Obsessive-compulsive disorder (OCD) has been recently drawn apart from anxiety disorder by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5) and clustered together with related disorders (eg, hoarding, hair pulling disorder, skin picking), which with it seems to share clinical and neurophysiological similarities. Recent literature has mainly explored brain circuitries (eg, orbitofrontal cortex, striatum), molecular pathways, and genes (eg, Hoxb8, Slitrk5, Sapap3) that represent the new target of the treatments; they also lead the development of new probes and compounds. In the therapeutic field, monotherapy with cognitive behavioral therapy (CBT) or selective serotonin reuptake inhibitors (SSRIs) is recommendable, but combination or augmentation with a dopaminergic or glutamatergic agent is often adopted. A promising therapy for OCD is represented by repetitive transcranial magnetic stimulation (rTMS), which is suitable to treat compulsivity and impulsivity depending on the protocol of stimulation and the brain circuitries targeted.

Obsessive-compulsive symptoms (OCS) are a common phenomenon in patients with schizophrenia and are associated with additional clinical and functional impairments. So far treatment approaches have been limited to mainly pharmacological interventions with restricted effectiveness. Because cognitive behavioural therapy (CBT) is considered treatment of first choice for patients with primary obsessive-compulsive disorder (OCD), it seems compelling to consider it as a treatment option for comorbid OCS in schizophrenia. This research was conducted in order to investigate the theoretical and empirical basis for CBT in the treatment of comorbid OCS/OCD in schizophrenia. A comprehensive review and analysis of published literature was performed. Outcome measures from case-reports and a case-series showed favourable results with a significant reduction of symptom severity in 24/30 patients treated with CBT and exposure and response prevention (ERP) or ERP alone. CBT appears to offer a valuable opportunity to reduce symptom severity in this highly impaired group of patients. Based on these results and with a strong focus on tolerability concerns, suggestions for possible CBT approaches for the comorbid group are proposed. Further research within this field and systematic clinical evaluations are highly desirable.