The efficacy of the Inference Based Approach, a new cognitive therapy for patients with the Obsessive Compulsive Disorder with poor insight.

Obsessive-Compulsive Disorder (OCD) is a severe, often chronic disorder which
is diagnosed when either obsessions or compulsions are present and when these
symptoms cause marked distress and interfere with work or social functioning.
OCD is a severe chronic psychiatric disorder, which affects 1-3% of the adult
population and belongs to the 10 most invalidating medical conditions in the
industrialized world (Bebbington 1998, Eisen et al. 2006, Karno et al. 1988,
Kessler et al. 2005).
Evidence-based treatments for OCD consist of cognitive-behavioral therapy and
antidepressants. Of patients with OCD who start with these treatments and are
able to complete them, only 25-50% reaches complete recovery of the disorder
(Fischer and Wells 2005; van Oppen et al, 2005). Another major clinical problem
is that about 40% of the patients prematurely drop out from treatment or refuse
treatment beforehand (Stetekee, 1993). One of the clinical most important
predictors of poor outcome is the subgroup of patients with OCD with 'poor
insight' (Himle et al, 2006, Tolin et al 2004, 2001, Kishore et al, 2003, Tot
et al 2003, Erzegovesi et al 2001).

The objective of this study is to improve the prognosis of patients with the
Obsessive Compulsive Disorder (OCD), with poor insight. A psychological
treatment, the Inference Based Approach (IBA), which is developped and has been
proven effective in Canada, will be introduced and evaluated in the
Netherlands. In this project IBA will be implemented at the outpatient
treatment centres of the Marina de Wolf institute of Meerkanten GGZ and of the
stichting Buitenamstel de Geestgronden.
The main question to be answered is: do patients with OCD with poor insight
improve more from IBA than from cognitive behavioral therapy?

The study design is a randomized controlled effectiveness study (RCT) of 20
weeks with patients with OCD with poor insight. In this study the effectiveness
of IBA will be compared with a control condition in which patients will be
treated with cognitive behavioral therapy.

After screening the participants will be randomly allocated to a treatment with
IBA or the control condition which contains of cognitive behavioral therapy.
IBA differs from the standard treatment because within this model specific
attention is given to the credibility of the obsession and not only to the
appraisal of it. The central idea of this new treatment form is that OCD
patients with poor insight perform poor on reality testing (when they are
obsessing) and that they treat imagined dangers as real instead of imagined
dangers. The treatment teaches the patients to differentiate that imagination
always precedes their compulsions. The learn how to distinguish imagination and
reality better.
The control treatment consists of cognitive behavioral therapy.
The therapists are trained in a 5-day workshop by the team of O'Connor, the
founder of IBA, and will be supervised by them. The IBA-protocol (O'Connor,
Aardema & Pelissier, 2005) will be translated for this study. The therapists
did participate in a pilot study and will be supervised weekly.

There is no risk associated with participating in the study, except time
investment. This is, including measurement at follow up 4 hours per patient.