Background: Despite the growth of reduced therapist-contact cognitive behavioural therapy (CBT) programmes, there have been few systematic attempts to determine prescriptive indicators for such programmes vis-à-vis more standard forms of CBT delivery. The present study aimed to address this in relation to brief (6-week) and standard (12-week) therapist-directed CBT for panic disorder (PD) with and without agoraphobia. Higher baseline levels of severity and associated disability/co-morbidity were hypothesized to moderate treatment effects, in favour of the 12-week programme.
Method: Analyses were based on outcome data from two out of three treatment groups (n=72) from a recent trial of three forms of CBT delivery for PD. The dependent variables were a continuous composite panic/anxiety score and a measure of clinical significance. Treatment x predictor interactions were examined using multiple and logistic regression analyses.
Results: As hypothesized, higher baseline severity, disability or co-morbidity as indexed by strength of dysfunctional agoraphobic cognitions; duration of current episode of PD; self-ratings of panic severity; and the 36-item Short Form Health Survey (SF-36) (Mental component) score were all found to predict poorer outcome with brief CBT. A similar trend was apparent in relation to baseline level of depression. With high and low end-state functioning as the outcome measure, however, only the treatment x agoraphobic cognitions interaction was found to be significant.
Conclusions: While there was no evidence that the above variables necessarily contraindicate the use of brief CBT, they were nevertheless associated with greater overall levels of post-treatment improvement with the 12-week approach.