As the days get shorter and the seasons begin to change, it is not unusual to notice a shift in your energy, sleep, motivation, or mood.
Maybe getting out of bed feels harder. You are sleeping more but still feel tired. You have less motivation to exercise, socialize, or keep up with your usual routine. You may find yourself craving carbohydrates, withdrawing from people, or simply feeling unlike yourself.
For some people, these changes are temporary and mild. For others, they may be signs of Seasonal Affective Disorder (SAD), a form of depression that follows a recurring seasonal pattern.
What Is Seasonal Affective Disorder?
Seasonal Affective Disorder is a type of depression in which symptoms tend to begin and improve around the same seasons each year.
The most common form is winter-pattern SAD, with symptoms typically beginning during the fall or early winter and improving during the spring or summer. A less common form, summer-pattern SAD, can occur during the warmer months instead.
SAD is more than simply disliking cold weather or feeling less motivated when it gets dark earlier. Symptoms can last several months and may significantly interfere with work, school, relationships, self-care, and everyday functioning.
Signs Seasonal Depression May Be Affecting You
Seasonal depression can look different from person to person, but symptoms may include persistent sadness or low mood, loss of interest in activities you normally enjoy, low energy or fatigue, difficulty concentrating or making decisions, irritability, changes in sleep or appetite, social withdrawal, feelings of hopelessness or guilt, and difficulty keeping up with everyday responsibilities.
Winter-pattern SAD may be especially associated with oversleeping, increased appetite, carbohydrate cravings, weight gain, and feeling like you want to “hibernate” or withdraw from others.
It is also worth paying attention to patterns. Feeling tired for a few days after daylight saving time or having an occasional gloomy weekend does not necessarily mean you have seasonal depression. A recurring change in mood and functioning that appears around the same time each year deserves a closer look.
“Winter Blues” vs. Seasonal Depression
The distinction often comes down to severity, duration, and how much symptoms are interfering with your life.
You might experience a temporary drop in energy or motivation during the colder months and still be able to work, attend school, maintain relationships, and take care of yourself. Seasonal depression tends to be more persistent and disruptive.
If low mood, fatigue, withdrawal, sleep changes, or other depressive symptoms are lasting more than a couple of weeks or making it difficult to function normally, it may be time to talk with a mental health professional.
Why Does Seasonal Depression Happen?
There is not one single cause of SAD. Research suggests that seasonal changes in daylight may affect systems involved in mood, sleep, and the body’s internal clock. Changes involving serotonin and melatonin are among the factors researchers continue to study.
Reduced daylight may also disrupt the body’s normal sleep-wake rhythm, which can affect energy, sleep quality, concentration, and mood.
Seasonal depression is more common in areas with shorter winter daylight hours, but geography is only one factor. Personal and family history matter too. SAD occurs more frequently in people who also have conditions such as depression or bipolar disorder.
What Can Help?
The encouraging part is that seasonal depression is treatable. Treatment depends on the individual, the severity of symptoms, medical history, and whether another mental health condition is also present.
Light Therapy
Bright-light therapy is one of the most established treatments for winter-pattern SAD. A typical approach involves sitting near a 10,000-lux light box for approximately 30–45 minutes in the morning during the darker months.
Not every light marketed for “mood” is appropriate for SAD treatment, and light therapy is not right for everyone. People with certain eye conditions or who take medications that increase light sensitivity should discuss it with a healthcare professional first.
Psychotherapy
Therapy can be very helpful, particularly when seasonal changes lead to withdrawal, inactivity, negative thinking, or disruption of routines. A form of cognitive behavioral therapy specifically adapted for seasonal depression, called CBT-SAD, focuses on recognizing unhelpful seasonal thought patterns and increasing meaningful activities.
Behavioral activation can be particularly useful: rather than waiting until motivation returns, you intentionally schedule activities that create structure, connection, movement, or enjoyment.
Medication
Antidepressant medication may also be appropriate for some people with seasonal depression. For individuals who experience a predictable pattern year after year, a clinician may sometimes discuss beginning treatment before symptoms typically appear rather than waiting until depression has already become severe.
Bupropion XL is FDA-approved for prevention of recurrent seasonal depressive episodes in appropriate patients. Other antidepressants may also be used depending on the person’s symptoms, history, and clinical needs.
Medication decisions should always be individualized, particularly when there is a history of bipolar disorder, other psychiatric conditions, or multiple medications.
Protect Your Routine
The basics matter more than they sometimes get credit for. Maintaining a consistent sleep and wake schedule, regular physical activity, time outdoors during daylight hours, regular meals, adequate nutrition, social connection, and activities that give your week structure can all support mental health.
These habits do not replace treatment when someone is experiencing clinical depression, but they can be useful parts of a broader treatment plan.
What About Vitamin D?
Vitamin D often comes up in conversations about seasonal depression. Low vitamin D levels may occur alongside winter-pattern SAD, but research on vitamin D supplementation as a treatment for SAD has produced mixed results.
Rather than assuming that more vitamin D will treat seasonal depression, it is reasonable to discuss symptoms, diet, medical history, and whether laboratory testing or supplementation is appropriate with your healthcare provider.
When Should You Reach Out for Help?
Consider reaching out if seasonal changes are repeatedly associated with depression lasting more than two weeks, significant fatigue or oversleeping, loss of interest in things you normally enjoy, increasing isolation, difficulty functioning at work or school, significant appetite or weight changes, difficulty keeping up with basic responsibilities, or a pattern that returns during the same season each year.
You do not have to wait until symptoms become severe before asking for help. Recognizing the pattern early can make it easier to create a treatment plan before the most difficult part of the season arrives.
Seasonal Changes Shouldn’t Mean Putting Your Life on Hold
If you notice yourself becoming a different version of yourself every fall or winter, it is worth paying attention.
Seasonal depression is real, and effective treatment may include psychotherapy, medication management, light therapy, lifestyle changes, or a combination of approaches.
At ClearLane Behavioral Health, we provide virtual psychiatric evaluations, medication management, and mental health care for teens age 13+ and adults. Treatment is individualized based on your symptoms, medical history, current medications, and goals.
If changes in the season seem to be affecting your mood, sleep, motivation, concentration, or ability to function, scheduling an evaluation can be a good place to start.
Clarity. Healing. Growth.
If you are experiencing suicidal thoughts or a mental health crisis, call or text 988. For an immediate or life-threatening emergency, call 911 or go to the nearest emergency department.