Chronic environmental stress and the temporal course of depression and panic disorder: A trait-state-occasion modeling approach.

Both acute stressful life events and ongoing strains are thought to confer vulnerability to emotional disorders. Unremitting stressful conditions may be particularly pathogenic, but prior research has struggled to delimit chronic versus transient stressful experiences. We aimed to isolate stable stressors-theorized to be indicators of a latent stress proneness trait-and to examine their effects on the temporal course of depression and panic disorder. We recruited 677 patients diagnosed with an emotional disorder and administered interviews for psychopathology and life stress 3 times over 12-month intervals. Trait-state-occasion modeling revealed that 74% of the variance in life stress was stable over the follow-up period. These stable stressors were associated with a more refractory course of depression and, to a smaller degree, panic disorder over time. In addition, neither gender nor participation in cognitive-behavioral therapy affected the persistence of environmental stress over the study time frame. We discuss implications of these findings for explaining depression recurrence, improving psychological interventions for emotional disorders, and the measurement and evaluation of stress proneness.