Is it the holiday blues, or seasonal affective disorder?


Seasonal affective disorder, or SAD, is a type of depression that follows a seasonal pattern, typically occurring during the fall and winter months when daylight hours decrease. Also known as the “winter blues” or “winter depression,” SAD is characterized by a recurrent onset of depressive symptoms that remit in the spring and summer. While it is less common, some individuals may experience SAD during the warmer months.

The exact cause of SAD is not fully understood, but it is believed to be linked to the changes in exposure to natural light that occur with the seasons. For many, it feels like having their own portable black cloud. Reduced sunlight exposure can disrupt the body’s internal clock (circadian rhythms) and lead to alterations in neurotransmitter levels, such as serotonin and melatonin, which play crucial roles in regulating mood and sleep patterns.

What are the warning signs of seasonal affective disorder?

  • Persistent low mood
  • Loss of interest or pleasure in activities you once enjoyed
  • Decreased ability to focus or concentrate
  • Irritability and anxiety
  • Difficulty concentrating
  • Trouble sleeping
  • Fatigue, or low energy level
  • Feelings of guilt and hopelessness
  • Changes in appetite, and fluctuations in weight

Why do people get seasonal affective disorder?

The prevalence of SAD varies based on geographic location and a number of factors that can make certain individuals more vulnerable to developing the disorder. These include:

  • Age: The likelihood of experiencing SAD decreases with age, with the highest prevalence among individuals aged 18-30
  • Gender: Women are more susceptible to SAD compared to men
  • Location: SAD rates are higher in regions with reduced sunlight and longer winter nights. The risk increases as one moves farther from the equator
  • Family history: Genetics can contribute to SAD. Individuals with a family history of SAD or other depressive disorders have a higher risk of developing the condition themselves

How is SAD diagnosed?

Diagnosing seasonal affective disorder requires a comprehensive assessment involving symptoms, medical history, and exclusion of other potential causes of depression. The seasonal pattern assessment questionnaire (SPAQ) is a frequently utilized diagnostic tool that evaluates the seasonal fluctuations in mood and behavior. To be diagnosed with SAD, depressive episodes must occur during specific seasons for at least two consecutive years.

The two faces of SAD

Fall-onset: Often referred to as “winter depression”, its symptoms tend to arise in late fall to early winter and ease during the warmer months.

Spring-onset: While SAD is commonly associated with the winter months, some individuals may experience a form of “reverse SAD”, also called “summer depression”, with symptoms emerging during the warmer season. This variant is less prevalent but underscores the complex relationship between light exposure and mood regulation.

Treatment options

Light therapy, or phototherapy, is a widely recognized and effective treatment for SAD. It involves exposure to bright light that mimics natural sunlight, typically for 20-60 minutes each day. Light therapy is thought to help regulate circadian rhythms and boost serotonin levels, alleviating symptoms of depression. In more severe cases, psychotherapy or medication, such as selective serotonin reuptake inhibitors (SSRIs), may be recommended.


  • The further you live north or south of the equator, the more common SAD becomes
  • Interestingly, SAD does not occur in the tropics
  • The seasonality of the symptoms helps make the diagnosis
  • As much as 90% of people with SAD experience depressive symptoms during the fall and winter
  • Just about 10% have these episodes occur during the spring and summer
  • Nearly 20% of people affected by SAD suffer from bipolar disorder
  • Cravings for foods high in carbohydrates and sugar are triggered by decreased levels of serotonin, a neurotransmitter associated with mood regulation and appetite
Beyond these conventional treatments, lifestyle modifications can also play a significant role in coping with SAD. Regular exercise, especially outdoor activities, exposure to natural light to stimulate the production of vitamin D, and maintain a consistent sleep schedule are essential components of a comprehensive approach to alleviating symptoms.


Seasonal affective disorder is a recurrent form of depression linked to seasonal changes, most commonly occurring in the fall and winter months. With its impact on mood, energy levels, and daily functioning, SAD is a significant mental health concern that can be effectively managed through a combination of light therapy, lifestyle adjustments, and, in some cases, psychotherapy or medication. Increasing awareness and fostering understanding around SAD contribute to a more supportive environment for those navigating the challenges of this seasonal condition.