Sleeping poorly, losing appetite, feeling agitated precisely in the months in which the calendar seems to impose holidays, sunsets and a regulated amount of happiness. It happens, and for some people it goes far beyond disliking August. Seasonal affective disorder can also appear in spring and summer, with different characteristics from the much better known winter form. In medicine we talk about summer-pattern seasonal affective disorderor summer SAD. “Summertime Sadness” works great as a pop label. As a diagnosis, decidedly less.
In fact, the US National Institute of Mental Health classifies SAD as a form of depression characterized by episodes that follow a recurring seasonal pattern and generally last four or five months. The summer variant is recognized, although much less common than the one that appears between autumn and winter.
Summer SAD isn’t simply “hating the heat”
The difference lies above all in the persistence and recurrence of symptoms. A bad week in August, boredom while everyone else seems to be on a sailboat and impatience towards yet another tropical night are not enough to talk about seasonal affective disorder.
According to the NIMH, for a diagnosis, depressive episodes must occur in a given season for at least two consecutive years and be more frequent during that period than at other times of the year. General symptoms of depression may include persistent sadness, loss of interest in usual activities, tiredness, difficulty concentrating and feelings of hopelessness. In the summer form, insomnia, poor appetite, weight loss, agitation and anxiety are particularly reported.
And it’s rare. In a study conducted in the Netherlands on 5,356 people selected from population registers, published on Biological Psychiatryapproximately 3% of participants met the criteria used for winter SAD and just 0.1% for summer SAD. It is data from 1999, referring to that specific population and therefore unsuitable to become a universal percentage, but it shows well how the hot variant is less frequent.
Heat, light and sleep: what we really know
On summer SAD the research still has several blank spaces. The winter form has been studied much more and even the biological mechanisms proposed for the summer remain partly hypothetical.
The NIMH indicates alterations in melatonin and circadian rhythms among the possible leads. Very long days, short nights and high temperatures can disturb sleep; in predisposed people this set of factors could contribute to depressive symptoms. The same institute specifies, however, that these hypotheses on the summer variant have not yet been systematically tested. A caution that is small in form and rather important in substance.
On the more general relationship between high temperatures and mental health, however, the data is more consistent. A study published in JAMA Psychiatry analyzed nearly 3.5 million emergency room visits in the United States during the warm months between 2010 and 2019, covering more than 2.2 million insured people. On days classified as extremely hot, the rate of mental health visits was 8% higher; the association also appeared for mood disorders, anxiety, stress and self-harm. The study is observational: it shows an association, it does not prove that heat directly causes those disorders.
They are two phenomena that must therefore be kept distinct. Heat can take a toll on mental health even in people who don’t have summer SAD; having a hellish week because you sleep four hours a night with 30 degrees in the room, on the other hand, does not automatically equate to suffering from seasonal depression.
When summer should necessarily be beautiful
Then there is a component that is less measurable with a thermometer: summer arrives accompanied by a rather cumbersome social script. Holidays, bodies in costume, travel, relationships, aperitifs, photographs. In social media, editing is particularly efficient: the sea and the sunset remain, the mortgage, the work shift and the mosquitoes easily disappear.
This pressure can contribute to frustration, social comparison and a sense of isolation, especially for those who are already going through a difficult time. Here too, it is important to avoid attaching a diagnosis to any seasonal ailment. The NIMH explicitly distinguishes seasonal depression from moods related to predictable calendar stress: SAD requires a true recurrent depressive pattern.
This is probably also why “Summertime Sadness” has become such an effective expression. It brings together very different experiences under two words: the loneliness of August, the emptied city, the comparison with apparently perfect lives, heat insomnia and, in a small part of people, a real depressive disorder.
Furthermore, for summer SAD there is currently no specific treatment comparable to the light therapy used especially in the winter form. The NIMH indicates psychotherapy and antidepressant drugs among the options used for depression, also with a seasonal trend; However, diagnosis and treatment must be evaluated with a professional, especially when the symptoms persist, interfere with work and relationships or return punctually at the same time of the year.
In short, summer does not have antidepressant properties by decree. For some it means holidays. For someone else, broken sleep, heat and a mood that plummets just as the obligation to have fun seems to be starting all around. The difference between a bad summer and summer SAD is duration, symptoms and recurrence. Fortunately, the swimsuit does not yet fall within the diagnostic criteria.
