There are several types of obsessive-compulsive disorders (OCD), ranging from intrusive thoughts/behaviours and body dysmorphic disorder, all the way to the compulsion to pull hair (trichotillomania). The main criterion for OCD listed in DSM-5 is the: presence of obsessions, compulsions, or both.
There are several brain areas associated with OCD. Diagnosed OCD patients have greater activity in the in the anterior cingulate cortex, orbitofrontal cortex, caudate and thalamus (the parts of the brain involved in action monitoring, amongst other things).
There are also certain hormones associated with having OCD, for example, people who believe they’re in love, also score highly on an OCD questionnaire, this because cortisol (the stress hormone) increases, but completing the obsessive-compulsive task causes levels of serotonin (the happy hormone) to increase too; therefore, suggesting being in love is chemically similar to having OCD.
The treatments for OCD are vast, with some patients responding quite well to certain drug treatments, especially the serotonin-selective reuptake inhibitors (SSRIs), and some responding better to cognitive-behavioural therapy. The best results have combined the two processes. Treatment for OCD focuses on cognitive restructuring, breaking down the irrational belief system that has built up around the obsession, using self-report techniques to control anxiety.
Obsessions: are recurrent and persistent thoughts, urges, or images that are intrusive and unwanted, they usually cause anxiety or distress.
Compulsions: are repetitive behaviours (e.g., hand washing) or mental acts (e.g., counting) aimed at preventing or reducing anxiety or distress