W. Yamadera et al., CLINICAL-FEATURES OF CIRCADIAN-RHYTHM SLEEP DISORDERS IN OUTPATIENTS, PSYCHIATRY AND CLINICAL NEUROSCIENCES, 52(3), 1998, pp. 311-316
The clinical data of 86 cases of primary circadian rhythm sleep disord
er (primary CRSD) were retrospectively examined and compared to 40 cas
es of secondary circadian rhythm sleep disorder (secondary CRSD), who
had presented with some kind of psychiatric or medical disorder, and h
ad exhibited sleep-wake rhythm disorders that were judged to be second
ary CRSD based on sleep logs. The comparison of cases found that: (i)
the mean age at first presentation to the clinic was significantly you
nger for primary CRSD compared to secondary CRSD; (ii) more secondary
CRSD cases were unemployed than were Primary CRSD cases; (iii) more ca
ses in the secondary CRSD group had a clear trigger for sleep-wake rhy
thm disorder onset than cases in die primary CRSD group; and (iv) the
types of sleep-wake rhythm disorders in the primary CRSD group consist
ed of delayed sleep phase syndrome (DSPS), 72 (83.7%), non-24 pattern,
11 (12.8%), and irregular, 3 (3.5%), In the secondary CRSD group ther
e were 25 (62.5%) cases of DSPS pattern, 1 (2.5%) of non-24 pattern an
d 14 (35.0%) with irregular pattern. The 56 (65.1%) cases with primary
CRSD showed good response to vitamin B12 and bright light therapy, ho
wever, 28 (70.0%) cases with secondary CRSD did not respond to such th
erapies.