Specific Culture, Age, and Gender Features
Conversion Disorder has been reported to be more common in rural populations, individuals of lower socioeconomic status, and individuals less knowledgeable about medical and psychological concepts. Higher rates of conversion symptoms are reported in developing regions, with the incidence generally declining with increasing development. Falling down with loss or alteration of consciousness is a feature of a variety of culture-specific syndromes. The form of conversion symptoms reflects local cultural ideas about acceptable and credible ways to express distress. Changes resembling conversion symptoms (as well as dissociative symptoms) are common aspects of certain culturally sanctioned religious and healing rituals. The clinician must assess whether such symptoms are fully explained in the particular social context, and whether they result in clinically significant distress, disability, or role impairment.
Conversion symptoms in children under age 10 years are usually limited to gait problems or seizures. Conversion Disorder appears to be more frequent in women than in men, with reported ratios varying from 2:1 to 10:1. Especially in women, symptoms are much more common on the left than on the right side of the body. Women (rarely men) presenting with conversion symptoms may later manifest the full picture of Somatization Disorder. In men, there is an association between Conversion Disorder and Antisocial Personality Disorder. In addition, Conversion Disorder in men is often seen in the context of industrial accidents or the military.
Prevalence
Reported rates of Conversion Disorder have varied widely, ranging from 11/100,000 to 500/100,000 in general population samples. It has been reported in up to 3% of outpatient referrals to mental health clinics. Studies of general medical/surgical inpatients have identified conversion symptom rates ranging between 1% and 14%.
Course
The onset of Conversion Disorder is generally from late childhood to early adulthood, rarely before age 10 years or after age 35 years, but onset as late as the ninth decade of life has been reported. When an apparent Conversion Disorder first develops in middle or old age, the probability of an occult neurological or other general medical condition is high. The onset of Conversion Disorder is generally acute, but gradually increasing symptomatology may also occur. Typically, individual conversion symptoms are of short duration. In individuals hospitalized with conversion symptoms, symptoms will remit within 2 weeks in most cases. Recurrence is common, occurring in from one-fifth to one-quarter of individuals within 1 year, with a single recurrence predicting future episodes. Factors that are associated with good prognosis include acute onset, presence of clearly identifiable stress at the time of onset, a short interval between onset and the institution of treatment, and above-average intelligence. Symptoms of paralysis, aphonia, and blindness are associated with a good prognosis, whereas tremor and seizures are not.
Familial Pattern
Limited data suggest that conversion symptoms are more frequent in relatives of individuals with Conversion Disorder. Increased risk of Conversion Disorder in monozygotic twin pairs but not in dizygotic twin pairs has been reported.