 0.023, P = 0.033) and women (β = 0.011, P = 0.031) between T1 and T3. The interaction term between time and antidepressant treatment status suggested a greater decrease in trait anxiety levels among men receiving antidepressant treatment, with an adjusted excess decrease in mean trait anxiety scores of 0.163 (P = 0.012) between T1 and T3. We found some evidence suggesting that this is also the case in women, although the evidence in our data was less consistent for women. This large-scale study provides evidence suggesting that antidepressant treatment is associated with a reduction in trait anxiety levels, particularly in men.