The Efficacy and Effectiveness of Online CBT - Jeroen Ruwaard

4.3. Results 734.3 Results4.3.1 RCTEnrollment and randomisation. Recruitment resulted in 164 respondents whoapplied for treatment. Of these, 69 (42%) did not complete the screening. Of theremaining 95 respondents, 37 (39%) met the exclusion criteria (cf. Figure 4.1), and58 were randomly assigned either to immediate treatment (n = 27; 47%) or to thewaiting-list (n = 31; 53%). With these groups sizes, the power of the study to detecta large (d = .8) between-group effect was approximately 71% for the strongest effect.To check the randomization, t-tests and χ 2 tests were conducted with respect to theoutcome measures, gender, age, marital status, education, duration of symptoms, andmedication status. As implied by Table 4.1, no significant differences were found. Weconcluded that the randomisation procedure had been successful.Table 4.1: Characteristics of Participants.ControlTreatmentCharacteristic a n = 31 n = 27DemographicFemale 65% 20 75% 27Age (M, SD) 39 10 38 11Education : tertiary 48% 15 44% 12With partner 55% 17 52% 14SymptomsYears with symptoms (M, SD) 8 7 11 9PDSS-SR > 8 b 52% 16 56% 15MI-AAL > 2.18 c 58% 18 56% 15Panic Diary: at least 1 full-blown attack d 65% 20 67% 18TreatmentPrevious treatment for panic 33% 10 41% 11Previous treatment for other disorder 65% 20 59% 16Medication 29% 9 30% 8a Values represent subsample percentage and size unless otherwise noted.b PDSS-SR: Panic Disorder Severity Scale - Self-Report.c MI-AAL: Mobile Inventory - Avoidance Alone subscale.d A full-blown attack is an attack with four or more core symptoms of panic disorder as listed in the DSM-IV (AmericanPsychiatric Association, 2000)