Differential Diagnosis
The major diagnostic concern in evaluating potential conversion symptoms is the exclusion of occult neurological or other general medical conditions and substance (including medication)-induced etiologies. Appropriate evaluation of potential general medical conditions (e.g., multiple sclerosis, myasthenia gravis) should include careful review of the current presentation, the overall medical history, neurological and general physical examinations, and appropriate laboratory studies, including investigation for use of alcohol and other substances.
Pain Disorder or a Sexual Dysfunction is diagnosed instead of Conversion Disorder if the symptoms are limited to pain or to sexual dysfunction, respectively. An additional diagnosis of Conversion Disorder should not be made if conversion symptoms occur exclusively during the course of Somatization Disorder. Conversion Disorder is not diagnosed if symptoms are better accounted for by another mental disorder (e.g., catatonic symptoms or somatic delusions in Schizophrenia or other Psychotic Disorders or Mood Disorder or difficulty swallowing during a Panic Attack). In Hypochondriasis, the individual is preoccupied with the “serious disease” underlying the pseudoneurological symptoms, whereas in Conversion Disorder the focus is on the presenting symptom and there may be la belle indifference. In Body Dysmorphic Disorder, the emphasis is on a preoccupation with an imagined or slight defect in appearance, rather than a change in voluntary motor or sensory function. Conversion Disorder shares features with Dissociative Disorders. Both disorders involve symptoms that suggest neurological dysfunction and may also have shared antecedents. If both conversion and dissociative symptoms occur in the same individual (which is common), both diagnoses should be made.
It is controversial whether hallucinations ("pseudohallucinations") can be considered as the presenting symptom of Conversion Disorder. As distinguished from hallucinations that occur in the context of a Psychotic Disorder (e.g., Schizophrenia or another Psychotic Disorder, a Psychotic Disorder Due to a General Medical Condition, a Substance-Related Disorder, or a Mood Disorder With Psychotic Features), hallucinations in Conversion Disorder generally occur with intact insight in the absence of other psychotic symptoms, often involve more than one sensory modality (e.g., a hallucination involving visual, auditory, and tactile components), and often have a naive, fantastic, or childish content. They are often psychologically meaningful and tend to be described by the individual as an interesting story.
Symptoms of Factitious Disorders and Malingering are intentionally produced or feigned. In Factitious Disorder, the motivation is to assume the sick role and to obtain medical evaluation and treatment, whereas more obvious goals such as financial compensation, avoidance of duty, evasion of criminal prosecution, or obtaining drugs are apparent in Malingering. Such goals may resemble “secondary gain” in conversion symptoms, with the distinguishing feature of conversion symptoms being the lack of conscious intent in the production of the symptom.
