Seasonal Affective Disorder (SAD)


Published: 07 July 2018

When you think of winter, you may at first associate it with the flu, colds or respiratory complications such as pneumonia. However, in the cooler months, seasonal affective disorder (SAD) may be often overlooked as a simple case of the 'winter blues' (Healthdirect 2020).

SAD is a mood disorder that takes trend in the form of a seasonal depression each year, with the condition generally concluding in spring or summer (the warmer seasons) (Healthdirect 2020). However, some people experience SAD through spring and summer too (Mayo Clinic 2017).

Signs of Seasonal Affective Disorder

Autumn to Winter

Some of the SAD signs to watch for in autumn and winter include:

  • Tiredness
  • Excessive sleeping
  • Increased weight
  • Increased appetite
  • Craving carbohydrates.

(Healthdirect 2020; Mayo Clinic 2017)

Spring to Summer

Some of the SAD signs to watch for in spring and summer include:

  • Agitation
  • Anxiety
  • Low appetite
  • Weight loss
  • Insomnia.

(Mayo Clinic 2017)

Additional Seasonal Affective Disorder Symptoms

  • Feeling depressed the majority of the day on most days
  • Lack of enjoyment for activities that are usually enjoyable
  • Poor concentration
  • Depressed, negative thoughts.

(Mayo Clinic 2017)

Who Experiences Seasonal Affective Disorder?

Nussbaumer et al. (2015) state that many people living in northern latitudes commonly experience a ‘winter blues’. However, for some people, these 'winter blues' eventuate into clinical depression.

Strikingly, up to 75% of people with SAD are female (Kaminski-Hartenthaler et al. 2015).

For most (up to two in three) people with Winter-SAD, they can expect to experience it every year (Fornasier et al. 2015; Nussbaumer et al. 2015). Forneris et al. (2015) acknowledge that one benefit of this is that its predictability may help to implement prevention or intervention strategies.

Can A Change of Scenery Help?

According to research by Forneris et al. (2015), ‘the prevalence of SAD ranges from 1.5% to 9%', with the variance due to a difference in geographical latitude.

Living further away from the equator appears to increase the risk of SAD. This is quite possibly due to the limited sunlight in Winter months and longer Summer days (Mayo Clinic 2017).

Preventing Seasonal Affective Disorder

Unfortunately, there is currently insufficient evidence to conclude whether psychological therapy is effective in preventing SAD (Forneris et al. 2015).

Similarly, there is not enough high-quality research (e.g. RCTs) to compare the effectiveness of psychological interventions (e.g. CBT, behaviour therapy) to other treatments such as light therapy, melatonin treatment, agomelatine, lifestyle modifications, placebos and second-generation antidepressants (SGAs) (Fornasier et al. 2015).

What is Light Therapy?

woman undergoing light therapy whilst reading a book

Light therapy is the act of exposing a person to light to simulate different times of day in the hopes of manipulating the body clock, and in turn, other body functions (Cunnington 2015).

Examples of light therapy include bright white light and dawn simulation (Terman, 2005 cited in Nussbaumer et al. 2015).

As there is evidence to suggest disruptions to sleep and circadian rhythms can contribute to mood disorders (Srinivasan et al. 2015), the idea behind using light therapy to treat SAD is that it might manipulate brain chemicals to improve mood (Mayo Clinic 2016).

According to a systematic review by Nussbaumer et al. (2015), only limited evidence was found in support of light therapy as an effective tool in preventing SAD.

Can Pharmacological Supplements Prevent or Treat SAD?

According to Srinivasan et al. (2012), disruptions to sleep and circadian rhythms, such as ‘malfunctioning of the SCN–pineal–melatonin link’, can contribute to mood disorders such as SAD

Melatonin is essential for the control of mood and behaviour’, and it is involved in rhythm-regulation and sleep regulation (Srinivasan et al. 2012).

Agomelatine is a ‘melatonergic antidepressant’ that Srinivasan et al. state is also effective for treating mood disorders.

However, Kaminski-Hartenthaler et al. (2015) found in their systematic review that there is not enough evidence to determine whether or not melatonin or agomelatine are able to prevent SAD or improve outcomes for clients. Thereby, more high quality RCTs are necessary in order to investigate their effects, particularly in comparison to other SAD therapies (e.g. light therapy, psychological therapy) (Kaminski-Hartenthaler et al. 2015).

It is proposed that other second-generation antidepressants can be used in the treatment of autumn/winter SAD and may help to prevent depression (Gartlehner et al. 2015). However, research by Gartlehner et al. (2015) and Morgan et al. (2015) state that to confidently conclude SGAs should be used in preventing SAD, more high-quality research on this topic would be needed.

Seeking Help

Better Health Channel (2018) reinforces that seasonal affective disorder is uncommon in Australia and mostly occurs in colder-climate areas of the Northern Hemisphere that experience shorter days with longer durations of darkness. However, if you are experiencing any extended feelings of sadness, Better Health Channel recommends the following resources to reach out to:

  • Call 000
  • See your GP
  • Access a mental health team and/or psychologist (e.g. at a community health centre)
  • beyondblue Support Service Tel. 1300 22 4636
  • Lifeline Tel. 13 11 14
  • Kids Helpline Tel. 1800 55 1800
  • SuicideLine Tel. 1300 651 251
  • SANE Australia Helpline Tel. 1800 187 263
  • Australian Psychological Society – Find a psychologist service Tel. 1800 333 497 (outside Melbourne) or (03) 8662 3300 (in Melbourne)
  • Mind Australia Tel. 1300 AT MIND.



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Madeline Gilkes View profile
Madeline Gilkes, CDE, RN, is a Fellow of the Australasian Society of Lifestyle Medicine. She focused her Master of Healthcare Leadership research project on health coaching for long-term weight loss in obese adults. Madeline has found a passion for preventative nursing. She has transitioned from leadership roles (CNS Gerontology & Education, Clinical Facilitator) in the acute/hospital setting to education management and primary healthcare. Madeline’s vision is to implement lifestyle medicine to prevent and treat chronic conditions. Her research proposal for her PhD involves Lifestyle Medicine for Type 2 Diabetes Mellitus. Madeline is a Credentialled Diabetes Educator (CDE) and primarily works in the academic role of Head of Nursing. Madeline’s philosophy focuses on using humanistic management, adult learning theories/evidence and self-efficacy theories and interventions to promote positive learning environments. In addition to her Master of Healthcare Leadership, Madeline has a Graduate Certificate in Diabetes Education & Management, Graduate Certificate in Adult & Vocational Education, Graduate Certificate of Aged Care Nursing, and a Bachelor of Nursing. She is working towards her PhD.