Summer-pattern seasonal affective disorder may be less recognized than its winter counterpart, but mental health experts say some people experience recurring depressive symptoms during the warmer months, when longer days and higher temperatures can coincide with sleep disruption and other stressors.
Seasonal affective disorder (SAD) is a type of depression linked to changes in seasons.
According to the National Institute of Mental Health (NIMH), a number of people experience summer seasonal depression, even if most cases occur during fall and winter. The condition can be particularly difficult to identify because symptoms associated with summer-pattern SAD differ from those commonly linked to winter depression.
Summer Depression Can Look Different
People experiencing summer-pattern SAD may develop insomnia, reduced appetite, weight loss, anxiety, restlessness or agitation, according to the NIMH. The symptoms can emerge in spring or summer and typically improve during another season.
The NIMH said researchers do not yet know exactly what causes the seasonal pattern. Longer daylight hours, shorter nights and higher temperatures have been proposed as possible factors, although the agency notes that these explanations remain theories that require further study.
That uncertainty can make summer depression harder to distinguish from the effects of heat, disrupted routines or other seasonal changes.
Poor Sleep May Add to the Problem
High temperatures can make it more difficult to sleep, particularly during prolonged periods of hot weather. For people already vulnerable to seasonal depression, repeated sleep disruption may further affect mood and daily functioning.
Insomnia is itself associated with seasonal depression, according to the American Academy of Sleep Medicine. Excessive heat and humidity are potential environmental factors associated with the condition.
However, experts caution that experiencing poor sleep or feeling irritable during a heat wave does not necessarily mean someone has SAD. The disorder involves a recurring seasonal pattern of depressive episodes rather than temporary discomfort caused by weather.
Allergies and Other Stressors May Complicate Symptoms
Summer allergies can also coincide with changes in mood and sleep. Nasal congestion and other allergy symptoms may interfere with rest, while the physical discomfort of seasonal allergies can add to the burden faced by people already experiencing depression.
Allergies, however, have not been established as a direct cause of summer-pattern SAD.
Instead, several factors may overlap during the warmer months, potentially making symptoms more difficult to recognize. Changes in sleep, appetite and energy may initially be attributed to heat or seasonal routines rather than an underlying mental health condition.
A recurring pattern may be an important clue. People who consistently experience significant depressive symptoms during spring or summer and improve during other parts of the year may benefit from discussing those changes with a health care professional.
Treatment for SAD can include psychotherapy and medication. Light therapy is commonly associated with winter-pattern SAD, while treatment decisions for summer-pattern cases depend on an individual's symptoms and medical history.
The NIMH advises people experiencing persistent depression or significant changes in mood, sleep or appetite to seek professional care. Anyone experiencing thoughts of suicide or self-harm should seek immediate help.
As hotter temperatures and extreme heat events become more frequent, researchers continue to examine how environmental conditions affect mental health. For people who repeatedly struggle with depression during the summer, recognizing the seasonal pattern could be an important step toward receiving appropriate care.
