Demographics
Gender distribution of the sample differed significantly, with a marked predominance of female participants with TTM compared to almost equal numbers of male and female participants with OCD. TTM patients had an earlier age of onset of illness compared to patients with OCD (Table 2).
Clinical features
Comorbidity
A number of disorders were more frequent in females with OCD: major depressive disorder (MDD), dysthymia, panic disorder, hypochondriasis and intermittent explosive disorder. In terms of the selected Axis II disorders, obsessive-compulsive personality disorder (OCPD) was more frequent in females with OCD (Table 3).
Symptom severity
The severity of OC symptoms in OCD patients, as measured by the YBOCS severity scale, was 20.1 (± 8.0). TTM patients scored 16.1 (± 6.5) on average on the MGHHPS. Compared to TTM patients, females with OCD had significantly higher depressive symptom scores on the BDI (Table 2).
Disability
The DP was administered to a total of 95 OCD and 30 TTM patients (Table 4). OCD patients reported significantly more lifetime impairment due to their illness than TTM patients. More specifically, OCD patients were more impaired in terms of work-related functioning, family functioning, marriage / dating, activities of daily life, and other activities (which included religious activities, membership of clubs, having hobbies, participation in sports etc.) and had more suicidality. One-way ANOVA's showed that the primary diagnosis (either OCD or TTM) (F = 11.84; p = 0.001) and panic disorder (F = 6.73; p = 0.01) had a significant effect on the levels of disability. However, there was no significant interaction effect between the primary diagnosis and panic disorder, suggesting that the levels of disability were dependent on primary diagnosis (either OCD or TTM) (F = 5.79; p = 0.02) and not influenced by the absence or presence of panic disorder (F = 0.001; p = 0.98).
Character / Temperament
Compared to OCD patients, patients with TTM scored significantly higher on novelty seeking, whereas OCD patients had significantly greater harm avoidance (Table 5).
Schemas
Fifty-nine OCD and 26 TTM patients fully completed the YSQ. Pair-wise comparison tests (Mann-Whitney U) indicated that OCD and TTM patients differed significantly on 5 schemas, i.e. mistrust / abuse, social isolation, shame / defectiveness, subjugation and emotional inhibition (Table 7). More specifically, OCD patients had significantly higher scores on each of these schemas compared to TTM patients.
Precipitating factors
Interpersonal trauma history
OCD patients reported more childhood sexual abuse than did TTM patients (p = .04).
Brain trauma history
OCD and TTM patients did not differ significantly in terms of a history of serious head injury associated with the onset of OCD or TTM.
History of autoimmune infections
Compared to none in the TTM group, 9 OCD patients reported onset of their OCD with an episode of bacterial pharyngitis (p = .06). In terms of other autoimmune infections, OCD and TTM patients did not differ significantly.
Hormonal influence
Female OCD and TTM patients did not differ significantly in terms of the impact of premenstrual/menstrual/menopausal symptoms on their illness. Compared to 42 (38.5%) of 109 OCD patients who reported OC symptom changes in the premenstrual/menstrual period, 16 of 32 TTM patients (50%) reported regular changes in their symptoms during this time. Seventeen (n = 17) OCD patients were menopausal and 35.3% (n = 6) of these women reported that their OC symptoms only started with menopause. One of the TTM patients had gone through menopause with no effect on her hair-pulling symptoms. However, OCD and TTM patients differed significantly in terms of the temporal association between pregnancy/puerperium and onset of illness: 42.6% (26 of 61) OCD patients reported OCD onset while pregnant or within a month of childbirth, compared to 7.7% (1 of 13) of TTM patients (χ2 = 6.8; p = .009).
Treatment response
Significantly fewer TTM patients reported a clinical response to either CBT- or SRI-treatment than did OCD patients (Table 2).
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