How seasonal affective disorder can impact bipolar disorder

Seasonal affective disorder (SAD) is often associated with depression, but it can also play a role in bipolar disorder. While many people with SAD experience depressive episodes during the winter, some may also experience seasonal mood shifts toward mania in the warmer months

In fact, research shows that up to 22% of people who have seasonal mood changes might actually have bipolar disorder. Understanding these seasonal shifts is key to receiving the right care and managing your symptoms during all seasons.

Can bipolar disorder be seasonal?

Bipolar disorder can affect people at any time of year, but research shows that seasonal changes can significantly affect you if you live with bipolar disorder. Both manic/hypomanic episodes and depressive episodes can worsen due to seasonal changes. 

Seasonal changes are so closely linked with bipolar symptoms that many experts believe that circadian and seasonal rhythm disruption may at least partly explain bipolar disorder. People are biologically able to detect seasonal changes, which often trigger symptoms of BD. Due to this, research has found that people living in areas where the sunlight shifts drastically with the seasons are more likely to develop bipolar disorder at a younger age.

Typically, people with bipolar disorder experience more manic or hypomanic symptoms in the spring and summer and more depressive symptoms during the fall and winter.

Summer mania

According to research, manic symptoms associated with bipolar disorder tend to peak in the summer. Some studies show an additional peak around the fall equinox.

The exact cause of the increased risk of manic symptoms during summer isn’t fully understood, but many experts think it may be related to sunlight exposure and temperature. Longer daylight hours in the summer can influence mood — particularly for people who live farther from the equator. Hotter temperatures could also contribute. 

Another possible factor is the disruption of routine. If you’re in school (or have children in school), summer vacation can provide a break — but it may also throw off your daily schedule. For example, during the school year, you might follow a strict morning and bedtime routine, but during summer, staying up late becomes more common.

Winter depression

Changes in sunlight and temperature could also explain why people with bipolar disorder tend to feel more depressed during the winter months. Research shows that up to 25% of people with bipolar disorder experience depressive episodes with a seasonal pattern, with most symptoms peaking between August and October. People with bipolar disorder are also more likely to be hospitalized for depression in the winter.

While this seasonal pattern is likely tied to changes in sunlight during the winter months, depression could also be related to lifestyle changes during the winter. Shorter days and colder temperatures — combined with the demands of the holiday season — can limit outdoor activities and throw off routines, which can contribute to depression.

What’s the difference between bipolar and seasonal affective disorder?

Seasonal affective disorder, or SAD, is a mental health condition that causes symptoms of depression during certain times of the year. It most commonly refers to seasonal depression, but it can describe bipolar disorder as well due to how the change of seasons play a role in when symptoms emerge.

Unfortunately, bipolar disorder is often initially misdiagnosed as depression in winter months. For example, you might see a health professional when you feel depressed in the winter. After learning that there’s a seasonal pattern to your depressive symptoms, they may diagnose you with depression with seasonal pattern (SAD).

What they may not know is that you not only feel less depressed during the summer months but you also feel manic. This would be a clear sign of bipolar disorder, but if you only seek support during a depressive episode, your provider might not put the pieces together. 

What causes some people to have both SAD and bipolar disorder?

Researchers are still studying the exact causes of SAD and bipolar disorder, but some known factors may contribute to your risk of developing both.

Risk factors for developing both SAD and bipolar include: 

• Living far from the equator: People living in places where seasonal changes in sunlight are more dramatic (rapid or abrupt changes over a long length of time) are at higher risk for both depression and bipolar disorder with seasonal patterns. The lack of sunlight in winter can trigger depressive episodes in both conditions. And the increase in sunlight (and temperature) can contribute to mania/hypomania for people with bipolar disorder.
• Family history of mood disorders: A family history of depression, SAD, or bipolar disorder increases your likelihood of developing seasonal depression or bipolar disorder. 
• Age: Both SAD and bipolar disorder often emerge in young adulthood. People in their teens and 20s are at higher risk of experiencing mood changes tied to seasons or bipolar symptoms. Those who live in areas where there are rapid seasonal changes are at risk of developing bipolar disorder five years earlier.
• Existing depression or mental health conditions: People with a history of depression or other mental health conditions are more likely to experience seasonal mood shifts. For people with bipolar disorder, this can mean depressive episodes during the winter and periods of mania or hypomania in the summer.
• Disrupted circadian rhythms: The body’s internal clock, which regulates sleep and mood, is sensitive to changes in sunlight. Disruptions in circadian rhythms caused by shorter days in winter can worsen symptoms of both SAD and bipolar disorder.

Four ways to cope with both SAD and bipolar disorder

Living with seasonal depression or bipolar disorder can make certain times of the year feel much more difficult than others. But with the right support, including professional treatment and lifestyle changes, you can live a balanced life through every month of the year.

1. Establish a routine

Having a regular, healthy routine is one of the best ways to manage mood shifts that can come along with seasonal changes. For example, keeping consistent times for meals, maintaining a clear bedtime routine, setting specific times to exercise, or planning time for relaxation and hobbies can create a stable structure in your day. 

Setting a schedule can help anchor your mood and provide a sense of predictability even when external factors, like daylight, are changing. 

2. Try light therapy

Light therapy is one of the most effective ways to deal with seasonal depression. This treatment method involves exposing yourself to more light in the winter months to address circadian rhythm imbalances and reduce symptoms of depression. Research has also found that light therapy can reduce winter depression for people with bipolar disorder. 

For some people, light therapy may trigger mania or hypomania, although research has found that this risk isn’t clinically significant. If you’re concerned about this side effect or experience symptoms of hypomania or mania while doing light therapy, talk to a healthcare provider right away.

3. Prioritize sleep

Your circadian rhythm is closely linked to seasonal mood changes. It’s important to regulate your circadian rhythm, and one of the best ways to do this is by getting regular, restful sleep each night. Sleep and mental health are also deeply connected. 

Follow research-backed sleep hygiene tips. Try to go to bed and wake up at the same time every day, regardless of the time of year. Pay particular attention to how your sleep changes as the seasons change. People with seasonal mood conditions may be sensitive to hypersomnia, or sleeping too much, during the winter months. Not sleeping enough (or at all) during the summer could be a sign of a manic episode.

4. Seek professional support

SAD and bipolar disorder are both mental health conditions that can be treated. Talk therapy methods — like cognitive behavioral therapy (CBT) — can help you cope with symptoms of depression or bipolar disorder, whether your symptoms are seasonal or not. A method called interpersonal and social rhythm therapy (IPSRT) can help you maintain routines, which can reduce symptoms of SAD and bipolar disorder.

You may also benefit from medication to manage your mood, especially if you live with bipolar disorder. Talk with your doctor or mental health professional to learn more about medication options. 

Find care with Rula

Life can be hard when your mood changes drastically with the seasons. If you live with seasonal affective disorder as a part of bipolar disorder, it could feel like your mood swings are out of your control. But with the support of a therapist, you can learn new strategies to cope with your mood and live a more balanced life.

Rula has connected patients and therapists for millions of successful therapy sessions. Whether you live with seasonal depression, seasonal mania, or both, Rula can help.

Find a therapist with Rula