If you notice changes in your sleeping patterns, mood, and behavior in the late spring and summer months, you may experience summer onset seasonal affective disorder.

Seasonal affective disorder (SAD) is a type of major depressive disorder (MDD) that typically occurs in people during the winter months. Many leading theories suggest that changes in sunlight may be the underlying cause.

But SAD doesn’t only occur during the winter months. Summer onset SAD, which occurs during the late spring and summer months, may also relate to the sun and chemical changes in your brain.

If you experience summertime depression, you’re not alone. Resources are available to help you cope and possibly prevent summer onset SAD.

SAD, recently renamed major depressive disorder (MDD) with a seasonal pattern, affects anywhere from 1.4% to 9.7% of people living in North America.

According to the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR), MDD with a seasonal pattern is characterized by periods of depression during a few months of the year with periods of normal mood the rest of the year.

It often occurs with the change of season to winter, but it can occur during summer. According to the National Institute of Mental Health (NIMH), summer-pattern seasonal affective disorder is less common compared to winter-pattern seasonal affective disorder. But it’s difficult to say how many people it affects.

MDD with a seasonal pattern can include symptoms specific to major depressive disorder which can include:

  • having problems with sleep
  • feeling depressed most of the day, almost every day
  • having difficulty concentrating
  • experiencing changes in weight or appetite
  • having frequent thoughts of suicide or death
  • feeling sluggish or agitated
  • low energy
  • losing interest in activities you once enjoyed
  • feeling hopeless or worthless

Symptoms specific to MDD with a seasonal pattern may include:

  • insomnia (trouble sleeping)
  • episodes of violent behavior
  • restlessness and agitation
  • poor appetite, leading to weight loss
  • anxiety


MDD with a seasonal pattern typically involves the symptoms and signs of MDD with a few added symptoms. Signs your MDD may have a seasonal pattern include:

  • your depressive symptoms are worse during the summer than any other times of year
  • occurs for 2 or more years in a row
  • you experience symptoms of MDD

The exact cause of SAD is still unknown. Some theories on the causes of MDD with a seasonal pattern include:

  • reduced activity of the brain chemical (neurotransmitter) serotonin
  • people with SAD produce too much melatonin which increases feelings of sleepiness
  • sunlight may help to control the levels of molecules that help maintain balanced serotonin levels in the brain and may not work properly in people with SAD

Serotonin and melatonin both help regulate your sleep-wake cycle. Disruptions to this cycle could lead to sleep issues, changes in mood, and changes in your behavior.

It’s possible that increased levels of sunlight during the summer can lead to sleeplessness and changes in your mood or behavior.

Though anyone can develop MDD with a seasonal pattern, the National Alliance on Mental Illness (NAMI) suggests that women are more likely than men to develop the condition as are younger people.

If you have MDD with a summer onset, there are a few treatments available for you. Some standard therapies include:


Doctors will likely prescribe selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant that helps to regulate your serotonin levels.

Common forms available in the United States include:

A doctor may also prescribe bupropion, which is an extended release medication that may help prevent its onset.


Psychotherapy, more commonly known as talk therapy, involves speaking to a therapist about methods to deal with feelings associated with summer.

A subtype of psychotherapy, cognitive behavior therapy (CBT), may help to reset your way of thinking about summer and provide you with effective methods to cope with how you feel about the season.

Limited exposure to light

You may have heard about light therapy for SAD. The theory is that exposure to light during the winter may help to decrease the symptoms associated with winter onset SAD.

But with summer onset SAD, you will likely want to avoid this therapy and instead seek darkened rooms and areas.

Consider speaking with a mental health professional to determine exactly what therapies or combination of therapies may work best for you.

MDD with seasonal onset can affect your mood and behavior, but you can take some steps at home to help you cope.

Some suggestions include:

  • seek darkened rooms and limit exposure to direct sunlight
  • make rooms as cool as possible
  • get regular exercise
  • find a therapist toward the end of spring to work with
  • take steps to manage your stress, such as meditation or yoga

Keep in mind, experts indicate that currently no studies have shown universal success with starting therapies before the onset of your SAD symptoms. This could mean starting a therapy early may be more of a placebo effect.

Summer onset SAD is less common than winter onset SAD, but it’s a recognized subtype of MDD. The condition is likely related to sunlight and chemicals within your brain that cause changes in sleep, mood, and behavior.

You can often treat SAD with a combination of medications and psychotherapies, like cognitive behavior therapy. You may also find that seeking cool and dark rooms, exercise, and stress management may also help.

If you find that you start to feel depressed, have trouble sleeping, gain or lose weight, or have other symptoms that start around late spring or summer, you may want to speak with a doctor about what is going on. It’s possible that you’re experiencing summer onset SAD.