The Efficacy and Effectiveness of Online CBT - Jeroen Ruwaard

4.4. Discussion 79the time variable and the other variables, i.e. time by pre-treatment symptom severity,by gender, by education, MI-AAL, and by medication status.With regard to the PDSS-SR, none of the interaction terms were significant. Hence,the model was simplified to include only the main effects. In this model, medicationstatus [t(50) = 2.0; P = .05] and education [t(50) = 0.3; P = .76] had no effects.However, PDSS-SR pretest scores [t(50) = 5.7; P < .001] and gender [t(50) = 3.0; P= .019] predicted post-treatment symptoms significantly. Post treatment scores werehigher for females, and for those displaying higher symptoms levels at pretest.With regard to attack frequency, only the interaction of time and pre-treatmentseverity was significant [t(50) = 3.8; P < .001], signalling a significant larger declinein the number of panic attacks at follow-up compared to the posttest in those experiencingmore attacks at pretest. In the reduced model, in which we retained only thisinteraction and the main effects, none of the variables predicted post-treatment scoressignificantly, including gender and pre-treatment agoraphobic avoidance (MI-AALscores).Given the regression results, we further explored the effect of pretest symptomseverity. Based upon the PDSS-SR baseline score, we split the sample into two groups(based on the PDSS-SR cut-off of 8) and determined the effect size for each groupon this measure. This revealed considerable higher effects in the group with higherpretest levels (posttest d = 2.1; follow-up d = 2.3).4.4 DiscussionIn comparison to a waiting-list, web-based therapist-assisted CBT induced moderate tolarge reductions in panic symptoms and general psychopathology in a heterogeneouscommunity sample of clients suffering from chronic symptoms of panic disorder.Treated participants were six times more likely to experience a reduction in panicattacks of at least 50%. Client satisfaction was high. After three years, even thoughthe participants never met their therapist, 80% returned for follow-up measurements.On the long term, improvements were found to be more pronounced.