A shared universe › Blog › When autumn comes and your mood drops · Español
In the early hours of the last Sunday of October the clocks went back an hour, and since then it has been dark by mid-afternoon. Some people barely notice, and others feel that when the light goes, their mood goes with it. There is an explanation, and there are things that help.
The body has an internal clock that is reset every day by light. When the days shorten, that setting changes, and with it the brain chemicals linked to sleep and mood, such as melatonin and serotonin, as the UK’s National Health Service (NHS) explains. And the days keep getting shorter until the December solstice.
A postal survey of 1,671 people in four cities in the United States revealed very recognisable winter patterns: more sleep, more weight and a lower mood. For some people it is a bearable nuisance; for others, a good deal more.
The story of how it was discovered begins with a patient. Herb Kern, a research engineer, had spent years noting down how his mood changed and saw that he became depressed every winter. He suspected that the lack of light had something to do with it and told the scientists at the US National Institute of Mental Health who were studying the body’s rhythms. They treated him with intense artificial light and he improved. The case was published in 1982.
One of those researchers was the psychiatrist Norman Rosenthal, born in South Africa, who had noticed that he himself dimmed in the New York winters. In 1984 he and his team described 29 patients who became depressed every year at the same time, slept too much, ate more and craved carbohydrates. He gave it a name: seasonal affective disorder. In early trials with 11 of them, lengthening the day with intense artificial light improved their mood.
There is a long way between noticing that the days are shortening and having a disorder. The NHS describes seasonal affective disorder as a type of depression that usually appears in winter, with low mood, loss of interest in what you used to enjoy, tiredness and a bigger appetite. To speak of a seasonal pattern, the American Psychiatric Association’s diagnostic manual requires it to recur at the same time of year for at least two years running. Researchers also describe a milder form, which you notice but which lets you carry on with life.
The idea has its critics. The first studies found more cases the further north people lived, but in 2016 a study based on a large survey of adults in the United States found no link between depression and latitude, season or hours of sunshine, and its authors proposed reviewing the diagnosis. The seasonal pattern is still recognised in the manual, and the debate goes on. What is increasingly recognised is that getting enough light matters for the wellbeing of body and mind.
A team from the universities of Copenhagen and Aarhus analysed more than a hundred and eighty-five thousand hospital contacts for depression in Denmark between 1995 and 2012. After the switch from summer time to winter time, new hospital diagnoses of depression rose by 11%, and the rise took about ten weeks to fade. The spring change did not have that effect.
The authors believe that part of it is the shock of seeing night fall suddenly an hour earlier, as a warning of a long season of short days. It is an observational study and it concerns cases seen in hospital, but it shows that this Sunday in October is not a matter of indifference to everyone.
In 1996 the researcher Anna Wirz-Justice, of the University of Basel, tried something very simple with people who had seasonal affective disorder: an hour’s walk outdoors every morning for a week. Half of them recovered, compared with one in four in the group that received weak artificial light. It is a single study and it lasted a week, but it is in line with what is known about light.
The difference between indoors and outdoors is enormous. Outside, a cloudy day gives around a thousand lux; the living room of a home with the lamp on comes to about 50, and an office between 320 and 500. That is why going out, even when it is grey, is not the same as sitting beside the lamp.
There are also very bright lamps, of around ten thousand lux, which are used as a treatment. If you are considering one, talk to your doctor first, who can tell you whether it is right for you and how to use it.
If your low mood lasts more than two weeks, almost every day; if you stop enjoying what you used to like; if you struggle to keep up with work or the house; or if the same thing happens every autumn for years, talk to your GP. It can be treated. And if thoughts of death appear, don’t keep them to yourself. In Spain you can talk to a person at the Teléfono de la Esperanza, 717 003 717, at any time. If you are thinking of ending your life, call 024: it is free and answered 24 hours a day. If you are in another country, call your local emergency number or a helpline there.
When it gets dark at six, the sky in A shared universe stays lit. If these weeks feel like an uphill struggle, say so on a star with “What weighs on me”, without your name. Seven days of light, and someone stopping by to leave you a touch.