Obsessive-Compulsive Disorder (OCD)
Obsessive-compulsive disorder is defined as the presence of recurrent obsessions (persistent thoughts, impulses, or images) or compulsions (repetitive behaviour or thought patterns induced in an attempt to prevent anxiety) that are excessively time-consuming (taking more than an hour a day) or cause marked distress or significant impairment. The subject recognises that these patterns are excessive.
Differential diagnosis of obsessive-compulsive disorder includes generalised anxiety disorder, panic disorder, phobias, compulsive personality disorder, and hypochondriasis. While many of these syndromes are characterised by intrusive thoughts, few have associated rituals. The complex tics seen in some patients with Tourette’s syndrome may be difficult to distinguish from the compulsions seen in obsessive-compulsive disorder, and, in fact, there is significant overlap in symptoms between the two disorders (Rasmussen and Eisen, 1992).
Although the phenomenology of obsessive-compulsive disorder appears to be quite diverse, with many distinct kinds of obsessions and compulsions, there are three important core features: abnormal risk assessment, pathologic doubt, and incompleteness.
These features cut across phenomenological subtypes and may be useful in defining homogeneous subgroups with distinct treatment outcomes (Rasmussen and Eisen, 1992). Pigott (1998) also describes core features of OCD and subdivides them in two categories: altered risk appraisal versus need for completeness/symmetry.
For OCD, prevalence figures have been gradually growing over the years, as is the case for social phobia. Formerly OCD was thought to be quite rare, as people did not easily request treatment due to fear or shame (Rasmussen and Eisen, 1992). Recent epidemiological studies have shown a six-month prevalence rate of obsessive-compulsive disorder of approximately1% (Bebbington, 1998), to a lifetime prevalence rate of 2 - 3% (Hollander, 1997; Sasson et al., 1997), which means that OCD is much more common than previously suggested. Hollander (1997) calls OCD “the hidden epidemic”, where social phobia has been called “the neglected anxiety disorder” (Liebowitz, 1999). An earlier cross-national study by Weissman et al. (1994), using DSM-III criteria, reports annual prevalence rates ranging from 1.1/100 in Korea and New Zealand to 1.8/100 in Puerto Rico. The only exception was Taiwan (0.4/100), which has the lowest prevalence rates for all psychiatric disorders. Unfortunately, one of the best epidemiological studies in the USA, the NCS, did not address OCD because the diagnostic instrument used (the CIDI) excluded these cases (Bebbington, 1998).
Demographics and Risk Factors
The cross-national collaborative study examined OCD in seven different countries and found rather consistent figures. Age of onset was mid-to-late twenties. Female to male ratio ranged from 1.2 to 3.8 (Weissman et al., 1994), but earlier studies (among which was the ECA) report an equal sex distribution. In a study that specifically addressed gender differences in a clinical sample of OCDpatients, Castle et al. (1995) found a male to female ratio of 1: 1.35. Mean age of onset for men was 22 years, for women 26 years. Mean age at assessment did not differ significantly, 32.8 years for men and 34.6 years for women.
Obsessive-compulsive disorder has a chronic course, and few patients achieve true remission. Although symptoms may fluctuate over time, the disorder rarely is resolved spontaneously without appropriate treatment (Goodman, 1999). Full remission of OCD symptoms is rare, but episodic improvement in OCD symptoms is not uncommon (Pigott, 1998). In a 40-year follow-up of 122 OCD patients, Skoog and Skoog (1999) substantiated these generalities: 20% achieved complete recovery, 28% recovery with subclinical symptoms, another 35% still had clinical symptoms but did improve. Some 48% had had obsessive-compulsive disorder for more than 30 years.
Depression is the most frequent complication of OCD, as reported in several studies (Black and Noyes, 1990). Comorbidity rates in reported studies vary widely, from 19% to 90% (Milanfranchi et al., 1995). Within this wide range, however, most epidemiological studies show that about one-third of OCD patients suffer from a lifetime depressive episode. In clinical populations, comorbidity rates are increasing to about two-thirds (Crino and Andrews, 1996). Rasmussen found that one-third of OCD patients suffer from concurrent depression at referral, and two-thirds suffer from lifetime depression (Rasmussen and Eisen, 1994), a similar finding as in panic disorder. One explanation of the discrepancy between clinical and non-clinical studies could be that many OCD patients only seek help when depressed, as suggested by Black and Noyes (1990). As to chronology, it is found that most often the onset of OCD is before the depression (38%); transition from depression to OCD occurs in only 11% of case studies (Black and Noyes, 1990).
Personality disorders are frequently diagnosed in OCD, but may remit with effective anti-obsessional treatment (Pigott, 1998). This questions the validity of the axis II diagnosis at the outset. Also, a study by Ricciardi et al. (1992) showed that among 17 patients with OCD and concomitant personality disorder, after treatment nine out of ten responders no longer met the personality disorder criteria. OCD also co-exists with a number of other axis I disorders including panic disorder (54%, Crino and Andrews, 1996), social phobia (42%, Crino and Andrews, 1996), eating disorders (17%, Rasmussen and Eisen, 1994), and Tourette’s disorder (5%, Black and Noyes, 1990). Crino and Andrews (1996) remark that the high comorbidity of panic disorder and social phobia in OCD is in contrast to the low comorbidity of OCD in primary panic disorder or social phobic patients. However, they did not find any different rate of comorbid depression among the anxiety disorders.