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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Retrospectively registered

Titles & IDs
Public title
The Efficacy of Motivational Interviewing as an adjunct to Cognitive Behaviour Therapy for Anxiety Disorders
Scientific title
The Efficacy of Motivational Interviewing as an adjunct to Cognitive Behaviour Therapy for Anxiety Disorders
Secondary ID [1] 299378 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Anxiety Disorders 314544 0
Condition category
Condition code
Mental Health 312889 312889 0 0

Study type
Description of intervention(s) / exposure
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.
Intervention code [1] 315641 0
Intervention code [2] 315798 0
Treatment: Other
Comparator / control treatment
The control condition also received tCBT as per the tCBT manual, psychoeducation was added at sessions 1, 3, 8, and 10 for 15 minutes to control for therapist time.
Control group

Primary outcome [1] 321494 0
Anxiety Disorder Interview Schedule for DSM-5 Clinician Severity Rating
Timepoint [1] 321494 0
Immediately Post Treatment (week 12)
Secondary outcome [1] 375135 0
Clinical Global Impressions - Severity (symptom severity)
Timepoint [1] 375135 0
Immediately Post-Treatment (week 12)

Key inclusion criteria
DSM-5 Principal Anxiety Disorder Diagnosis
18 years or older
Adequately proficiency in English to participate in treatment
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Dementia or other neurocognitive disorders that could impair their ability to provide informed consent or actively engage in treatment
Serious suicidality, substance use requiring detoxification, or any other condition that warranted immediate intervention

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Block randomisation using coin toss
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people assessing the outcomes
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Hierarchical linear modelling
36 participants, 18 in each group.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 28110 0
3800 - Monash University

Funding & Sponsors
Funding source category [1] 303893 0
Government body
Name [1] 303893 0
Australian Government Research Training Program (RTP) Scholarship
Address [1] 303893 0
Department of Education and Training
GPO Box 9880
Canberra ACT 2601
Country [1] 303893 0
Primary sponsor type
Monash University
Wellington Rd,
Clayton VIC 3800
Secondary sponsor category [1] 304042 0
Name [1] 304042 0
Address [1] 304042 0
Country [1] 304042 0

Ethics approval
Ethics application status
Ethics committee name [1] 304399 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 304399 0
Wellington Rd,
Clayton VIC 3800
Ethics committee country [1] 304399 0
Date submitted for ethics approval [1] 304399 0
Approval date [1] 304399 0
Ethics approval number [1] 304399 0
CF15/3829 - 2015001674

Brief summary
The purpose of this study was to ascertain whether adapting transdiagnostic-CBT to include intermittent MI outperforms transdiagnostic-CBT alone in anxiety disorder populations.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 96810 0
Prof Peter Norton
Address 96810 0
18 Innovation Walk
Monash University
Clayton, VIC 3800
Country 96810 0
Phone 96810 0
+61 3 9905 1709
Fax 96810 0
Email 96810 0
Contact person for public queries
Name 96811 0
Dr Isabella Marker
Address 96811 0
18 Innovation Walk
Monash University
Clayton, VIC 3800
Country 96811 0
Phone 96811 0
+61 3 9902 4480
Fax 96811 0
Email 96811 0
Contact person for scientific queries
Name 96812 0
Prof Peter Norton
Address 96812 0
18 Innovation Walk
Monash University
Clayton, VIC 3800
Country 96812 0
Phone 96812 0
+61 3 9905 1709
Fax 96812 0
Email 96812 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
Confidential patient information
What supporting documents are/will be available?
Ethical approval
How or where can supporting documents be obtained?
Type [1] 5038 0
Ethical approval
Citation [1] 5038 0
Link [1] 5038 0
Email [1] 5038 0
Other [1] 5038 0
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Other publication details
Citation type [1] 5039 0
Conference abstract
Citation/DOI/link/details [1] 5039 0
Marker, I. & Norton, P. J. (2019, July). Can intermittent Motivational Interviewing increase
the efficacy of CBT in anxiety disorders? Poster at the 9th World Congress of
Behavioural and Cognitive Therapies, Berlin, Germany.
Results – basic reporting
Results – plain English summary
Results suggested that intermittent Motivational Interviewing (MI) and transdiagnostic Cognitive Behaviour Therapy (tCBT) outperform tCBT on self-report anxiety measures, and perform similarly on clinician rated anxiety measures.