Obsessive compulsive disorder (OCD) is characterised by obsessions, compulsive behaviours, or both. New developments in the treatment of OCD involve medications that work in conjunction with cognitive behavioural therapy (CBT), the most promising of which is D-cycloserine. OCD could be placed in a new classification of its own when mental health nomenclature is revised in future years*. The issues around this severe and disabling condition are discussed in a Seminar in this week's edition of the Lancet, written by Dr Jonathan S Abramowitz, University of North Carolina, Chapel Hill, NC, USA, and colleagues.
OCD has a lifetime rate of 2—3% in the general population—and is a symptomatically heterogeneous condition, in which various different kinds of obsessions and compulsions exist. However, research indicates that certain obsessions and compulsions tend to co-occur to form five main dimensions: (i) obsessions about being responsible for causing or failing to prevent harm; checking compulsions and reassurance-seeking; (ii) symmetry obsessions, and ordering and counting rituals; (iii) contamination obsessions, and washing and cleaning rituals; (iv) obsessions concerning sex, violence, and religion; (v) hoarding, which are obsessions about acquiring and retaining objects, and associated collecting compulsions.
Two common features of OCD—excessive doubting and repetitive actions—suggest that specific brain regions are involved in the condition. People with OCD are more likely to have first-degree family members who suffer from the same disorder than are matched controls who are more likely to have first-degree family members who do not have the disorder. Twin studies of adults suggest that obsessive-compulsive symptoms are moderately heritable, with genetic factors contributing 27-47% of variance in scores on measures of obsessive-compulsive symptoms. The remaining 53-73% of the variance is attributed to environment factors.
Some experts argue that OCD should be moved into its own class in the forthcoming revisions to diagnostic manuals (made by a working group of experts from around the world—The American Psychiatric Association spearheads the effort)—but there is considerable disagreement, on both conceptual and empirical grounds. Randomised controlled trials have indicated that drug therapies for obsessive-compulsive disorder include serotonin reuptake inhibitors, such as clomipramine, and some selective serotonin reuptake inhibitors. Recent studies have shown D-cycloserine to be a promising compound for extinguishing the fear connected to OCD more quickly than placebo when combined with the psychological intervention of exposure and response prevention (behavioural) therapy. Exposure entails systematic, repeated, and prolonged confrontation with stimuli that provoke anxiety and the urge to perform compulsive rituals. In situational exposure, the patient encounters actual feared stimuli—eg, toilets, cemeteries, and knives. In imaginal exposure, the patient confronts anxiety provoking obsessional images, thoughts (eg, of a loved one's death), and doubts (eg, "I might have hurt an innocent person by mistake"). Response prevention means refraining from performing compulsive rituals. For example, a patient who fears the number 13 because it will bring bad luck would practice writing this number and imagining causing bad luck. He or she would also refrain from performing any rituals to reduce anxiety or the chances of bad luck (eg, saying prayers, checking for reassurance). The aim of exposure and response prevention, which is the most effective long-term treatment for OCD, is to teach patients that obsessional anxiety does not persist indefinitely, and that avoidance behaviour and compulsive rituals are unnecessary for averting harm. Another possible intervention is deep brain stimulation of the basal ganglia, through surgically implanted electrodes—this needs to be tested for safety and efficacy.
The authors conclude: "Despite some promising models, what causes obsessive-compulsive disorder remains unknown. A combination of cognitive and neurobiological factors might be needed to fully explain the disorder... Some have suggested that OCD should be regarded as the centre of a new diagnostic category of obsessive-compulsive-related disorders...however, this proposal is controversial. Further research is needed to determine whether such a reclassification of the disorder would improve the understanding of the causes and treatment of this severe, debilitating, and chronic disorder."
Dr Jonathan S Abramowitz, University of North Carolina, Chapel Hill, NC, USA. T) 1-919-843-8170 E) jabramowitz@unc.edu
For full Seminar, see: http://press.thelancet.com/ocdfinal.pdf
Note to editors: * there are two diagnostic rulebooks for psychiatric disorders, DSM IV (run by the American Psychiatric Association) and ICD 10 (WHO). Both are currently being revised, but the new versions (DSM V and ICD 11) are not expected to be published for several years.
Journal
The Lancet