NEURASTHENIA IN A LONGITUDINAL COHORT STUDY OF YOUNG-ADULTS

This study examines the concept of neurasthenia in a longitudinal coho rt of young adults selected from a community sample of the canton of Z urich, Switzerland. The major focus is on the validity of the case def inition of neurasthenia. Close approximations of the proposed descript ive and research definitions of the TCD-10 are employed as well as the concept of 'irritable weakness' as described in 1831 by Kraus (1926-1 932). The prevalence of neurasthenia defined according to the ICD-10 c riteria was: 1% across 10 years and 0.9% in 1988 for a duration criter ion of greater than or equal to 3 months; and 8.1% across 10 years and 12% in 1988 for a duration criterion of greater than or equal to 1 mo nth. The duration criterion of greater than or equal to 3 months appea red to be excessively restrictive to represent individuals with neuras thenia in the community. Subjects with 1 month episodes of neurastheni a exhibited sufficient differences from controls and similarities to s ubjects with anxiety or depressive disorders to justify a 1 month dura tion criterion for neurasthenia in community samples. The clinical sig nificance of neurasthenia was indicated by the magnitude of subjective distress, and occupational and social impairment reported by the majo rity of the cases. Prospective assessment of the longitudinal course o f neurasthenia revealed that approximately 50% of the cases continued to exhibit this disorder at follow-up. Our findings suggest that neura sthenia is equally likely to represent an early manifestation of affec tive illness as it is a consequence in those neurasthenic subjects who exhibited comorbid affective disorders. The magnitude, chronicity, im pairment, longitudinal stability and distinction from anxiety and depr ession associated with this condition in the general population, sugge st that neurasthenia is an important diagnostic entity for which addit ional validation studies should be undertaken.