Clinical Vignette

A 36-year-old high school teacher consulted a psychiatrist because of difficulty driving to work. He had a long-standing fear that he would lose control of his car and accidentally run down a pedestrian. Recently, this fear had intensified to the extent that he had to stop driving and examine his car’s bumpers for signs of blood whenever he hit a bump in the road. It was taking him more than 2 hours each morning to make a 20-minute commute. On further questioning, the patient also admitted to fear that a knife or fork would accidentally slip from his hand while he ate dinner, and that he would inadvertently stab someone. He also had to check the appliances and faucets four times before leaving home to ensure they had been turned off, and he had a 1-hour ritual of washing and shaving that he needed to perform in strict order every morning.

Much to the patient’s dismay, the psychiatrist felt compelled to warn both his family and the police that the patient’s “suppressed anger” might get out of control. His family, however, was well aware of the patient’s habits and fears, and declared that they were not frightened. Likewise, the police dismissed the case after finding no criminal history and no imminent threat.

Despite his time-wasting habits and rituals, the patient had a successful career. He was well liked by friends and family, who worked around his “eccentricities.” His symptoms gradually diminished with combined treatment (provided by a second psychiatrist) with a serotonergic antidepressant and a behavioral program of exposure and response prevention.

Clinical Presentation

OCD patients usually fit into one of a few categories. Some clean obsessively and worry about germs or contamination (Fig. 22-1). Others repeatedly check that they’ve turned off their appliances or locked their doors. Some are obsessed with symmetry or arranging their possessions in exactly the right order. Another group hoards what most would call “junk.” Often, OCD patients are troubled by thoughts of violence; they may fear that they will run someone over while driving or that as they eat a knife will slip from their hands and cut someone. Inexperienced clinicians sometimes err by seeing these obsessions as real threats, thereby exacerbating patients’ fears. In fact, OCD patients are terrified of these thoughts and do not act on them.

Figure 22-1 Obsessive-Compulsive Disorder.

Recently, factor analysis has suggested that hoarding patients are a distinct subtype, and possibly even a separate disorder. They have a different pattern of neuropsychological impairment, and they respond less well to medication.

Most diagnostic classifications employ a category of Obsessive-Compulsive Personality Disorder, or something similar, to describe individuals who are highly controlled, formal, emotionally distant, parsimonious, perfectionistic, resistant to change, and intolerant of ambiguity. Despite the similarity in names, this personality constellation and OCD are unrelated.

Several other disorders of impulse control seem superficially related to OCD. Pathologic gamblers and “sex addicts” seem obsessed and compulsive, as do sufferers from trichotillomania, the compulsion to pull out body hairs. However, these apparently similar patients share neither the unique pathophysiology of OCD described below nor the same pattern of response to treatment.

Patients with OCD typically have either no structural brain abnormalities or subtle loss of frontal tissue. In contrast, functional brain imaging (positron emission tomography or functional magnetic resonance) reliably shows excess metabolic activity in caudate and frontal regions; although OCD is a clinical syndrome, it can, in principle, be detected by brain scan! (This pattern is not required to diagnose OCD but the association is robust.) They typically exhibit minor difficulties on tests of executive function and less frequently disorders of short-term memory.

Treatment

OCD patients share a unique pattern of response to medications. They improve when given serotonin reuptake inhibitor antidepressants. However, at the clinical level, OCD does not respond as well to serotonergic antidepressants as does depression per se. Typically, higher doses of medication are required to treat OCD, the response is slower, and full remissions with medication alone are uncommon. In contrast, the antidepressants that block reuptake of norepinephrine, and that are as effective for treating depression as the serotonergic antidepressants, are ineffective for OCD. Curiously, a canine model for OCD, the Acral Paw Lick Syndrome, shows the same pattern of medication response. For patients with only a partial response, the addition of a low-dose neuroleptic medication is often helpful. Patients who are refractory to all other treatments and severely impaired by their illness are candidates for Deep Brain Stimulation or other neurosurgical interventions.

Some form of behavioral therapy is almost always also required. The most effective of these is exposure and response prevention. If a patient has a compulsion to wash his hands, the quickest way to cure him is to get dirt on his hands and prevent him from washing them. Naturally, patients need support and encouragement to try this method. When patients improve, their functional imaging abnormalities resolve. This response is independent of whether their primary treatment modality was a specific medication or primary behavioral therapy.

Some cases of childhood-onset OCD, especially those with abrupt onset or associated movement disorders, are caused by Streptococcal infections. There is subsequent reactivity of anti-streptococcal antibodies within the basal ganglia. A combination of antibiotic treatment and plasmapheresis, to remove the antibodies, are helpful to these children.