Sleep and Mental Health


This is an online blog from one of our staff who is now in London

The other day in London,, the heat exceeded 40 degrees Celsius. Few homes in the UK have air conditioning. On the contrary, houses are built to keep the heat inside. The high indoor temperature continued even at night. I had a hard time sleeping through the night, so I could not get tired and felt a little sick.

In this blog, I will talk about sleep based on psychological research.

The Importance of Sleep

We have to take in an overwhelming amount of information throughout the day. If we were to memorize all that information, it is easy to imagine that we would be overwhelmed by the volume of data.

Fortunately, we forget most information deemed unimportant. On the other hand, important information is replayed subconsciously during sleep and is then committed to long-term memory. [1]

Exposure to stress during our waking hours leads to the release of hormones that act to weaken our immune system. Sleep lowers the body’s stress levels, allowing the immune system to function optimally. [2]

Thus, when sleep is disturbed, physical and psychological health is affected.

Sleep’s Relationship to our Psychological State

It has been suggested that poor sleep quality is linked to the risk of developing depression over the long term. One of the most prominent symptoms of depression is sleep disturbance, but insomnia may also be solely responsible for the development of depression. [3] It has been reported that many people with anxiety or panic disorders have experienced sleep disturbances before. [4] Therefore, improving sleep quality may be an effective way to reduce the risk and symptoms of depression, anxiety, and panic disorders.

Ways to Improve Sleep Hygiene [5].

Sleep hygiene refers to the behaviors and environment that contribute to good sleep. Here are some tips for getting a good night’s sleep.

– Exercise regularly.
– Engage in means to take your focus off things that stress you out, such as engaging in aromatherapy or mindfulness [6,7].
– Try wearing earplugs, especially if you are sensitive to sound, as brain activity responds to sound, even unconsciously [8].
– Keep a regular sleep schedule.

In addition to the above recommendations, insomniacs should seek the advice of a psychologist trained in treatments for insomnia (such as CBT-I) or a psychiatrist who can prescribe medications that are right for you.


It will get hotter and hotter in Japan, and there will be more and more nights when it is difficult to sleep. In addition to the above methods, pay attention to the appropriate room temperature and focus on getting as much good sleep as possible.


[1] Klinzing, J. G., Niethard, N., & Born, J. (2019). Mechanisms of systems memory consolidation during sleep Nature Neuroscience, 22(10), 1598-1610. Available from:

[2] Jawabri, K. L., & Raja, A. (2022, May 8). Physiology, Sleep Patterns. Florida. Retrieved from

[3] Buysse, D. J., Angst, J., Gamma, A., Ajdacic, V., Eich, D., & Rössler, W. (2008). Prevalence, course, and comorbidity of insomnia and depression in young adults. sleep, 31(4), 473-480. Available at:

[4] Batterham, P. J., Glozier, N., & Christensen, H. (2012). Sleep disturbance, personality and the onset of depression and anxiety: a prospective cohort study. Australian & New Zealand Journal of Psychiatry, 46(11), 1089-1098.

[5] Irish, L. A., Kline, C. E., Gunn, H. E., Buysse, D. J., & Hall, M. H. (2015). The role of sleep hygiene in promoting Public Health: A review of empirical evidence. Sleep Medicine Reviews, 22, 23-36. Available at:

[6] Hwang, E., & Shin, S. (2015). The effects of aromatherapy on sleep improvement: A Systematic Literature Review and meta-analysis. The Journal of Alternative and Complementary Medicine, 21(2), 61-68.

[7] Ong, J. C., Shapiro, S. L., & Manber, R. (2008). Combining mindfulness meditation with cognitive-behavior therapy for insomnia: A treatment-development study. Behavior Therapy, 39(2), 171-182.

[8] Wilkinson, R. T., & Campbell, K. B. (1984). Effects of traffic noise on quality of sleep: Assessment by EEG, subjective report, or performance the next day. America, 75(2), 468-475.