Overlap of obsessive compulsive and psychosis risk symptoms in a specialized clinic.

Aim: Psychotic disorders and obsessive-compulsive disorder (OCD) commonly co-occur. Likewise, subthreshold psychosis symptoms (clinical high risk for psychosis; CHR) and obsessive compulsive symptoms (OCS) often overlap and may be difficult to differentiate. This study aimed to replicate research investigating the prevalence of OCD in a CHR clinic sample, validate and investigate factor structure of a self-report OCS measure in a CHR sample, explore how OCS may relate to CHR and co-occurring symptoms, and investigate whether real-world CHR treatment improves OCS and CHR symptoms.

Method: This study analysed archival clinical data from baseline and 6-month follow-up assessments collected by a specialist outpatient CHR clinic. Data included assessments of CHR symptoms, OCS, and clinician-rated diagnosis. Exploratory factor analysis examined the OCS measure.

Results: Within this CHR clinic sample, 13.5% experienced co-morbid OCD. The self-report OCS measure had two factors: (1) checking and counting behaviours and (2) intrusive thoughts and images of harm/guilt. The checking and counting factor correlated with depression and social anxiety. The intrusive thoughts and images of harm/guilt factor significantly correlated with unusual thought content and social anxiety. Between baseline to 6-month follow-up, clients exhibited CHR symptom improvement regardless of OCD diagnosis. However, OCS did not change.

Conclusions: These findings support validity of a self-report OCS measure in a CHR clinic sample and that types of OCS experiences may exhibit different clinical patterns. Additionally, it appears that individuals with comorbid OCD responded similarly to CHR treatment compared to those without OCD.