Differential predictors of response to preventive cognitive therapy in recurrent depression: a 2-year prospective study

BACKGROUND: Major depressive disorder is a recurrent disease. Brief cognitive therapy (CT), added to either regular care or medication, is helpful in preventing relapse/recurrence. Little is known which type of persons benefit from preventive CT, the so called 'aptitude treatment interaction' effect. METHOD: The present cohort included exclusively patients with at least two previous episodes remitted on various types of treatments (n = 172). They were assessed within a clinical trial comparing treatment as usual (TAU) with preventive CT added to TAU. Differential demographic, illness-related, psychological and biological risk factors in postponing recurrence by preventive CT were examined. RESULTS: Significant aptitude-treatment-interaction effects were found for the number of previous episodes, daily hassles and life events, avoidant coping, gender, and morning cortisol levels. Preventive CT seemed ineffective in patients with life events (as more frequently reported by women in our study) and in patients with high episode number characterized by higher levels of avoidant coping. Generic predictors indicate that in CT, as in TAU, patients with more residual depressive symptomatology and higher levels of dysfunctional attitudes profit less from preventive CT. CONCLUSION: The finding that preventive CT protects against the influence of a consistently found risk factor of relapse/recurrence, i.e. the number of depressive episodes, underlines the potential of psychological preventive interventions. Preventive CT seemed to be especially effective in reducing presumably internally provoked, relapse/recurrence but may be quite ineffective in reducing externally provoked relapse/recurrence. CT possibly prevents either stress generation or disrupts kindling effects. Kindling effects probably cannot be disrupted in patients with higher levels of avoidant coping who experienced a high number of episodes, and patients who experienced life event