Family-based cognitive behavioural therapy versus family-based relaxation therapy for obsessive-compulsive disorder in children and adolescents: protocol for a randomised clinical trial (the TECTO trial)
Authors: Pagsberg Anne Katrine , Uhre Camilla , Uhre Valdemar , Pretzmann Linea , Christensen Sofie Heidenheim , Thoustrup Christine , Clemmesen Iben , Gudmandsen Amanda Aaen , Korsbjerg Nicoline Løcke Jepsen , Mora-Jensen Anna-Rosa Cecilie , Ritter Melanie , Thorsen Emilie D. , Halberg Klara Sofie Vangstrup , Bugge Birgitte , Staal Nina , Ingstrup Helga Kristensen , Moltke Birgitte Borgbjerg , Kloster Anne Murphy , Zoega Pernille Juul , Mikkelsen Marie Sommer , Harboe Gitte Sommer , Larsen Katrin Frimann , Clemmensen Line Katrine Harder , Lindschou Jane , Jakobsen Janus Christian , Engstrøm Janus , Gluud Christian , Siebner Hartwig Roman , Thomsen Per Hove , Hybel Katja , Verhulst Frank , Jeppesen Pia , Jepsen Jens Richardt Møllegaard , Vangkilde Signe , Olsen Markus Harboe , Hagstrøm Julie , Lønfeldt Nicole Nadine , Plessen Kerstin Jessica 
Published: March 2022

Abstract
Background
Cognitive behavioural therapy (CBT) is the recommended first-line treatment for children and adolescents with obsessive-compulsive disorder (OCD), but evidence concerning treatment-specific benefits and harms compared with other interventions is limited. Furthermore, high risk-of-bias in most trials prevent firm conclusions regarding the efficacy of CBT. We investigate the benefits and harms of family-based CBT (FCBT) versus family-based psychoeducation and relaxation training (FPRT) in youth with OCD in a trial designed to reduce risk-of-bias.

Methods
This is an investigator-initiated, independently funded, single-centre, parallel group superiority randomised clinical trial (RCT). Outcome assessors, data managers, statisticians, and conclusion drawers are blinded. From child and adolescent mental health services we include patients aged 8–17 years with a primary OCD diagnosis and an entry score of ≥16 on the Children’s Yale-Brown Obsessive-Compulsive Scale (CY-BOCS). We exclude patients with comorbid illness contraindicating trial participation; intelligence quotient < 70; or treatment with CBT, PRT, antidepressant or antipsychotic medication within the last 6 months prior to trial entry. Participants are randomised 1:1 to the experimental intervention (FCBT) versus the control intervention (FPRT) each consisting of 14 75-min sessions. All therapists deliver both interventions. Follow-up assessments occur in week 4, 8 and 16 (end-of-treatment). The primary outcome is OCD symptom severity assessed with CY-BOCS at end-of-trial. Secondary outcomes are quality-of-life and adverse events. Based on sample size estimation, a minimum of 128 participants (64 in each intervention group) are included.

Discussion
In our trial design we aim to reduce risk-of-bias, enhance generalisability, and broaden the outcome measures by: 1) conducting an investigator-initiated, independently funded RCT; 2) blinding investigators; 3) investigating a representative sample of OCD patients; 3) using an active control intervention (FPRT) to tease apart general and specific therapy effects; 4) using equal dosing of interventions and therapist supervision in both intervention groups; 5) having therapists perform both interventions decided by randomisation; 6) rating fidelity of both interventions; 7) assessing a broad range of benefits and harms with repeated measures.
The primary study limitations are the risk of missing data and the inability to blind participants and therapists to the intervention.

Trial registration
ClinicalTrials.gov: NCT03595098, registered July 23, 2018.