Risk factors and treatment approaches to seasonal affective disorder: a review

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Summary

This review outlines the multifactorial causes of Seasonal Affective Disorder—including day length, circadian disruption, and neurotransmitter dysregulation—and compares treatment efficacy across bright light therapy, pharmacotherapy, and cognitive-behavioural therapy. For lighting designers and healthcare practitioners, the findings reinforce the importance of bright light exposure as a primary, safe intervention for SAD, particularly in high-latitude environments.

Key Findings

SAD affects 1–2% of the general population globally, but prevalence rises to 10–20% in regions more than 30 degrees from the equator.
A subsyndromal form (S-SAD or 'winter blues') exists and is more common than full SAD.
Circadian rhythm imbalances and dysregulation of serotonin, dopamine, and norepinephrine are identified as primary neurochemical risk factors.
Bright light therapy is identified as an effective first-line treatment, targeting circadian rhythm correction.
Cognitive-behavioural therapy (CBT) is noted as an effective adjunct or alternative, addressing maladaptive stress and anxiety responses associated with SAD.

Categories

Seasonal Affective Disorder: Directly reviews SAD prevalence, risk factors, and treatment approaches including light therapy.

Mood & Mental Wellness: Covers neurochemical and circadian mechanisms underlying SAD, linking to broader depression and mood regulation.

Sleep & Circadian Health: Identifies circadian rhythm imbalances as a key risk factor for SAD and discusses light therapy as a corrective intervention.