Pp. Chang et al., INSOMNIA IN YOUNG MEN AND SUBSEQUENT DEPRESSION - THE HOPKINS,JOHNS PRECURSORS STUDY, American journal of epidemiology, 146(2), 1997, pp. 105-114
The Johns Hopkins Precursors Study, a long-term prospective study, was
used to study the relation between self-reported sleep disturbances a
nd subsequent clinical depression and psychiatric distress. A total of
1,053 men provided information on sleep habits during medical school
at The Johns Hopkins University (classes of 1948-1964) and have been f
ollowed since graduation. During a median follow-up period of 34 years
(range 1-45), 101 men developed clinical depression (cumulative incid
ence at 40 years, 12.2%), including 13 suicides. In Cox proportional h
azards analysis adjusted for age at graduation, class year, parental h
istory of clinical depression, coffee drinking, and measures of temper
ament, the relative risk of clinical depression was greater in those w
ho reported insomnia in medical school (relative risk (RR) 2.0, 95% co
nfidence interval (CI) 1.2-3.3) compared with those who did not and gr
eater in those with difficulty sleeping under stress in medical school
(RR 1.8, 95% CI 1.2-2.7) compared with those who did not report diffi
culty. There were weaker associations for those who reported poor qual
ity of steep (RR 1.6, 95% CI 0.9-2.9) and sleep duration of 7 hours or
less (RR 1.5, 95% CI 0.9-2.3) with development of clinical depression
. Similar associations were observed between reports of sleep disturba
nces in medical school and psychiatric distress assessed in 1988 by th
e General Health Questionnaire. These findings suggest that insomnia i
n young men is indicative of a greater risk for subsequent clinical de
pression and psychiatric distress that persists for at least 30 years.