As the leaves change color and daylight begins to fade, some people sense a quiet shift in their mood. This isn’t just the “winter blues”; it could be seasonal affective disorder (SAD), a type of depression that follows a seasonal pattern. For many, symptoms begin in late fall or early winter and ease when spring returns. It’s a change in your mood and energy that can make daily life feel heavy.

It affects a lot of people! Estimates suggest that about 5% of the U.S. adult population experiences SAD. That’s over 16 million people. Another 10% to 20% may have a milder version of the condition. While it can happen to anyone, it is more common in women and in people who live far from the equator, where the winter days are very short.

Why does the shift in seasons bring on these feelings? The main cause is the reduced amount of natural sunlight we get in the winter. This lack of light can disrupt important things in your brain:

Melatonin levels

This hormone helps regulate your sleep.In the darker winter months, your body may start releasing melatonin at different times, which can leave you feeling sleepier and more sluggish than usual. 

Serotonin levels

This is a brain chemical that affects mood. Lower sunlight can lead to lower serotonin levels, which may contribute to low mood.

Your biological clock

The decrease in light can throw off your body’s natural clock, or circadian rhythm. This rhythm tells you when to sleep and when to wake up, and when it’s out of sync, it can cause tiredness and low energy.

If you or someone in your family has a history of depression, you may be more likely to develop SAD. The key takeaway here is that SAD is real, it’s common, and it’s not your fault. It’s tied to biological changes caused by the changing seasons.

Recognizing the signs: What SAD feels like

SAD shares many symptoms with other types of depression, but the important difference is the timing. It consistently starts and stops around the same time each year. If you notice these feelings starting right after the leaves fall and ending around the first warm days of spring, it might be SAD. Common symptoms of SAD can include:

Having low energy and fatigue

Feeling tired almost all the time, even after a full night’s sleep. This is the feeling that makes simple tasks feel like huge efforts.

Sleeping too much

You might feel a constant urge to sleep or find yourself oversleeping easily.

Gaining weight

Many people with winter-pattern SAD crave carbohydrates (like pasta, bread and sweets), which can lead to weight gain.

Losing interest

You may lose interest in activities you usually enjoy, including hobbies, time with friends, or work.

Feeling sad or hopeless

You’re in a sad, gloomy, or irritable mood most of the day, nearly every day.

Having difficulty concentrating

You find it hard to focus on work, school, or conversations.

It’s important to know that SAD can also happen in the summer, though this is much less common. If you have summer-pattern SAD, your symptoms might include trouble sleeping (insomnia), less appetite, and anxiety. The vast majority of SAD cases, however, are the winter type.

Finding light and relief in the darker months

The good news is that because SAD is often linked to a lack of light, it can often be helped with things that bring more “light” into your life, both literally and figuratively. There are several simple, powerful steps you can take to lessen the impact of SAD.

Try light therapy.

This is one of the most commonly used treatments for winter-pattern SAD. Light therapy involves sitting in front of a light box that gives off bright, broad-spectrum light, much brighter than normal indoor lamps.

• How it works

You typically sit near the box for about 20 to 30 minutes each morning. The bright light hits receptors in your eyes, which tells your brain to adjust those key chemicals (melatonin and serotonin). It helps reset your body’s clock, making you feel more awake and in a better mood.

• Important safety note

Always use a light box specifically designed for SAD treatment, and talk to your doctor or mental health expert before starting. Tanning beds are NOT a safe or effective way to treat SAD!

Get outside every day.

Even on cloudy or cold days, the amount of natural light outside is still much stronger than any indoor light. Making a point to go outdoors for at least 15 to 30 minutes every day can make a difference. Try to do it early in the morning, which helps maximize the impact on your body’s clock. Even moderate exposure to bright outdoor light, even in winter, can help regulate mood.

Exercise regularly.

Moving your body is a powerful natural mood booster. When you exercise, your brain releases chemicals called endorphins that create feelings of well-being. Regular physical activity can help lessen feelings of depression and anxiety. Aim for about 30 minutes of moderate exercise most days of the week. If you can combine exercise with getting outside, like taking a brisk walk, you get double the benefit!

Keep a steady routine.

When you’re feeling sluggish, it’s easy to let your schedule fall apart, but a consistent routine is your friend when fighting SAD. Your body loves consistency, especially during the winter when daylight hours are changing. Try to wake up and go to sleep around the same time every day, even on weekends. Stick to regular mealtimes and plan activities to look forward to. Having structure gives you something to rely on when your energy is low.

Consider vitamin D supplements.

Since sunlight is the best source of vitamin D, and we get less sun in the winter, many people become deficient, meaning they don’t have enough. Vitamin D plays a role in brain health and mood regulation. Talk to your doctor about testing your vitamin D levels. If they are low, your doctor may recommend a daily supplement. Low vitamin D levels are common, especially in darker months, and supplementing can support mood health.

When to seek professional help

Taking these self-care steps is important, but if your symptoms of SAD are severe, lasting a long time or deeply affecting your daily life, it may be time to reach out for professional help. Seeking help is a sign of strength, not weakness.

It’s a good idea to talk with a mental health professional or your doctor if:

• Your SAD symptoms are persisting or getting worse despite trying the light and lifestyle changes.
• You have thoughts of hurting yourself or others. (If this is happening now, please call or text 988, the 988 Suicide & Crisis Lifeline, for immediate support.)
• Your mood and low energy make it impossible to work, go to school or keep up with relationships.
• You turn to alcohol or drugs to cope with your winter mood.

A licensed therapist can help you through other treatments, such as talk therapy (psychotherapy) or medication, which can be very effective for SAD.

Talk therapy

Cognitive behavioral therapy (CBT) is often used for SAD. It helps you recognize and change the negative thoughts and behaviors that often happen during the winter months.

Medication

For some people, antidepressant medications can be helpful, especially if SAD is severe. Your provider can discuss if this is the right choice for you.

Living with SAD can make the winter months feel long and overwhelming, but please remember that it is a treatable condition. You don’t have to just “power through” until spring. Taking action now is the most powerful way to make the darker months feel a little brighter.

Turn to Guidelight Health to help you find hope on your path to mental wellness

If you’re seeking a compassionate, personalized approach, Guidelight is here for you. Our expert clinicians understand how seasons can shape your mood, and we provide care that meets you exactly where you are. Whether it’s light therapy, therapy sessions, medication or a tailored mix, we’ll work together to find what helps you feel brighter, more connected and more like yourself.

At Guidelight, you’re not just a diagnosis or list of symptoms; you’re a person with a story. And we’re honored to walk beside you in the darker months, bringing warmth, support and expert care every step of the way.

Everyone has a seat at Guidelight. Contact our team online or call us today for more information about seasonal affective disorder or to schedule an initial evaluation. We provide treatment across the country — and we’re always expanding. See if we offer care in your state, either online or at one of our local clinics.