2.7. Therapists

Treatment was provided by 60 therapists (91.7% female; 98.1% of Dutch origin) across 16 sites. Therapists were aged 24–63 years (M = 42.38, SD = 10.89) and had 2–40 years (M = 13.54, SD = 9.04) of working experience. Most therapists (95.0%) were licensed psychologists with one or more clinical registrations. Two therapists were in training to become cognitive therapists and one therapist was a psychiatric nurse trained as a cognitive therapist. They each treated between one and six participating adolescents. Therapists in the face-to-face CBT and blended CBT condition received a two-day training in delivering the protocolized treatment by a registered clinical psychologist. Therapists in the treatment as usual condition received instruction not to use CBT. Age and level of experience of therapists were evenly distributed across the treatment conditions.