While most people anticipate the arrival of summer with enthusiasm, some individuals experience a decline in mood and well-being as the days grow longer and warmer. This condition, known as reverse seasonal affective disorder (SAD) or summer SAD, presents a stark contrast to the more commonly understood winter SAD.
Summer SAD is a recognized mood disorder influenced by biological and psychosocial factors, where the light and heat of the season trigger mental health symptoms. Unlike winter SAD, which is thought to be caused by reduced light levels disrupting the regulation of mood hormones like serotonin and melatonin, the exact triggers for summer SAD are not fully understood. Experts suggest it may be related to disruptions in sleep patterns, changes in circadian rhythms, heat, humidity, and extended daylight hours affecting mood regulation in vulnerable individuals.
For some, excess light may lead to insufficient melatonin production, causing insomnia and jet-lag-like symptoms. This lack of melatonin can also trigger depressive illness or anxiety. While estimates suggest 80 to 90 percent of SAD cases follow the winter pattern, approximately one in ten individuals experience the summer variant. This summer form of SAD can be overlooked, with some individuals, like 26-year-old Charlotte Pennington, reporting that medical professionals initially dismissed their symptoms.
Symptoms of summer SAD can differ from winter SAD, which typically involves low energy, lack of motivation, increased sleep, and appetite. Summer SAD may present with anxiety, irritability, insomnia, restlessness, reduced appetite, weight loss, and heightened sensitivity to heat. The key indicator for summer SAD is a distinct change in mood, energy, and sleep patterns that recurs annually and interferes with daily life.
Charlotte, who has a history of anxiety and depression, began noticing a seasonal pattern in her symptoms around age 16. Her anxiety and depression worsened significantly from March and April, making her feel overwhelmed and reluctant to leave her home, even impacting her ability to attend college. As autumn approached and daylight hours decreased, she found her mood improving, with winter bringing a sense of decompression and increased happiness.
While winter SAD is often treated with bright light therapy to mimic sunlight, the specific environmental treatments for summer SAD are less established. Some theories suggest increased light levels contribute to disrupted sleep by suppressing melatonin production later into the evening. Light is a primary cue for synchronizing the body's internal clock, and changes in daylight can affect sleep, energy regulation, and emotional balance.
Other potential triggers for summer SAD include an immune response to higher pollen counts, as suggested by some research, or increased sensitivity to sunlight elevating stress hormone cortisol. High temperatures may also suppress thyroid function, leading to reduced motivation and lower mood. Social factors can also play a role, with summer often associated with increased social activity, travel, changes in routine, and holiday-related financial pressures, which can intensify distress for those experiencing low mood or anxiety.
Individuals with existing mental health conditions, such as anxiety disorders or bipolar disorder, may be particularly sensitive to seasonal shifts. Busy summer schedules can heighten feelings of being overwhelmed, and for those with bipolar disorder, seasonal changes can influence mood stability.
Treatment for summer SAD often involves cognitive behavioral therapy (CBT), which helps individuals identify unhelpful thought patterns, build coping strategies, and regulate routines. Research indicates that CBT tailored for SAD can be more effective for long-term outcomes than light therapy. For moderate to severe symptoms, antidepressant medication can also be beneficial. Charlotte currently takes antidepressants year-round and adjusts them as needed, while also employing strategies like using blackout blinds, avoiding socialising until after dusk, and wearing tinted glasses to limit light exposure.
Finding online communities has been a significant support for individuals like Charlotte, revealing a shared experience and validating the reality of summer SAD. Many affected individuals express a longing for the cooler, darker months and find solace in connecting with others who understand their unique challenges.