The Efficacy of Motivational Interviewing as an adjunct to Cognitive Behaviour Therapy for Anxiety Disorders

Recent meta-analytic findings suggest that Motivational Interviewing (MI) used as an adjunct to Cognitive Behavior Therapy (CBT) for anxiety disorders improves overall treatment outcomes (Marker & Norton, 2018). However, when used as a prelude to CBT, MI significantly increases the length of treatment and numerous studies note that the effectiveness of pre-treatment MI subsides over time. The current study adapted an already established 12-session transdiagnostic CBT protocol (tCBT, Norton, 2012) which includes psychoeducation (session 1), cognitive restructuring (sessions 2-3), exposure (sessions 4-9), core belief work (sessions 10-11), and relapse prevention (session 12). The protocol was adapted to include one hour of MI spread across four sessions of tCBT (sessions 1, 3, 8, and 10) at 15 minutes each (min 10 minutes; max 20 minutes). MI strategies were based on the MI for Anxiety Manual by Westra and Dozois (2003). Strategies included a discussion on the pros and cons of change, values and goal exploration, and the elicitation of change talk. MI was used at the start of sessions 1, 3, 8, and 10, and then was followed by CBT. CBT was used in other sessions. All sessions were conducted in an individual format. Sessions were 1 hour in length, and ran weekly for 12 weeks. Treatment also involved Homework requiring approximately 10-15 minutes of participant time per day. Homework was different each week and related to the content of the therapy session e.g. symptom monitoring (week 1), thought diary (week 2-3), exposures (week 4-9), challenging core beliefs (week 10-11). All sessions took place at the Monash FEAR Clinic (Notting Hill, VIC). Therapy was carried out by Clinical Psychology Doctoral students under the supervision of a registered clinical psychologist. All sessions were video recorded and fidelity and treatment integrity was assessed using the Motivational Interviewing Treatment Integrity (MITI) Coding manual. Fidelity was assessed by a postgraduate student blind to treatment condition.