Table 3 shows that sleep efficiency ≤85% was more frequently recorded using subjective measures than objective measures. In Table 4,
patients with more severe depression revealed that larger differences
were found between subjective and objective sleep data. Because depression causes sleep disorders, the medicine depressed patients used
may have caused them to experience less REM and believe that their
total sleep time was shorter and that their sleep efficiency was poor. A
previous study on sleep patterns indicated that most depressed patients
complained of lower sleep efficiency and indicated that sleep efficiency
differed between people with depression and those without depression
(Gupta et al., 2009). Thus, the subjective and objective data of depression patients possibly differ significantly. Table 3 shows that the number
of patients with a TST of 6.5 hours or less was 4 in objective data, possibly because the lights at the hospital in which the patients were staying
were turned off at 10:00 p.m. and turned on at 6:00 a.m. This schedule
may have caused patients to follow the habitual sleep or wake schedule
in the ward.