Mental health articles

Genetic factors

Evidence of a genetic risk for OCD is mixed. Carey and Gottesman (1981) reported an 87 per cent concordance between MZ twins and a 47 per cent concordance for DZ twins, implying a part genetic explanation for risk of the disorder. By contrast, Andrews et al. (1990) found no evidence of higher concordance in MZ than in DZ twins. Similarly, Black et al. (1992) found 2.5 per cent of their large sample of relatives of people with OCD had the disorder: a fi gure not dissimilar to the 2.3 per cent prevalence among their control group and population norms. Biological studies have met a similar impasse: Samuels (2009) recently concluded that despite several candidate genes being investigated, specifi c genes causing OCD have not been identifi ed.

Biological mechanisms

Biological theorists (e.g. Christian et al. 2008) have identifi ed two interconnected brain systems that are implicated in obsessive-compulsive disorder. The first is a loop connecting the orbitofrontal area, where sexual, violent and other primitive impulses normally arise, to the thalamic region, where the individual engages in more cognitive and perhaps behavioural responses as a result of this activation. A second loop connects the orbito-frontal region to the thalamic region, but via the corpus striatus. The striatal region is thought to control the degree of activity within the systems. It tends to fi lter out high levels of activity within the orbito-frontal area so that the thalamus does not over-respond to these initial impulses. In OCD, it may fail to correct over-activity in the orbito-frontal–thalamic loop, so the individual over-responds to environmental stimuli, and is unable to prevent their cognitive and behavioural responses to them. The f i rst system appears to be mediated by the excitatory neurotransmitter glutamic acid. The second system appears to be mediated by a number of neurotransmitters including serotonin, dopamine and GABA.

Psychoanalytic explanations

Freud (1922) considered OCD to result from the individual’s fear of their id impulses and their use of ego defence mechanisms to reduce this anxiety. This ‘battle’ between the two opposing forces is not played out in the unconscious. Instead, it involves explicit and dramatic thoughts and actions. The id impulses are typically evident through obsessive thoughts, while the compulsions are the result of ego defences. Two ego defence mechanisms are particularly common in obsessive-compulsive disorder: undoing and reaction formation. Undoing involves overt behaviours designed to counter the feared outcome: washing to avoid contamination, and so on. Reaction formation involves the adoption of behaviours diametrically opposed to the unacceptable impulses. The compulsively clean individual, for example, may experience strong ‘inappropriate’ sexual compulsions that are countered by their cleanliness and orderliness. The origins of OCD lie in diffi culties associated with the anal phase of development. Freud suggested that children in this stage gain gratifi cation through their bowel movements. If their parents prohibit or curb this pleasure through, for example, over-zealous potty training, this may result in a state of anger and aggressive id impulses expressed through soiling or other destructive behaviour. If the parents respond to this with further pressure, and if they embarrass the child in attempts to encourage toilet training, the child may feel shame and guilt as a consequence of their behaviour. So, the pleasure of the id begins to compete with the control of the ego. If this continues, the child may become fi xated in this stage and develop an obsessive personality. Traumas experienced in adulthood may result in a regression to this stage if the passage through it is incomplete. Not all psychodynamic theories are in agreement with Freud, although all agree that the disorder represents competition between aggressive impulses and attempts at controlling them.

Kleinian analysts suggest that as a consequence of stress some individuals may lose the ability to see both good and bad in the same object. Rather, they consider it to be either good or bad: there is a splitting of good and bad with no shades of feelings in between. Obsessive-compulsive disorders arise where the individual protects themselves against these ‘bad’ thoughts that would make them a ‘bad’ person through the use of obsessional behaviours.

Behavioural explanations

The behavioural model of obsessive-compulsive disorder is based on the two-process model of Mowrer (1947): fear of specifi c stimuli is acquired through classical conditioning and maintained by operant processes. What differentiates OCD from phobic or panic disorders is that anxiety arises in conditions from which the individual cannot easily escape. As a result, reductions of distress are achieved by engaging in covert or overt ritual or obsessive behaviours designed to reduce the anxiety associated with the particular stimulus. These form escape or avoidant behaviours, and reduce anxiety in the short term. However, they maintain longer-term anxiety and avoidant behaviour, as the affected individual fails to learn that no harm will occur in their absence. The individual also attempts to prevent initial contact with a feared stimulus.

Tags: causes, obsessive compulsive disorder, OCD