The Effects of Time Transitions on Depression

Medical Reviewer

Unusually for the United Kingdom, we’ve been enjoying an early summer. By the end of May I even had a decent tan. All that stopped 24 hours ago. Crystal blue skies and puffy white clouds gave way to somber gray and constant rain. My mood isn’t quite as chipper it was.

You may have heard the German proverb, "There’s no such thing as bad weather, only inappropriate clothing.” That’s fine up to a point, but it ignores that fact that weather, especially when connected to diminishing levels of daylight, has different effects on people. Danish poet Henrik Norbrandt writes there are 16 months in the year, including, "October, November, November, November, November.” No prizes for guessing his views about shortened days!

Time Transitions

Did you know that depression diagnoses in Denmark increase immediately after the transition from daylight saving to standard time? This is the claim of Danish Professor Søren D. Østergaard from Aarhus University Hospital in Risskov. The study, a collaboration between the universities of Aarhus, Copenhagen and Stanford, is published in the October 2016 edition of Epidemiology and is summarised on The results reveal that changing the clock so that an hour of daylight is lost in the afternoon results in an eight percent increase in depression diagnoses.

Time transitions occur twice a year in the UK. I’m very familiar with the prospect of getting up and returning home in the dark, the part in between being illuminated by artificial lights. Days like this can feel very long and as far as health is concerned there may be other implications. For example, daylight saving time has been linked to stroke risk, an increase in cluster headaches, male suicide rates and cancer.

Time Zones

These days we can hop on a plane and find ourselves in a country whose time zone is radically different to the one we left. At one level we accept that a touch of jet lag is the price we pay for long distance travel, but have you ever wondered about how your body and brain reacts?

Jet lag happens because long haul flights desynchronize our circadian rhythm. Our bodies are attuned to a 24-hour cycle in which hormones and neurotransmitters regulate everything from sleep, to digestion, blood pressure and our state of mind. Disrupt the circadian rhythm and all these processes are affected.

Switching time zones regularly can have some fairly dramatic effects. One study on 62 experienced female cabin crew staff, reported in Australian Science, found increased secretions of the stress hormone cortisol, and impaired thinking. Even after years of experience, it appears the body is unable to adapt to the effects of jet lag.

Treatment Options

As days get shorter our body clock gradually makes the adjustment, but in those affected by body clock disruptions their vulnerability can lead to depression. The use of light therapy is well documented, but the practicality of using it daily for 30 minutes or longer for up to five months at a time is quite burdensome.

When psychologists from the University of Vermont compared light therapy with cognitive-behavioral therapy over two winters, they found 46 per cent of volunteers using light therapy reported symptoms of depression during the second winter. Only 27 per cent of those in the cognitive therapy group reported similar symptoms. Of particular note is the fact that those using light therapy reported more severe symptoms than those who used cognitive therapy.

Based on these figures, cognitive therapy would appear to be the superior treatment choice. Light therapy seems effective, but not only were relapse rates and severity of relapse symptoms lower in those using psychological therapies, but the time taken for therapy only involved two 50-minute group sessions per week.

See more helpful articles:

Can the ‘Body Clock’ Help Cure Sleep Disorders?

Light Therapy for ‘Indoor’ Seasonal Affective Disorder

Supportive Counseling and Supportive Therapy for Depression