Seasonal affective disorder is not considered to be a unique diagnostic entity in itself, but rather a sub-type specifier used to describe temporal variations in recurrent major depressive or bipolar disorders over at least a 2-year period.
Most commonly presents with onset of depression in the autumn or winter, and full remission of symptoms in the spring or summer.
Atypical vegetative symptoms of depression are common, such as hypersomnia, hyperphagia, and weight gain.
Assessment is based on self-report, clinical interview, and behavioural observation.
Light therapy, selective serotonin-reuptake inhibitors, and serotonin-noradrenaline reuptake inhibitors, either alone or in combination, are considered the initial treatment options.
Longer-term clinical management and monitoring are typically required. Light therapy and/or bupropion (extended release) may be used as prophylactic therapy.
All patients must meet the diagnostic criteria for recurrent major depression or bipolar mood disorder. Seasonal affective disorder (SAD) is then a sub-type specifier used to describe temporal variations of these disorders. As such, SAD is not considered a stand-alone diagnosis or comorbid condition to recurrent major depression or bipolar disorder. Common presentations include the initiation or worsening of depressive symptoms during the autumn or winter months, and full remission during the spring or summer months, or hypo-manic or manic symptoms presenting during spring or summer months.
History and exam
Key diagnostic factors
- presence of risk factors
- ≥2-year period of seasonally related changes in mood
- autumn or winter depression
- spring or summer symptom remission
- atypical depressive symptoms
- vegetative depressive symptoms
- spring or summer manic or hypo-manic symptoms
- spring or summer depression
- manic/hypomanic symptoms
Other diagnostic factors
- somatic symptoms
- behavioural withdrawal
- functional impairments
- excessive alcohol use
- increased systolic blood pressure
- exposure to diminished light during winter and increased light during summer
- residing at a northern latitude
- family history of seasonal affective disorder (SAD)
- female sex
- age 20 to 30 years
- psychological factors (e.g., high neuroticism)
- psychiatric comorbidity (e.g., anxiety, ADHD, premenstrual dysphoric disorders)
- alcohol use
1st investigations to order
- clinical examination
Investigations to consider
- blood metabolic panel
- serum thyroid-stimulating hormone
- toxicology screen (urine and blood)
SAD with recurrent, unipolar depressive disorder
SAD with bipolar mood disorder
prevention of SAD with unipolar mood disorder
prevention of SAD with bipolar mood disorder
- Major depressive disorder, single and recurrent episodes
- Bipolar I and II disorders
- Persistent depressive disorder
- Depression in adults: treatment and management
- Clinical guidelines for the management of major depressive disorder in adults
Bipolar disorder: what is it?
Bipolar disorder: what medicines work?More Patient leaflets
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