Regression Trunk Approach we found that locus of control orientation (LOC) predicted the differential effectiveness of cognitive therapy. Those patients with a medium internal LOC who received cognitive therapy performed significantly better than all patients who received a placebo pill on 8 of the 10 outcome variables. We did not find a differential LOC effect for antidepressant treatment. No evidence for aptitude-treatment interactions using hierarchical multiple regression analysis was

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... Conclusions: Moderately strong beliefs about self-control of panic disorder congruent with the cognitive intervention provided seem to moderate treatment effectiveness. Future studies must be more attentive to the nonlinear effects of patient characteristics on the outcome of different types of treatments.