It is a commonly held belief that summer is associated with better mood than winter and that people are more likely to be happy on sunny days. I’ve noticed it in my practice where there seems to be a yearly surge in referrals over the winter months, and like most people I’ve attributed it partly to the ‘depressing weather’. But is this assumption justified?
IS THERE A WEATHER/MOOD LINK?
The largest test of the weather/mood hypothesis was a study by David Watson, reported in his book Mood and Temperament (2000). In the study 478 undergraduate students in Dallas, Texas, had to collect daily mood reports during autumn or spring. They collected 20,818 observations. Surprisingly, no significant correlations were found between mood and any of the weather variables that were assessed including sunshine, air pressure/weight, temperature, or rain.
Watson also investigated the effect of extreme weather conditions on mood comparing days that had zero per cent sunshine with days that had 100 per cent sunshine. He found that participants reported higher intensity of both positive and negative moods (that is, more extreme scores) on days with more sunshine.
These findings seem hard to believe given the widely held belief that good weather is synonymous with good mood.
WHAT DO OTHER STUDIES SHOW?
In ‘A Warm Heart and a Clear Head’, a 2005 study by Matthew C. Keller et al in the journal Psychological Science, it was found that “pleasant weather (higher temperature or barometric pressure) was related to higher mood, better memory, and ‘broadened’ cognitive style during spring, as time spent outside increased”.
The authors surmised it was because people had been deprived of good weather during winter that they found this relationship in spring, but not at other times in the year. In fact, they found that in summer, time spent outside on days with higher temperatures was related to decreased mood. The authors note the study’s message is clear: “If you wish to reap the psychological benefits of good springtime weather, go outside.”
A German study reported in the journal Emotion in 2008 looked at a broader range of weather parameters to study the effects of daily weather changes on mood.
Specifically, they studied the effect of temperature, wind power, sunlight, rain, air pressure and photoperiod (daily exposure to light). Their results mirrored the previous two studies in showing no significant effects of daily weather on positive mood.
WHY DO WE BELIEVE WEATHER AND MOOD ARE RELATED?
The authors of the 2008 study suggest there are two possible factors that may account for our continuing beliefs in the link between mood and weather despite the lack of evidence.
One is related to history; people used to be far more dependent on weather-related phenomena for their shelter and food. While there are obviously people who are still in this position (for example, farmers), they are a smaller sector of overall society now.
The second possible factor may be that we are now aware of the condition called Seasonal Affective Disorder (SAD; the changing of mood with the seasons) and may even know or have come across somebody who suffers from it.
This awareness makes us conscious of the relationship between day-to-day weather and its possible effect on our mood as opposed to seasonal effects.
SAD: SEASONAL AFFECTIVE DISORDER
Unlike the few studies researching the impact of daily weather variation on mood, the effects of seasons on mood have been given much more attention. Although most of us will notice some seasonal changes in our activity levels and perhaps our mood, some people experience marked changes in mood according to the season. These people may have SAD.
WHAT IS IT?
SAD is a form of clinical depression. The possible symptoms that are present in SAD and non-seasonal depression are the same but SAD tends to recur every year and follows a seasonal pattern of onset during the winter months and remission in spring. This contrasts with plain old non-seasonal depression which can occur at any time, and is often in response to stressful or upsetting life events.
Criteria for a diagnosis of SAD are:
– You experience your mood changing (usually becoming more depressed) with a particular time of the year.
– In the past two years, you have experienced two depressive episodes that coincide with a particular time of the year (usually winter).
– Full remissions (no symptoms) also occur at a particular time of the year (for example depression disappears in spring).
– There is no obvious social/psychological reason to account for season-related depression/stress.
SAD is most commonly linked to autumn and winter, however there are some cases where people become depressed in spring and summer.
Most people experience changes in physical functions including:
– Sleeping (despite getting more sleep, you don’t feel refreshed on waking).
– Eating (research on people with SAD shows that they get energy from high-carbohydrate foods which is the opposite of people without SAD. Non-depressed people tend to feel more drowsy if they eat carbohydrates).
– Weight gain.
– Considerably lowered energy levels.
– Lower sex drive.
– Difficulty concentrating.
WHO DOES IT AFFECT?
SAD is four times as common in women than men, is most common in people between their 20s and 40s and declines with age. SAD characterises 10-20 per cent of recurrent depression cases. Research suggests that a long-term course of SAD is variable; 28-44 per cent of SAD patients later develop depression that is not seasonal, 14-38 per cent go into remission, while 22-42 per cent continue to have pure SAD (onset at winter and remission in spring). Historically, Winston Churchill, Abraham Lincoln, and Gustav Mahler are all said to have possibly suffered SAD.
People differ in their tendency to change mood and behaviour according to the season, and it has been suggested that SAD is the extreme case of a continuum of normal human variation. It is also generally thought that SAD prevalence increases with geographic latitude, although other studies have demonstrated that increase in latitude does not equate with increased SAD rates.
Studies focusing on genetic factors as possible contributors to SAD have suggested that it does run in families. In summarising these studies, Dr L. Sher (2001) states that among the people who have SAD, between 13 per cent and 17 per cent of their first-degree relatives are also affected. This is significantly higher than the average rates of SAD in the general population.
WHAT ARE THE CAUSES?
There are a number of theories that seek to explain what the probable causes of SAD are:
1. Some say reduced sunlight disrupts the circadian rhythms that regulate the body clock, telling us when it’s time to sleep and wake up.
2. Others say SAD is related to melatonin which is a sleep-related hormone. The production of melatonin actually increases during the long nights of winter.
3. Others point to serotonin, a neurotransmitter, as when people are depressed they often have lower levels of serotonin.
Kelly Rohan, a psychologist based at the University of Vermont, has proposed that both physiological and psychological factors contribute to SAD. The physiological component is brought about by the environment (such as impacting circadian rhythms, hormones or neurotransmitters). This then interacts with psychological vulnerability, which includes thoughts typical of non-seasonal depression (for example, ‘I’m worthless and the future looks bleak’). Thoughts about the environment, specifically light availability (‘There is less light; we’re counting down to the shortest day’), cues that the seasons are changing (‘The leaves on the trees are changing colour, soon it will be winter’) and weather also have an impact.
What are the options for the treatment of SAD? Up until recently, the main treatment for SAD has been light therapy (LT), which uses special lamps that are 10 to 20 times brighter than ordinary indoor lights. Antidepressants may also be used in addition to light treatment or as an alternative in some cases.
Unfortunately, studies have shown that only 41 per cent of patients who have been diagnosed with SAD continued regular use of LT, a problem because LT suppresses symptoms for as long as treatment is ongoing. People who tried the therapy commented that ineffectiveness and inconvenience were the main reasons they stopped using LT.
Recent studies have shown that Cognitive Behaviour Therapy (CBT; a psychological treatment aimed at changing the way you feel by changing the way you think) can act in combination with LT or can be used as a treatment in its own right. If it is assumed that there are both physiological and psychological causes for SAD, a combination treatment with LT targeting the physiological factors and CBT targeting the psychological vulnerabilities would seem an appropriate course of action.
What does research say about CBT for SAD? In 2009, Kelly Rohan held pilot studies, which have shown promising results. In a randomised controlled trial, 61 adults with SAD were randomly assigned into four groups: CBT, LT, combination treatment (CBT+LT) or placed on a waiting list. Results showed that CBT combined with LT had a lower remission rate at the end of treatment than the wait list control. The researchers then did a follow-up study to examine longer-term outcomes. They found that CBT and combination treatment groups (CBT+LT) relapsed less than the light therapy group.
HOW TO BEAT THE WINTER BLUES
1. Become more active by doing positive activities: individuals with SAD withdraw from things that they would usually enjoy doing. Turn this around by engaging in a pleasurable activity. Keeping up your exercise and staying fit is an especially good activity to continue.
2. Learn to recognise what leads to different behaviour: a sense of foreboding and dread can be common even before the winter season hits, and this way of thinking keeps you feeling down. Learn to combat these feelings with positive responses. For example, see if you recognise the following thoughts and try replacing with the following:
– “I just want to sleep”
– “Even if I’m not thrilled by doing this activity, at least I’ll have done something.”
– “Things are too difficult”
– “I know that over time the more pleasant activities I do, the better I’ll feel.”
-“I won’t enjoy it anyway”
– “Yes, I do feel low right now but if I do something active I’ll be giving myself the chance to change that.”
Although seasonal changes may have an impact on your mood, day-to-day weather patterns and exposure to sunlight generally do not. However, we still ended up getting a north facing house and I am very happy with it.
CULTURE AND SAD
A study in Norway in 1998 pointed to some interesting cultural differences in the way we understand SAD. The study focuses on how Norwegians living in the northern city Tromsø, experience extreme seasonal change. This part of Norway experiences two months of total darkness during winter; so one might think that SAD would be widespread, yet this is not the case.
The study’s author Dr Cynthia M. Stuhlmiller conducted interviews with 28 participants. She noted that northern Norwegians simply accept seasonal changes and are socialised from childhood to prepare for the dark winter.
A connection to nature and its changing seasons is embedded in all aspects of their lives. One participant commented, “this will happen every year so we know how to manage it”. Social and cultural activities during the winter darkness are common and have been passed down the generations.
Acceptance to this way of life is evident in such Norwegian phrases as ‘vi tar det som det er’ which translates as, ‘we take it as it comes’. According to Stuhlmiller, this may help inform future approaches to therapy.