Seasonal Affective Disorder 

Seasonal affective disorder (SAD) is a form of depression that is cyclical or seasonal in nature. Those who live with SAD usually experience mood changes and symptoms similar to depression, certain times of the year. Typically, the symptoms occur during the fall and winter months, due to diminished exposure to sunlight and warmer weather, in conjunction with more sedentary hours indoors. Symptoms usually improve with the onset of warmer weather once Spring arrives. According to the American Psychiatric Association, the most challenging months tend to be January and February. Though, in rare cases, certain individuals experience SAD in the summer.

If you, or a loved one currently lives with SAD, the symptoms can be distressing and overwhelming and can interfere with daily functioning. It is therefore crucial to have your condition properly diagnosed, so proper treatment and recovery can be implemented. SAD has been linked to a biochemical imbalance in the brain prompted by shorter daylight hours and less sunlight in winter. As seasons change, people experience a shift in their biological internal clock or circadian rhythm that can cause them to be out of step with their daily schedule. SAD is more common in people living far from the equator where there are fewer daylight hours in the winter.

Symptoms and Diagnosis

SAD can begin at any age, but typically starts when a person is between ages 18-30, and is more common in women than men. Symptoms commonly associated with SAD include, but are not limited to:

  • Fatigue and change in sleep patterns (associated with oversleeping) 
  • Weight gain (in conjunction change in appetite, overeating and craving sugary or high carbohydrate foods)
  • Feeling sad, or depressed
  • Loss of interest or pleasure in activities previously enjoyed
  • Loss of energy or increased fatigue, despite increased sleep hours
  • Increase in purposeless physical activity (e.g., inability to sit still or pacing), or slowed movements or speech (these actions must be severe enough to be observable to others)
  • Feeling worthless or guilty
  • Difficulty thinking, concentrating, or making decisions
  • Thoughts of death or suicide 


There are several effective treatment methods for SAD. Typically this includes one, or some combination of the following: light therapy, antidepressant medication, therapy. Symptoms tend to improve on their own with the change of season, but usually improve faster with some course of treatment.

1. Light therapy 

This involves sitting in front of a specifically designed very bright light (that filters out harmful ultraviolet (UV) rays). Treatment usually involves a minimum of 20 minutes per day in the morning. People tend to experience improvement in symptoms from light therapy within 1-2 weeks of commencing treatment. To maintain the benefits and prevent relapse, it is recommended that treatment continues daily through the winter months, even after experiencing improvements in symptoms. Symptoms tend to recur seasonally, it is therefore advisable to begin light therapy in early fall, to lessen severity of symptoms, or to prevent symptoms altogether.

Individuals suffering from SAD can also experience improvement from increased exposure to daily natural sunlight alone. It helps to spend some time outside every day. Additionally, try to arrange your home or office so that you are exposed to a window during the day. Ensure that you also prioritize general health and wellbeing, make time for regular exercise, eat healthily, get sufficient sleep, stay active, and remain connected with loved ones and the community. This can involve volunteering, participating in safe group activities, and spending time with friends and family (even digitally, or at a distance if required).

2. Therapy

Therapy, particularly 1:1 talk therapy with a specialist involving cognitive behavior therapy (CBT), is highly effective in treating SAD. Therapy is often undertaken in conjunction with prescription antidepressant medication, the most commonly prescribed are selective serotonin reuptake inhibitors (SSRIs). Outcomes are extremely successful when involving therapy.

Next steps 

If you are experiencing SAD symptoms, seek guidance from a medical professional. It is important to determine whether there are any other underlying medical conditions causing similar symptoms. SAD can also be misdiagnosed and mistreated in the presence of hypothyroidism, hypoglycemia, infectious mononucleosis, and other viral infections. A clinical mental health professional should be consulted so a proper diagnosis, treatment and therapy options can be discussed. With the right treatment, SAD is an extremely manageable condition.

If you feel your depression is severe or if you are experiencing suicidal thoughts, consult a doctor immediately, seek help at the closest emergency room and/or contact the National Suicide Prevention Lifeline 24/7 (800-273-TALK (8255).