There is an urgent need for an effective psychological treatment for patients with obsessive compulsive disorder (OCD) with poor insight, since this disorder is associated with severe suffering and a low quality of life. The inference based approach (IBA), a new psychotherapy for OCD specifically targets insight in OCD. In a randomized controlled multicentre trial, the effectiveness of IBA was compared to the effectiveness of CBT for treating patients with OCD with poor insight. In this study, 24 sessions of IBA were tested versus 24 sessions of CBT. Ninety patients with a main diagnosis of OCD with poor insight according to the DSM-IV criteria participated in the study. The primary outcome was reduction of the obsessive-compulsive symptoms.

In both conditions, a significant OCD symptom reduction was reached, but no condition effects were established. Post hoc, in a small subgroup of patients with the worst insight (n = 23), it was found that the patients treated with the IBA reached a significantly higher OCD symptom reduction than patients treated with CBT [estimated marginal mean = –7.77, t(219.45) = –2.4, P = 0.017]. Of patients treated with IBA, 41.9% were responder and 20.9% completely recovered. Of the patients treated with CBT, 42.6% were responder and 12.8% recovered.

Patients with OCD with poor insight improve significantly after psychological treatment. The results of this study suggest that both CBT and the IBA are effective treatments for OCD with poor insight. The IBA might be more promising than CBT for patients with more extreme poor insight.

The authors have not supplied their declaration of competing interest.