Seasonal affective disorder, or SAD, is a change in mood or mental state caused by a change in seasons. The most common form of SAD is experiencing depression as winter approaches, but some people experience depression in the summer and people with bipolar disorder sometimes experience manic episodes when the weather turns hot. Although SAD is often described as the winter blues, it’s important not to dismiss the symptoms, especially if you are recovering from a substance use disorder. 

While it’s normal to feel a bit more subdued during the winter months, don’t ignore the symptoms of depression. These may include depressed mood, irritability, loss of interest in things you used to enjoy, fatigue, disturbed sleep, physical aches, slow movements, isolation, poor concentration, feelings of hopelessness or worthlessness, and thoughts of suicide or death. In winter SAD, excessive sleep is more common, whereas, in summer SAD, insomnia is more common. And while lack of appetite is more common with depression, winter SAD typically leads to increased appetite, especially for carbs, and weight gain. Depression symptoms are serious in themselves and they may increase the risk of relapse for people recovering from substance use issues. 


What causes SAD?

Winter SAD is thought to have several causes. First, the shorter days disrupt your circadian rhythm. People in northern latitudes especially often wake up in the dark, spend most of their daylight hours inside at work, then go home in the dark. The problem is that your body needs some exposure to sunlight to maintain a proper circadian rhythm. The sun signals it’s time to wake up in the morning and sun exposure increases melatonin levels throughout the day, helping you sleep at night. Without sun exposure, your circadian rhythm gets flattened out, which is also a characteristic of depression. 

Sun exposure also increases levels of the neurotransmitter serotonin, which is linked to positive mood. With too little sunlight, you may also have too little serotonin. People also tend to be less active in the winter and lack of exercise, especially outdoor exercise, may affect your mood. Finally, December is the holiday season for most people living in northern latitudes, which may mean overindulgence in sweets, which can cause inflammation and aggravate depression. Holidays are also stressful for many people, with greater financial and family obligations.

Some people are more vulnerable to SAD than others. Women are about four times as likely as men to experience SAD and anyone with a history of major depression or bipolar disorder is also at greater risk. 


What can you do about SAD?

If you’re experiencing symptoms of SAD, take it seriously. Talk to your doctor or therapist about it to figure out whether you’re feeling normal winter blues or major depression. If you are experiencing depression, the standard treatment is psychotherapy, possibly with the aid of an antidepressant, typically an SSRI. These will improve symptoms for most people. There are also some additional ways you can offset the effects of the season on your mood. 


Light therapy

Since a disrupted circadian rhythm is thought to be a primary cause of winter SAD, light therapy is often an effective way to mitigate the symptoms. Typically, you would spend about 30 minutes each morning at home or at work sitting in front of a full-spectrum light box. This signals your brain to wake up and helps keep your circadian rhythm on track. Recent research has discovered that taking a hot bath in the afternoon can significantly reduce symptoms of depression. The researchers believe this is because increasing core body temperature in the middle of the day helps restore participants’ circadian rhythm, leading to better sleep. So this may be another way to get your circadian rhythm back on track.


Vitamin D

Vitamin D is thought to play a role in depression in general and winter SAD in particular. As noted above, people in northern latitudes often have minimal exposure to sunlight in the winter months. Unfortunately, most of our vitamin D is produced in the skin when it’s exposed to sunlight. Lightboxes don’t provide the powerful UV rays that produce vitamin D so they’re no help in that regard. We don’t quite understand how vitamin D is related to depression, but we do know that vitamin D levels are low in people with depression and that supplementation improves symptoms in depressed people, especially people with SAD. The catch is that it looks like you need a pretty high dose of vitamin D to see improvements–one study administered a one-time dose of 100,000 IU–and excess vitamin D can have negative side effects over time. So it’s best to consult with your doctor about vitamin D supplementation and monitor your levels with occasional blood tests. 



As noted above, December is the holiday season, and most people eat more unhealthy food even as the days get shorter and colder. While an occasional treat is fine, beware of “It’s the holidays!” rationalizing. Sugar is inflammatory, which recent research shows may cause or aggravate depression. Despite the temptations of the holidays, try to stick to a sensible diet of mostly fruits, vegetables, whole grains, beans, nuts, legumes, and lean meats.



When it’s cold and dark outside, it’s tempting to want to stay inside where it’s warm and cozy. Unfortunately, spending too much time bundled up on the couch can take a toll on your mood. Try to get a bit of exercise outside if you can, even if it’s just a short walk. Consider joining a gym so you can have a warm place to exercise. As a bonus, you’ll get a bit of social contact at the gym, especially if you join an exercise class. The extra social contact may also improve your mood. 

If you have a loved one who is struggling with addiction, Hired Power and our team of dynamic, experienced recovery professionals are here to guide you every step of the way. We offer many services, including helping you choose the best treatment program and transitional services, including interventions, sober monitoring, and personal recovery assistants. Call us today for information on our recovery services: 800.910.9299.