Lana del Rey once said that she has the summertime sadness. We have heard about the winter blues and the Seasonal affective disorder (SAD), but Lana (unintentionally and in a completely different context) brings up reverse SAD. Summer is a joyful season for most people, they go out to parks, soak their skin with the sunlight, welcome the sun with open arms. For others, it triggers summer depression or SAD in the summer.

Seasonal affective disorder tends to occur as the days grow shorter and colder as the fall and winter progress. Biological clocks, levels of serotonin, production of hormones are altered which can affect our mood. According to the National Alliance on Mental Illness, about 10% of the SAD cases are affected with reverse SAD. Unfortunately, reverse SAD has been understudied and not much is known about its causes. In theory, when talking about seasonal affective disorder, the disorder accounts for the disorder expressed in every season, not only late fall and winter. However, the studies about SAD focus almost exclusively on fall/winter, which could be a problem when no distinction among seasons is made, and it is thought that summer depression and winter depression are the same.

In 1987, Thomas A. Wehr and colleagues described the disorder at an APA convention as “Seasonal Affective Disorder with Summer Depression and Winter Hypomania,” and in 1991 Wehr suggested that the two types of depression might be two different disorders. When comparing both disorders, the only similarities among them are the feelings of sadness, anxiety and distress. While people with winter SAD crave carbohydrates, oversleep and  withdraw from social interactions, interestingly enough, people who suffer from summer SAD or reverse SAD tend to experience insomnia, typically have poor appetite, and seem to have an increased sex drive.

Most theories regarding the origins of SAD come from the fact that there are shorter days, and colder weather. Less exposure to the sunlight can disrupt the production and secretion of melatonin. In humans, melatonin is secreted by the pineal gland that regulates other hormones and maintains the body’s circadian rhythm. A circadian rhythm is a 24-hour period that plays a critical role with sleep/wake periods. There is an inverse relationship between light and melatonin: when there is stimulation from light, the signal instructs the pineal gland to suppress melatonin production, and when the evening comes the lack of stimulation is signaled to the pineal gland and the secretion of melatonin increases. Since the circadian rhythm of melatonin secretion is so tied to the day and night cycle, the daily duration of the secretion is shorter during the summer (shorter nights), and longer during the winter (longer nights). Therefore, too much melatonin and a circadian rhythm that has been disrupted might be the cause of winter SAD. Support for the theory comes from the success of therapies involving the exposure to artificial sources of light in patients. The opposite could be said about summer SAD, but there is not enough evidence with treatments where melatonin has been administered to patients.

Other theories regarding the origin of summer SAD involve the elevated temperatures of summer, but not enough data supports that theory either. Alvaro Guzman suggested another hypothesis involving allergies. Guzman said that aeroallergens produce inflammation in the respiratory airways, and inflammation triggers depression in vulnerable individuals. Since pollen is absent during the winter, he thought that there might be a relationship between mood and presence of pollen, which could potentially explain the origins of reverse SAD. In a study published in the Journal of Affective Disorders, Guzman found an association between mood worsening during periods of high pollen and “greater dispositional seasonality” (Guzman et al., 2007). He concluded that people who experienced bad mood when they were exposed to more pollen, were more likely to suffer from reverse SAD.

Although the correlation found by Guzman is fascinating, what happens to those who hate sunny weather yet don’t suffer from any allergies? Other theories suggest that disrupted schedules (school is out, and routines can be broken), body image issues (warmer weather means fewer layers, which could potentially cause anxiety and distress on people with body image issues) or financial worries (summer can be expensive) might be the cause. It is likely that there are multiple origins for summer-SADness. It could be the awful heat, the brightness of the day, or allergies. So the next time someone says that they hate sunny days, take a moment to consider that their circadian rhythm might be compromised, or they might have awful allergies. Thankfully, studies on reverse SAD are becoming more numerous with time, and it has been recognized that SAD and reverse SAD are different disorders, with different symptoms and potential different treatments.

References:

A. K. (2012, July 9). The Role of Melatonin in the Circadian Rhythm Sleep-Wake Cycle. Retrieved February 6, 2016, from http://www.psychiatrictimes.com/sleep-disorders/role-melatonin-circadian-rhythm-sleep-wake-cycle

Goldman, J. G. (2014, June 4). Reverse Seasonal Affective Disorder: Why Do People Get SAD in Summer? Retrieved February 6, 2016, from http://gizmodo.com/reverse-seasonal-affective-disorder-why-do-people-get-1585673865

Guzman, A., Tonelli, L. H., Roberts, D., Stiller, J. W., Jackson, M. A., Soriano, J. J., … Postolache, T. T. (2007). MOOD-WORSENING WITH HIGH-POLLEN-COUNTS AND SEASONALITY: A PRELIMINARY REPORT. Journal of Affective Disorders, 101(1-3), 269–274. http://doi.org/10.1016/j.jad.2006.11.026

Lewis, J. G. (2015, January 14). Reverse Seasonal Affective Disorder: SAD in the Summer. Retrieved February 6, 2016, from https://www.psychologytoday.com/blog/brain-babble/201501/reverse-seasonal-affective-disorder-sad-in-the-summer

What Is Seasonal Affective Disorder (SAD)? (n.d.). Retrieved February 6, 2016, from http://www.medicinenet.com/seasonal_affective_disorder_sad/article.htm