Mental tiredness in the Lundby study: incidence and course over 25 years

The Lundby study is a prospective, epidemiological survey of mental health in a total population. When evaluating the material of 2550 individuals followed from 1947 to 1972, we found a large group with mental tiredness as the dominating symptom. Next to depression this was the most frequent diagnosis in the population. According to our concept of Tiredness, one third of the women ran a lifetime risk of developing a first-ever episode of Tiredness, while the risk for men was one fifth. The incidence of Tiredness is described together with the total frequency of episodes. The course of mental illness starting with a first episode of Tiredness within the 25-year investigation period shows that about one third of the men and half of the women relapsed into Tiredness or other mental illnesses, not infrequently with a serious outcome. However, most of the episodes of Tiredness lasted less than 2 years and were of milder impairment. We emphasize the importance of further investigations by means of epidemiological, clinical and neurochemical methods as regards the heterogeneous syndrome of mental fatigue.