Zum Umgang Mit Aufdringlichen Gedanken Bei Der Zwangsstörung - Zwei Behandlungsstrategien im Vergleich
Phase: NA
Conditions: Obsessive-Compulsive Disorder
Sponsor: Christoph-Dornier-Stiftung für Klinische Psychologie

Official Title: 
Dealing With Intrusive Thoughts in OCD - a Comparison of Detached Mindfulness and 
Cognitive Restructuring  
 
Date of Document: 
July 12th, 2018 
 
NCT number:  
NCT03002753 
 
 
 
 
 
 
 
 
 
 
 
 
 

Methods 
Study Design 
The study protocol was reviewed and approved of by the ethics committee of the 
Department of Psychology at the University of Münster, Germany. Additionally, the study 
protocol was registered at ClinicalTrials.gov under the ID NCT03002753. All participants 
provided written informed consent after the study procedure had been fully explained. The 
study was conducted between January 2017 and June 2018. The study employed a 
randomized, controlled, waitlist control group design (WLCG). Participants randomized to 
the non-waitlist (NWL) group started their treatment at the beginning of the week following 
Pre1 assessment whereas participants randomized to the waitlist control group (WL) started 
treatment with a delay of two weeks.  
Procedure 
Participants were recruited via postings in social media including OCD-related 
German online platforms as well as via posters in university buildings and flyers that were 
distributed in surrounding psychiatric, neurologic and dermatologic practices and outpatient 
departments as well as in local physicians’ practices. Recruitment also involved repeated 
advertisements in local newspapers and  emails to local psychotherapists. Additionally, some 
patients were recruited via the psychotherapeutic outpatient department of the University of 
Münster.  
Participants received € 30 each for the completion of both pre- and post-assessment as 
well as € 40 for completing follow-up assessment. Moreover, participants in the WL were 
paid additional € 20 for their participation in the second pre-assessment (Pre2). Beyond that, 
participants received an additional amount of € 80 to € 100 for filling in questionnaires of a 
smartphone-based ecological momentary assessment (EMA) study that was run prior to the 

first treatment session and directly after the last treatment session. Results of the EMA study 
will be reported elsewhere. 
Assessment 
A two-step assessment was conducted to check inclusion/exclusion criteria. The first 
step involved a phone screening that was conducted by a graduate student research assistant. 
Second, participants meeting the criteria of the phone screening were invited to an assessment 
session (Pre1) which was conducted by one of six study evaluators. All evaluators were 
Master level psychologists currently participating in an advanced training to become a 
cognitive behavioral psychotherapist. They received special training in diagnosing OCD by 
the investigators. The evaluators were blind with regard to the treatment condition of the 
patient (MCT vs. CT) but could not be blinded in terms of whether the patient was in the WL 
or the NWL condition due to aspects concerning the organization of the study process. Pre1 
assessment comprised about three hours and included, among others, the administration of the 
German versions of the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I, 
Wittchen, Zaudig, & Fydrich, 1997) as well as the German version of Y-BOCS (Hand & 
Büttner-Westphal, 1991). The level of premorbid intelligence was assessed by the Multiple-
choice vocabulary intelligence test (MWT, Lehrl, 2015). Information about demographic 
variables as well as previous pharmacological or psychotherapeutic treatments was collected. 
At the end of the Pre 1 assessment, participants filled in a number of questionnaires 
(described in detail below) - most of which they additionally filled in prior to each treatment 
session to obtain process measures. 
The primary outcome measure was the Y-BOCS total score, followed by several 
process measures described below. The primary outcome measure was assessed at three 
(NWL) or four (WL) time points. Baseline measures were collected during Pre1 assessment 
and, in the WL group, additionally during Pre2 assessment. Post-assessment was conducted 

directly after the last treatment session. A follow-up assessment (FU) was conducted 4 weeks 
after the end of the treatment. During the follow-up period no additional treatment was 
provided, but participants were told and encouraged to further practice the techniques they 
had learned in therapy.    
Inclusion and exclusion criteria 
Inclusion criteria comprised a current primary diagnosis of OCD based on the SCID-I, 
a minimum total score of 16 in the Y-BOCS, a minimum age of 18 years, fluent German 
language skills and a minimum IQ of 80. Exclusion criteria included current suicidality or 
suicidal behavior during the last six months, a current or past diagnosis of bipolar or psychotic 
disorder, a current addictive disorder or a current borderline personality disorder. Also, 
participants were excluded if they were currently undergoing a cognitive-behavioral 
psychotherapeutic treatment focusing on OCD or if they had undergone such a treatment in 
the past 12 months. For patients under medication, it was required that the dose was stable for 
at least eight weeks prior to Pre1 assessment. Patients not meeting these criteria were told to 
contact the investigators when their medication had been stable for at least eight weeks. 
Similarly, patients withdrawing from medication had to be at least eight weeks off their prior 
medication before they entered the study. 
Randomization 
Based on the total Y-BOCS score and the total BDI-II score at baseline (Pre1) as well 
as age and gender, participants were randomized by minimization conducted with MinimPy 
program 0.3 (Mahmoud Saghaei, 2010-2011) with default settings to either the WL or NWL. 
Either following Pre1 (NWL) or following Pre2 assessment (WL), participants were once 
more randomly allocated to the treatment group (MCT/CT) using the same minimization 
procedure as described above. Whereas for NWL, this second randomization was based on 

the Pre1 scores of Y-BOCS and BDI-II, the Pre2 scores were used for the WL. The 
participants were randomly assigned to one of the two therapists, which were the first two 
authors. Both therapists were Master level psychologists at an advanced stage of their clinical 
training to become cognitive behavioral psychotherapist and were supervised by the fourth 
author. 
Treatment 
Treatment in both conditions (MCT/CT) comprised four sessions delivered within two 
weeks. Each session lasted 100 min. It was specified that there had to be two sessions per 
week, with a minimum of one day in between the two weekly sessions. The two treatment 
protocols were manualized by the first two authors following the guidelines of Wilhelm and 
Steketee (2006) for the CT group and of Wells (2011) for the MCT group, respectively. Based 
on the suggestions of the OCCWG, the cognitive therapy proposed by Wilhelm and Steketee 
(2006) focuses on six cognitive domains, which are overimportance of thoughts, control of 
thoughts, overestimation of danger, desire for certainty, responsibility, and perfectionism. As 
overimportance of thoughts refers to thought action fusion and control of thoughts contains 
beliefs about the need to control thoughts - which both are parts of metacognitive models of 
OCD - these domains were explicitly excluded from the CT manual in order to avoid an 
overlap with metacognitive aspects and strategies. Similarly, the MCT manual did not feature 
any references to a conceptual way of dealing with cognitions.  
Adherence and competence ratings 
All treatment sessions were videotaped. For adherence and competence ratings, four 
complete treatments from each therapist (two MCT and two CT, each) were randomly 
selected and then rated by another Master level psychologist on a 5-point Likert scale. The 
rater was at an advanced stage of his training to become a cognitive behavioral 
psychotherapist and was not otherwise involved in the study.     

Cognitive Therapy (CT) 
The first session of the CT condition consisted of psychoeducation about 
characteristics of OCD (e. g. the fact that obsessive thoughts are ubiquitous and therefore not 
the actual problem) and comprised the development of an individual cognitive model based 
on the model of (Salkovskis, 1985b, 1999). Focusing on the patient’s individual obsessive-
compulsive symptoms, the model was designed to explain the disorders’ maintenance via the 
distorted appraisals of intrusions, which should therefore be questioned and altered. During 
the second session typical cognitive distortions occurring in OCD were explained 
(overestimation of danger, desire for certainty, responsibility and perfectionism) and 
strategies to question and modify these appraisals were provided and trained, drawing from 
Socratic questioning and logical and hedonistic strategies of disputation. Depending on the 
appraisal at hand, this would for instance include techniques such as multiplication of 
probabilities, distribution of responsibility, cost-benefit analysis, etc., whereas the whole 
process of questioning was recorded in writing. Prior to and after each questioning phase, the 
patient was asked to rate his/her level of conviction concerning the original appraisal. 
Additionally, s/he was encouraged to develop an alternative cognition and to practice this new 
cognition in everyday life. During the third session and the first part of the fourth session, 
these strategies were further trained. The last part of the fourth session consisted of 
summarizing the new knowledge and the techniques the patient had acquired during therapy. 
Homework during therapeutic sessions comprised monitoring and documenting obsessive 
thoughts and dysfunctional appraisals as well as engaging in the active questioning of the 
latter and practicing alternative cognitions in everyday life.  
Metacognitive Therapy (MCT) 
The first session of the metacognitive treatment condition comprised the same 
psychoeducation as in the CT treatment. Afterwards, therapist and patient developed an 

individual metacognitive model of the patient’s obsessive-compulsive symptoms (based on 
Wells, 2011), explaining the maintenance of the disorder via the mechanism of assigning 
obsessive thoughts too much importance and meaning. That is, in contrast to the CT 
condition, patients were taught that it is about their general attitude towards their obsessions, 
not about any specific appraisals in response to their obsessions. During the second session, 
therapist and patient developed a list of the most prominent obsessions, rating each 
obsession’s frequency and its level of distress. This was followed by introducing the strategy 
of DM using different examples and metaphors and finally by training DM applying the 
suggestions by (Wells, 2011). Training DM usually involved the patients closing their eyes 
and following the therapist’s standardized instructions to visualize an obsession, to dissociate 
oneself from the obsession and to switch to a mode of passive observing instead of active 
interaction. The third session and the first part of the fourth session were made up by further 
DM training. The last part of the fourth session was identical to the CT condition. Homework 
between therapeutic sessions comprised monitoring and documenting obsessive thoughts 
(only between sessions 1 and 2) and exercising DM several times per day. 
Process Measures 
Prior to each treatment session, participants completed the following questionnaires: 
German equivalent of the self-rating version of the Y-BOCS (Baer, 1993), German version  
(Gönner, Leonhart, & Ecker, 2007) of the Obsessive-Compulsive Inventory-Revised (Foa et 
al., 2002), German version (Ertle et al., 2008) of the Obsessive-Beliefs Questionnaire 
(Obsessive Compulsive Cognitions Working Group, 2005), German translation of the 
Thought-Fusion Instrument (Wells, Gwilliam, & Cartwright-Hatton, 2002), German 
translation of Beliefs About Rituals Inventory (Wells & McNicol, 2004), German translation 
of Stop Signals Questionnaire (Myers, Fisher, & Wells, 2009) and the German version of 
Beck Depression Inventory Revised (Hautzinger, Keller, & Kühner, 2006). German version 

of Personality Inventory for DSM-5 (Krueger, Derringer, Markon, Watson, & Skodol, 2013) 
was assessed at Pre1. Study measures showed good to very good psychometric properties. 
The questionnaires were presented on a tablet computer using a web-based online-survey 
software (www.unipark.de). Results of the process measures will be reported elsewhere. 
Homework Rating. During each session, homework compliance was rated by the 
therapist on a 7-point rating scale ranging from 0 (no homework implemented) to 7 
(homework done exactly as the patient was told). These results will be reported elsewhere.