The syndrome of functional memory disorder: definition, etiology, and natural course.

OBJECTIVES

Nonorganic, functional memory disorder (FMD) is frequent in memory clinic patients, and is an important differential diagnosis to prodromal dementia. The authors propose a definition of FMD as an acquired medical and psychological condition that is closely related to psychosocial burden and distress.

DESIGN

Prospective follow-up study, aimed to evaluate the natural course of FMD.

SETTING

University hospital memory clinic.

PARTICIPANTS

Seventy-three patients who suffered memory deficits and psychological distress and had normal test results. Forty-six attended a follow-up examination after a mean delay of 20.1 months.

MEASUREMENTS: FMD severity was assessed with a structured inventory and an overall self-rating scale. Objective performance was assessed by standardized tests of memory and attention.

RESULTS

Identified causes of distress were overwork, interpersonal conflicts, somatic illness, adjustment disorder, dysthymia, and Alzheimer phobia. At follow-up, FMD had resolved in only six patients, and persisted in 39. Average symptom severity showed only a minor reduction.

CONCLUSION

FMD is, in many instances, a long-term rather than transient problem. Possible reasons include the persistence of burden factors and the failure to evade the "stress spiral" of mutual reinforcement of distress and cognitive dysfunction.