The purpose aims to assess the efficacy of Brief Culturally Adapted Cognitive Behaviour Therapy (Ca-CBT) for the treatment of Obsessive Compulsive Disorder (OCD).

The presence of obsessions and compulsions characterises obsessive-compulsive disorder (OCD). Obsessions are intrusive, unwanted thoughts, images, or impulses that are distressing and difficult to control. These obsessive thoughts cause significant emotional discomfort. Conversely, compulsions are repetitive behaviours or mental acts performed in response to an obsession or according to rigid rules. These actions are intended to reduce anxiety or prevent a feared event, even though they may not logically connect to the feared outcome. The individual often experiences temporary relief from distress through these ritualistic responses despite their lack of practical relevance to the obsessive fears.

Cognitive Behaviour Therapy (CBT) is widely recognised as a treatment option in both the US and UK National Treatment Guidelines (National Institute for Health and Care Excellence, 2009; American Psychiatric Association, 1993). There is strong evidence supporting CBT's effectiveness in treating, preventing relapse, and managing depression and anxiety (Embling, 2002; Fava et al., 1998; Paykel et al., 1999; Thase, 1997).

However, despite this evidence, there has been limited progress in assessing CBT's effectiveness in low and middle-income countries. CBT may require adaptation in non-Western cultures, as it involves exploring and modifying automatic thoughts and core beliefs (Padesky and Greenberger, 1995).

Preliminary research suggests that treatment manuals based on fundamental CBT principles are effective (Husain et al., 2013; Rahman et al., 2008; Sumathipala et al., 2008; Araya et al., 2003). In Pakistan, an adapted version of CBT for depression was conducted, demonstrating its effectiveness in primary care settings (Naeem et al., 2011). Similarly, a pilot study was conducted on brief culturally adapted cognitive behaviour therapy for obsessive-compulsive disorder (Aslam et al. 2015).

This study aims to conduct a randomised controlled trial using brief culturally adapted cognitive behaviour therapy for obsessive-compulsive disorder in Pakistan, as limited research is available on this aspect. Conducting this trial can provide valuable data on the effectiveness of culturally adapted CBT in the Pakistani cultural setting, informing both local and international practices.

Inclusion Criteria:

• Participants aged 18 years or above
• Participants with at least an elementary level of reading and writing
• Clinical diagnosis of Obsessive Compulsive Disorder, either alone or comorbid with depression or anxiety

Exclusion Criteria:

• Participants with excessive use of alcohol or drugs (using ICD-10 RDC for alcohol or drug abuse or dependence)
• Those with significant cognitive impairment (for example, intellectual disability or dementia)
• Or those with OCD comorbid active psychosis