In this episode, Professor David Veale and I explore OCD, intrusive thoughts, compulsions, avoidance, reassurance seeking, and how OCD is treated. We discuss what OCD is, why intrusive thoughts become powerful, how obsessions often attach to the things people value most, and why OCD is not simply being tidy, clean, or perfectionistic. Professor Veale explains different forms of OCD, including contamination fears, responsibility for harm, unacceptable sexual or violent thoughts, religious fears, ordering, checking, and relationship OCD. We also discuss CBT, exposure and response prevention, tolerating uncertainty, and why reassurance can make OCD worse by feeding doubt and undermining confidence. Professor Veale explains how family members can support someone with OCD without reinforcing compulsions, the role of SSRIs, how OCD can overlap with autism, ADHD and trauma, and how body dysmorphic disorder relates to OCD. Finally, we talk about good quality therapy, newer treatments, lifestyle factors such as sleep, exercise and connection, and why OCD is a treatable condition.