The essential features of conversion disorder are the nonintentionally produced symptoms or deficits affecting voluntary motor or sensory function that suggest but are not fully explained by a neurological or general medical condition, by the direct effects of a substance, or by a culturally sanctioned behavior or experience. Specific symptoms mentioned as examples in DSM-IV-TR include motor symptoms such as impaired coordination or balance, paralysis or localized weakness, difficulty swallowing or lump in throat (e.g., "globus hystericus"), aphonia, and urinary retention; sensory symptoms, including hallucinations, loss of touch or pain sensation, double vision, blindness, and deafness; and seizures or convulsions with voluntary motor or sensory components. Single episodes usually involve one symptom, but longitudinally, other conversion symptoms will be evident as well. Psychological factors generally appear to be involved, because symptoms often occur in the context of a conflictual situation that may in some way be resolved with the development of the symptom.