Have you considered clinical trials for Seasonal affective disorder (SAD)?

We make it easy for you to participate in a clinical trial for Seasonal affective disorder (SAD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

What is seasonal affective disorder?

Seasonal affective disorder (SAD) is a subtype of either major depressive disorder or bipolar disorder. Its key feature is a pattern of major depressive episodes triggered by seasonal changes.

Most people with SAD are affected during autumn and winter. Their symptoms resolve in the spring and summer, and return the following autumn.

Seasonal affective disorder in the summer 

A small number of people with SAD experience the opposite seasonal pattern. Their symptoms develop in the spring, continue through the warm summer months, and then resolve in autumn. This condition is known as either spring-onset SAD, summer SAD, or reverse SAD.

What causes summer seasonal affective disorder? 

The exact causes of SAD, especially summer SAD, are unknown. Experts believe various factors can trigger it and contribute to the symptoms. People with SAD may have higher sensory processing sensitivity, which could make them more susceptible to environmental changes that occur in the spring and summer.

Family history

A family history of SAD or other mood disorders might increase the risk of developing SAD. There may also be a genetic component involved.

Sunlight and its effect on hormones 

Too much sunlight can affect your circadian rhythm (biological clock). Light inhibits the production of melatonin, the hormone that controls the sleep-wake cycle. 

Due to this, the longer days of summer (more hours of sunlight) can lead to less production of melatonin, which in turn disrupts the sleep-wake cycle. This could be why people with summer SAD complain of feeling overly alert and agitated. 

Heat and humidity

Heat and humidity in summer can make you irritable, agitated, or anxious. Although this isn’t responsible for directly causing SAD, experts believe that the abundance of heat during summer can disrupt functions and worsen mood-related symptoms. 

Geographical location

Some experts suggest that living closer to the equator can increase the risk of developing summer SAD. These areas have more hours of sunlight each day.

This is the opposite of how living far from the equator can contribute to developing winter SAD.

Allergies and pollen

Preliminary studies¹ have suggested that certain allergens, such as airborne pollen, are associated with self-reported worsening of mood, and may contribute to summer SAD. 

A study found that those who experienced a worsening of their mood when the pollen count was high, were more likely to meet the diagnostic criteria for summer SAD.

Pollen can induce a strong inflammatory response in people with allergies. The inflammatory triggers are associated with mood-worsening, and a study showed that this was experienced in two-thirds of participants.

How is summer SAD different from winter SAD?

Summer SAD can bring some of the same symptoms as winter SAD. These include:

  • Feeling sad and depressed almost all the time

  • Losing pleasure in your interests and hobbies

  • Having feelings of hopelessness, worthlessness, or guilt

  • Thinking about death and suicide

  • Having difficulty concentrating 

Aside from these generalized symptoms, summer SAD has some symptoms that are different from winter SAD.

Summer SAD looks different in everyone, but the following symptoms are common: 

Difficulty sleeping

People with summer SAD often experience insomnia (difficulty sleeping).

This is likely due to the longer days and shorter nights, which results in melatonin being produced later at night, and less melatonin being produced overall.

Low appetite

It's common for people with summer SAD to lose their appetite.

Unintentional weight loss

As a result of eating less due to loss of appetite, some people with summer SAD experience unintentional weight loss.

Mood and behavior

People with summer SAD commonly feel anxious, restless, agitated, or a combination of these feelings. Some people also experience suicidal thoughts. Studies have shown that suicide rates are more common in the spring and summer, possibly due to the dysregulation of serotonin and melatonin, and the impact of airborne pollen on mood.

These symptoms of summer SAD differ from winter SAD, which is associated with:

  • Weight gain

  • Increased appetite

  • Cravings for carbohydrates

  • Excessive sleep

  • Depressed mood and fatigue

The diagnostic criteria for summer SAD 

Some of the key elements of summer SAD needed for a diagnosis include:

  • Symptoms are triggered in the spring and summer months

  • Symptoms recur for at least two consecutive years in the same season

  • The symptoms remit in the opposite seasons

  • The SAD depressive episodes must be more frequent than any other depressive episodes that have previously occurred

How to treat summer seasonal affective disorder 

Summer SAD is rare and often goes undiagnosed and untreated. Compared to winter SAD, there have been far fewer studies specifically about summer SAD. This means there are no specific treatments for summer SAD.

Since summer SAD falls under the category of major depressive disorder or bipolar disorder, it's often recommended that summer SAD should be treated using the same treatments that are used for unipolar major depression.

Like other mental health conditions, there are different treatments for seasonal affective disorder. Some types may be safer and more effective for you than others.

Before beginning any treatment, always speak with your doctor.

The types of treatment for summer SAD can involve one or more of the following. 

  • Pharmacotherapy (medications)

  • Psychotherapy (talk therapy)

  • Complementary treatments, such as lifestyle changes

A combination of medication and psychotherapy is thought to be most beneficial in treating depression, and therefore summer SAD, since these conditions are treated in the same way.


The medications used to treat nonseasonal depression, such as antidepressants, are also thought to be effective for treating summer SAD.²

Some of the medications used to treat depression include:

  • Selective serotonin reuptake inhibitors (SSRIs), such as fluoxetine and sertraline

  • Serotonin-norepinephrine reuptake inhibitors

  • Atypical antidepressants, including bupropion (recognized for its specific ability to treat SAD)

  • Serotonin modulators

  • Tricyclic antidepressants

  • Monoamine oxidase inhibitors

Antidepressants create a balance between chemical messengers in the brain, such as serotonin and norepinephrine. In depressive conditions like SAD, these chemical messengers are disrupted.

Who should use medication for summer SAD?

Medication is recommended for people with SAD who:²

  • Have previously responded well to antidepressants

  • Are at high risk of suicide

  • Have experienced a substantial reduction of quality in their daily life and relationships

  • Have previously had moderate to severe recurrent depression

  • Have not responded to other types of therapy, likely psychotherapy in summer SAD

  • Choose it as their preference

It may be helpful to start taking your medication before your symptoms begin every year. For summer SAD, this will likely be in the early spring (March in the northern hemisphere, or September in the southern hemisphere). Most people are advised to continue medication until autumn, when their symptoms naturally remit.

You should follow all professional advice given to you. This includes taking the correct dose and staying consistent throughout the season that affects you, to prevent negative side effects which could hinder the positive effect of antidepressants.

Some people experience adverse effects from antidepressants, so they are not the best solution for everyone. Fortunately, there are several other options for treating summer SAD.

Melatonin therapy 

Melatonin is a hormone produced in the brain. It helps to regulate the sleep-wake cycle and circadian rhythm (the biological clock). It causes tiredness, which helps you fall asleep. 

Melatonin is produced at night when it is dark. This means that less is produced in the summer when the days are longer and nights are shorter. 

Melatonin therapy involves taking tablets that contain melatonin. This can help regulate the sleep-wake cycle and biological clock, which is disrupted in summer SAD. 

Melatonin could be used to help manage insomnia. In turn, this could improve the onset, duration, and quality of sleep.³ This can be beneficial if you suffer from sleep-related symptoms of summer SAD.


Cognitive-behavioral therapy (CBT) is a form of psychotherapy.

CBT is centered around the connections between your thoughts, feelings, and behavior. Many people with depression find their problems overwhelming and are unable to deal with them in a healthy way.

CBT helps you to:

  • Identify and challenge your negative thoughts

  • Replace negative thoughts with positive ones

  • Identify engaging, pleasurable, and healthy actions or behaviors, such as establishing an exercise routine, or a sleep schedule

  • Reduce avoidance behavior

  • Learn healthy coping mechanisms for dealing with seasonal affective disorder. This can help to reduce your current symptoms, and possibly prevent future symptoms, as you will know how to respond to negative thoughts and behaviors.

The studies of CBT on SAD have mostly focused on winter SAD.⁴ However, CBT is a popular treatment for many mental health conditions, including nonseasonal depression and anxiety, so it is also expected to be beneficial for people with summer SAD.

Exposure to sunlight and temperature 

People with summer SAD can get relief from their symptoms by altering the amount of sunlight and the temperature of their environment. 

To do this, you could:

  • Limit your exposure to natural sunlight to a maximum of 13 hours each day

  • Use air conditioning at night, if you have it

  • Spend time in the shade when you are outside

Improving your sleep

Since insomnia is a common symptom of summer SAD, it is important to optimize your sleep schedule. This can help to improve the quality of your sleep and the symptoms associated with insomnia that can come with SAD. 

You can do this by:

  • Reducing your light exposure before bed

  • Switching off your devices a couple of hours before bed, so you don’t hinder the production of melatonin

  • Keeping your room dark, for example by using blackout curtains or an eye mask

  • Keeping your room temperature cool


Many people who struggle with depression, including SAD, find it difficult to carry out everyday tasks and hobbies. 

Moving your body can greatly improve your mental health, as exercise increases brain chemicals such as dopamine and serotonin, which can improve mood.

Keep in mind that people with summer SAD may find it more beneficial to exercise indoors, in a cool environment that isn’t too sunny. 


A loss of appetite is common in people with summer SAD. It is important to eat enough calories so that you can keep your energy levels up.

In the afternoon you should avoid food and drink that can keep you awake at night, especially anything containing caffeine.

What to avoid during treatment

Since summer SAD is triggered by longer days and increased hours of sunlight, some of the treatments used to help winter SAD are not suitable for summer SAD.

For example, light therapy⁵ is a common treatment for winter SAD when people do not get enough natural sunlight, but should not be used for summer SAD.

Seeking help

Seeking help for any mental health condition is important. The first step is to visit a trained medical professional, like your family doctor or a therapist.

It's best to see your family doctor first if possible so that they can run tests and rule out other medical conditions. Be sure to follow all their advice.

Can you prevent summer seasonal affective disorder?

Since the symptoms of summer SAD tend to begin at a similar time every year, generally during the spring, most people know what to expect and can prepare themselves for the recurrence of symptoms.

Although you may not be able to fully prevent seasonal affective disorder, you could make lifestyle changes or start taking medication in the lead-up to summer, if your doctor recommends it. This could reduce the impact of SAD on your mood, appetite, and energy levels.

The lowdown

Seasonal affective disorder can make the long, hot summer days difficult to get through. It can feel isolating, and the fact that everyone else seems to be enjoying their summer may make you feel alone.

Fortunately, it doesn’t have to be that way. There are several treatments that you can use to manage your summer SAD symptoms and improve your well-being.

Have you considered clinical trials for Seasonal affective disorder (SAD)?

We make it easy for you to participate in a clinical trial for Seasonal affective disorder (SAD), and get access to the latest treatments not yet widely available - and be a part of finding a cure.

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