In their influential theory of personality and depression, Clark & Watson (1999, Clark et al. 1994) posited that depressive disorders are characterized by high levels of N/NE and low levels of E/PE. A large number of cross-sectional studies have evaluated these relations as well as the links between depression and the other FFM dimensions. Kotov et al. (2010) recently conducted a meta-analysis of this literature, which revealed that MDD is associated with very high N/NE (Cohen’s d =1.33) and low conscientiousness (d =−0.90). The link to low E/PE was more modest (d =−0.62) and inconsistent, with some studies finding positive effects. The associations with the other two traits were weak and unremarkable. The N/NE finding is consistent with expectations, but the effect for E/PE was smaller and that for conscientiousness was larger than anticipated. Dysthymic disorder exhibited a more extreme profile with remarkably strong and consistent links to E/PE (d =−1.47), N/NE (d =1.93), and conscientiousness (d =−1.24). This is not surprising as dysthymic disorder is thought to be more trait-like than MDD, and a greater contribution from personality might be expected.
