Keita Kawai: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
Kunihiro Iwamoto: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan. Electronic address: iwamoto@med.nagoya-u.ac.jp.
Seiko Miyata: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
Ippei Okada: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
Motoo Ando: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
Hiroshige Fujishiro: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
Akiko Noda: Department of Biomedical Sciences, Chubu University Graduate School of Life and Health Sciences, 1200, Matsumoto-cho, Kasugai-shi, Aichi, 487-8501, Kasugai, Japan.
Norio Ozaki: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
Masashi Ikeda: Department of Psychiatry, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Aichi, Showa-ku, Nagoya, 466-8550, Japan.
OBJECTIVE: One of the common symptoms of mood disorders is insomnia, and the recovery processes can be negatively impacted by a lack of restorative sleep. Although factors related to restorative sleep in healthy subjects have been investigated, evaluations of these factors in patients with depression have been rarely done. Patients with depression are known to have sleep-wake state discrepancy, which can further influence their restorative sleep beyond that associated with depressive symptoms. Thus, we investigated restorative sleep in depressed patients in our current study, and attempted to identify associated factors, with a particular focus on sleep-wake state discrepancy. METHODS: In the 91 participants evaluated in this cross-sectional study, all subjects filled out questionnaires on their symptoms prior to undergoing polysomnography (PSG). Sleep duration and restorative sleep were evaluated on the morning after the PSG. The association between restorative sleep and various factors was then examined using multiple regression analysis. RESULTS: A negative association with restorative sleep was found through multiple regression analysis for depressive symptoms (β = -0.055, p = 0.007), daytime sleepiness (β = -0.106, p = 0.020), and overestimation of wake after sleep onset (β = -0.006, p = 0.030). CONCLUSIONS: By subjectively and objectively assessing sleep, addressing depressive symptoms, and implementing appropriate sleep hygiene, clinicians could be able to improve restorative sleep in depressed patients.
