Obsessive Compulsive Disorder (OCD) is a common psychological condition that I see frequently in my work as a therapist in Edinburgh. A diagnosis of OCD is made when a person shows the two key features of obsessions and compulsions. An obsession is a persistent thought, image, or urge that seems to enter the mind from nowhere and causes significant distress. Compulsions are things done again and again in response to an obsession or obsessions, in an attempt to reduce the stress. Compulsions are usually physical acts (such as washing the hands excessively or repeatedly checking door locks), but they can also be mental acts.

As a therapist in Edinburgh I see a lot of clients suffering from OCD, and I am frequently asked what causes it. Unfortunately the causes of OCD are not known for sure, but there are some likely culprits and I give a brief summary of these in this article.

Genetic factors seem likely to play some role in a person developing OCD. If you have a "first-order" relative with OCD (that is, a parent or sibling has OCD), then your chance of developing OCD yourself is in the region of 5%. However, it should be noted that OCD affects about 1% of the general adult population in the West, so an increased risk is present but it certainly isn't enormous.

Subtle abnormalities in the brain have also been put forward as causes of OCD, but this has not been well supported by the research to date. Brain scans do not show any structural abnormality, and the more recent "functional" scan results (e.g. showing high frontal lobe activity) probably reveal the brain's response to OCD, rather than being the cause of OCD.

It has been hypothesised that a key element underlying OCD is a relative lack of the neurochemical serotonin in certain parts of the brain. The only evidence for this has been the fact that OCD seems to respond (at least sometimes) to the SSRI class of antidepressants (SSRI meaning Selective Serotonin Reuptake Inhibitor - these drugs increase the amount of serotonin in the brain). Obviously the fact that some condition improves when a medicine is taken does not mean that the medication is acting on the cause of the condition. If you break your leg and are in severe pain, morphine will reduce the pain but it will have no affect on the cause of that pain!

One of the more interesting theories about the causes of OCD has been related to sufferer's memories. This theory postulated that OCD sufferer's may have poor memories and that is why they repeat their compulsions so frequently! In reality, OCD sufferer's memories are fine but they don't seem to trust them as well as other people do.

A final focus of research in OCD has been the apparent "triggering" of the condition. OCD commonly starts in the late teens and early twenties, and often seems to follow on from some form of emotional, psychological or physical stress. Common stresses include pregnancy and childbirth, physical violence, bullying, bereavement, or even the change of job or role at home. Whilst such "triggers" are common, they are not ubiquitous and a significant minority of people I see as a therapist in Edinburgh develop OCD without any identifiable stress.

So, in summary, the cause or causes of OCD remain obscure and more research needs to be done. However, even without definite causes being known, there are well-researched and effective treatments for OCD. As mentioned above, SSRI drugs are commonly used to help OCD sufferers, but the most effective treatment is Cognitive Behavioural Therapy, or CBT. This is the treatment of choice recommended by NICE (the Institute of Clinical Excellence - a Government body that advises clinicians about the safety and efficacy of different treatments for illness). Please see my other articles for more information about CBT in Edinburgh.

Dr Steve Last is a Psychiatrist and therapist in Edinburgh who uses CBT techniques to treat common psychological problems such as depression, anxiety and OCD. Please visit http://www.drstevelast.co.uk for more information about psychological problems and CBT.