Temporal stability of symptoms of affective disorders, cognitive vulnerability and personality over time

Signs and symptoms of psychopathology can be chronic but are generally regarded as less stable over time than markers of cognitive vulnerability and personality. Some findings suggest that these differences in temporal stability are modest in size but a rigorous examination across concepts is lacking. The current study investigated the temporal stability of affective symptoms, cognitive vulnerability markers and personality traits at various assessments over nine years.

Participants of the Netherlands Study of Depression and Anxiety were assessed at baseline and reassessed after 2, 4, 6 and 9 years. They were grouped on the basis of waves of depression and anxiety CIDI-diagnoses into stable healthy (n = 768), stable patients (n = 352) and unstable patients (n = 821). We determined temporal stability by calculating intraclass correlation coefficients (ICC) and consistency indices of latent state-trait analyses (LST).

Temporal stability was moderate to high for symptoms (range ICC's 0.54-0.73; range consistency 0.64-0.74), cognitive vulnerability (range ICC's 0.53-0.76; range consistency 0.60-0.74) and personality (range ICC's 0.57-0.80; range consistency.60 -0.75). Consistency indices for all measures were on average a bit lower in the unstable group (ICC = 0.54) compared to the stable groups (ICC = 0.61). Overall stability was similarly high after 2, 4, 6 and 9 years.

The 9-year stability over time of symptoms of affective disorders and that of indices of cognitive vulnerability and personality are remarkably similar and relatively high.