OCD

Related Spectrum Disorders

It is now hypothesised that OCD is closely related to a variety of other spectrum or related disorders (Hollander, 1997). Up to 10% of the U.S. population may suffer from an OCD spectrum disorder, compared with 2% to 3% with OCD. Spectrum disorders all involve some degree of compulsive or impulsive behaviour and consist of any of three specific core symptoms:

• pre-occupation or obsession with specific bodily sensations or appearance (e.g., body dysmorphic disorder, depersonalisation, eating disorders, hypochondriasis);
• selected neurologic disorders (e.g., Tourette’s syndrome, Sydenham’s chorea, torticollis, autism) often involving basal ganglia dysfunction presenting with repetitive behaviours;
• and impulsivity or certain types of impulse control disorder (e.g., sexual compulsions, trichotillomania, pathological gambling, kleptomania, and self-injurious behaviour).

Spectrum disorders share other characteristics with OCD including features such as age at onset, clinical course, family history, and response to SSRIs and behavioural therapy. Such behaviours can be placed on a risk-aversive/impulsive spectrum. At the compulsive end of the scale are an exaggerated sense of harm and a heightened sense of risk while at the impulsive end is an underestimation of harm and risk, causing behaviour that is dangerous or otherwise troublesome.

Both compulsivity and impulsivity involve difficulty in delaying or inhibiting repetitive behaviours, although the mechanisms of action differ. Compulsive behaviours are an attempt to reduce anxiety and discomfort, while impulsive actions are an attempt to obtain pleasure, arousal, or gratification.

Both genders demonstrate impulsive behaviour; men may gamble, intermittently explode with anger, set fires and act out sexual behaviour and women are more likely to steal, pull out their hair, injure themselves, shop compulsively and binge eat. It is not clear whether such gender differences are hormonal, cultural., or a combination of both (Hollander, 1997).

It seems that the SSRIs can successfully treat the OCD-related disorders. We will now discuss the role of citalopram in these disorders.

Trichotillomania (repetitive hair pulling) lies at the impulsive end of the OCD scale.
Although classified as a disorder of impulse control, trichotillomania (repetitive hair pulling) may have some phenomenological overlap with the impulsive end of obsessive-compulsive disorder (OCD). The question arises as to whether trichotillomania is best conceptualised as a disorder characterised by impulsivity or compulsivity. Impulsive and compulsive symptoms were compared in 43 patients who presented for treatment of trichotillomania, OCD or impulsive personality disorder. Trichotillomania patients had significantly lower scores of obsessive-compulsive symptoms than OCD patients, and significantly higher impulsiveness scores than this group (Stein et al., 1995c). Despite this overlap trichotillomania lacks preceding obsessions (Stein et al., 1995a) and is mostly present in females.

SSRIs may have a role in the treatment of trichotillomania but additional research is needed. The use of SSRIs as an augmentation strategy with agents working on other neurotransmitters , such as dopamine, has been described (Stein and Hollander, 1992).

Symptoms such as pica (eating non-nutritious substances) can, arguably, fall into the category of OCD-spectrum disorders as well. This hypothesis has been tested and in a report of five cases of pica, two patients were found to have pica as a compulsion and two more were reminiscent of an impulse control disorder. Four of the five patients responded to treatment with an SSRI. The conclusion is that at least some cases of pica may lie in this OCD-spectrum (Stein et al., 1996a).

Olfactory reference syndrome, a disorder characterised by persistent preoccupation with body odour, accompanied by shame and embarrassment, may also be an OCD spectrum disorder. Two cases of olfactory reference syndrome, with accompanying phenomenological and neurobiological data, have been reported. A number of phenomenological and neurobiological features in these patients were at least partially reminiscent of OCD. In particular, both patients demonstrated significant improvement upon treatment with a serotonin reuptake inhibitor (Stein et al., 1998a).