Approach

The primary goals of acute treatment are to:

  • Reduce symptom severity

  • Restore functional capacity.

The treatment approach should consider:

  • Past treatment history

  • Patient preference

  • Comorbid disorders

  • Treatment availability.

A referral to a psychiatrist or mental health professional may be required in patients with:

  • An inadequate response to initial treatment

  • More severe mood symptoms

  • Complicated comorbid conditions.

Most seasonal affective disorder (SAD) treatment studies have examined the use of prescribed daily light therapy and antidepressants.[25] Few treatment outcome studies have extended beyond an 8-week period, thereby limiting their generalisability to clinical practice.[25] Given the recurrent nature of SAD, longer-term monitoring and maintenance treatment are highly recommended.[54]

Sub-syndromal symptoms

Patients who present with sub-syndromal SAD should be assessed further to establish a lifetime history of seasonal changes in mood. Although patients may not meet criteria for a major depressive disorder, they may still experience significant functional impairment.[55] No particular treatment is indicated for sub-syndromal clinical presentations. However, such patients would be likely to respond to evidence-based light therapy and antidepressants.[56][57]​ These may be considered particularly if the patient has significant functional impairment. Sub-syndromal depressive symptoms may also be managed through lifestyle changes, such as increasing physical activity levels, regulating sleep patterns, minimising screen exposure before bedtime, increasing exposure to natural light throughout the day, and staying engaged with healthy social supports and meaningful activities.[6][58]

Patients can be encouraged to monitor the intensity, frequency, and duration of seasonal mood symptoms, with particular emphasis on recognising atypical depressive symptoms in the autumn or winter and potential manic or hypomanic symptoms in the spring or summer. Patients are encouraged to learn more about the nature and treatment of SAD through available recommended websites. University of British Columbia: seasonal affective disorder information page Opens in new window Mind: seasonal affective disorder Opens in new window​ Follow-up evaluations or telephone checks are recommended within 2-4 weeks to re-assess patient status. If functional impairments become more severe, therapy with either light or antidepressants may be started.

Recurrent, unipolar depressive disorder with SAD: initial therapy

Initial treatment is with antidepressants or light therapy. Providing education about the evidence for the various treatment options and availability can assist patients in making a choice over preferred interventions. Few studies have directly compared light therapy versus antidepressants, although there is limited evidence that light therapy and fluoxetine are equally efficacious.[59][60]

Light therapy

Light therapy may be preferable to pharmacotherapy, due to its quicker response and fewer adverse effects. Self-reported depression scores have been found to decline after 1 hour of light therapy exposure.[61] Bright-light therapy should be conducted in an evidence-based manner for the treatment to be effective, and patients should obtain a lightbox that meets evidence-based guidelines from a reputable vendor.[25]​​ Patient compliance with the light therapy regimen can be problematic.[62] Relative contraindications for light therapy include:[25]

  • Retinal disease

  • Macular degeneration

  • Current use of photosynthesising drugs.

Meta-analyses of randomised controlled trials for light therapy in people with recurrent unipolar depression have yielded moderate to large effect sizes.[63][64]​ Consensus guidelines conclude that light therapy has limited positive evidence from controlled trials.[65][66]​ Clinical improvement in symptoms may be observed within 1-3 weeks of consistent administration. If light therapy is discontinued, symptoms may relapse within 1-3 weeks.[54] The optimal dosing of light therapy is at least 5000 lux/day, which may involve 2 hours at 2500 lux or 30 minutes of 10,000 lux intensity, during the early morning hours or on rising. General practice guidelines for administration include the following:[25]​​[65][67]

  • Apply 10,000 lux white fluorescent light for 30 minutes/day during early morning or on rising

  • Stay awake with eyes open; may engage in light activity, such as reading

  • Determine response after 2-3 weeks of consistent administration

  • At the point of symptom remission, individually tailor the dose intensity and/or duration for the remainder of the winter season (e.g., reduce to 15 minutes/day)

  • Continue therapy until the time of usual symptom remission in the spring or summer

  • Re-initiate light therapy in early autumn to offset relapse.

Antidepressant therapy

Although few randomised, controlled trials studying antidepressant therapy for SAD are available, selective serotonin-reuptake inhibitors (SSRIs), especially fluoxetine and sertraline, have demonstrated efficacy.[59][68][69]​ In two small randomised trials, fluoxetine had comparable response rates to light therapy.[70] Other SSRIs used to treat major depressive disorders are also likely to be useful in the treatment of SAD, including citalopram, paroxetine, and escitalopram.[25][71][72]​ Fluoxetine has a long half-life and therefore is least likely to cause withdrawal symptoms, but is more stimulating and may require a slower titration for some patients. Paroxetine has the shortest half-life and is most likely to cause withdrawal symptoms. A National Institute for Health and Care Excellence (NICE) guideline found some evidence for antidepressants when used as a prophylactic treatment for seasonal depressive symptoms before they start, whereas evidence was limited for the use of antidepressants once seasonal symptoms have started.[65]

Serotonin-noradrenaline reuptake inhibitors (SNRIs), such as duloxetine, have a similar adverse-effect profile to SSRIs and are also likely to be efficacious. However, data are limited.[73]

Antidepressants, including SSRIs, SNRIs, and bupropion, increase the risk of suicidality in young adults (as well as children and adolescents, who are beyond the scope of this topic) with major depressive or other psychiatric disorders, especially during the first months of treatment with antidepressants.[74]​ Most antidepressant adverse effects are time-limited during dose titration and should be discussed in advance with patients and monitored closely to ensure compliance. Other than considering the evidence for efficacy, the choice of antidepressant depends on:

  • Previous treatment response

  • Availability

  • Adverse effects

  • Risk of withdrawal symptoms

  • Ease of titration.

Abruptly discontinuing or rapidly tapering antidepressants can increase the risk of withdrawal symptoms, such as dizziness, irritability, anxiety, restlessness, sweating, nausea, palpitations, and headaches.[65][75]​​ To minimise these risks, a gradual and proportionate tapering schedule with close monitoring is recommended.[65][75]​​ Drugs with a shorter half-life (e.g., paroxetine) should be tapered more slowly. This process may take several months, progressing at a rate that is comfortable for the patient.[76]​ Withdrawal symptoms can range from mild and transient to prolonged and severe. Close monitoring is necessary to ensure that any withdrawal symptoms do not in fact represent a return of SAD symptoms.[65][75]

Combined light therapy and antidepressant therapy can be initiated in many SAD patients, although there is no evidence for combining these treatments for non-seasonal depression.[65] Combined light therapy with duloxetine demonstrated improved antidepressant response and remission compared with an exercise-duloxetine combination.[77] More severe and functionally impairing depressive symptoms may warrant combined treatments. Depressive symptoms that do not fully remit during the spring or summer months may also warrant combined treatments.

Bipolar mood disorder with SAD: initial therapy

All patients with autumn- or winter-onset depression should be screened for spring or summer hypomania or mania symptoms. An estimated 25% of people with SAD may present with a bipolar disorder.[9] SAD appears to show an earlier onset among those with bipolar II disorder as opposed to those with major depression or bipolar I disorder.[10]​ Initiation of a mood-stabilising drug is indicated, and this can be used in conjunction with light therapy when mood is depressed. Early monitoring of response to light therapy is required, as light exposure may induce manic symptoms in some populations, although this is uncommon.[66]

Lithium, valproic acid, and some atypical antipsychotics are generally considered first-line mood stabilisers.

Valproic acid (and its derivatives) must not be used in female patients of child-bearing potential unless other options are unsuitable, there is a pregnancy prevention programme in place, and certain conditions are met. Precautionary measures may also be required in male patients owing to a potential risk that use in the three months leading up to conception may increase the likelihood of neurodevelopmental disorders in their children. Regulations and precautionary measures for female and male patients may vary between countries, with some countries taking a more heightened precautionary stance, and you should consult your local guidance for more information.

Alternative first-line treatments may be considered in consultation with a consultant, depending on the clinical presentation. Choice of treatment is based on features of the bipolar illness and weighing the wide range of immediate adverse effects and long-term risks. Patients taking lithium require routine serum blood level testing to monitor therapeutic blood levels and to offset toxicity risk. See Bipolar disorder in adults.

Comorbid anxiety disorders

Anxiety disorders, such as panic disorder, generalised anxiety disorder, and social anxiety disorder, are equally prevalent in non-seasonal major depression and SAD.[11] There are no clinical trials assessing the efficacy of light therapy or antidepressant pharmacotherapy in the management of SAD with comorbid anxiety. Given the few contraindications for light therapy and the established research base for SSRIs and SNRIs, both treatments, either alone or in combination, would be indicated.

Comorbid premenstrual dysphoric disorder

SSRIs and SNRIs have been shown to be helpful in treating premenstrual dysphoric disorder and SAD separately.[73][78]​​​​[79]​ The prevalence of premenstrual dysphoric disorder is higher among patients with SAD than in the general population.[13][80]​​ Therefore, although there are no data to guide comorbid treatment, SSRIs and SNRIs are frequently used for these patients. Light therapy is an alternative first-line therapy. Oral contraceptives are also an effective treatment for premenstrual dysphoric symptoms, but they are unstudied in SAD.[81]

Adjunctive therapy in all patients

Clinical management can be complicated by sedentary behaviour and social disengagement. Thus, adjunctive use of low-impact physical activity and/or a referral for evidence-based cognitive behavioural therapy (CBT) may be indicated in some cases.[58][82]​​​ Minimising screen exposure before bedtime, maintaining a consistent sleep schedule, and increasing exposure to natural light throughout the day may also improve mood symptoms.[6]

CBT is an effective treatment for depression and anxiety disorders. It can be a useful adjunct in the management of SAD, especially under conditions of increasing impairment and comorbidity.[82] CBT is a skills-based approach designed to modify thoughts, behaviours, and environmental contingencies that are maintaining or exacerbating symptoms and impairments. Goals of treatment involve learning strategies to behaviourally manage depressive symptoms, reduce avoidance behaviour, and gradually improve and regain function over time. In one head-to-head comparison study, CBT and light therapy yielded similar positive outcomes in the acute treatment of SAD.[83] However, longer-term follow-up noted that CBT showed longer-lasting improvements on measures of depressive symptoms than light therapy.[84] Combination therapy of CBT and light therapy has shown to improve symptom outcomes in comparison to light therapy alone.[65] The referring physician and mental health professional should maintain routine collaboration.

Prophylactic therapy

Bupropion (extended-release) is the only drug that is approved in some countries for prevention of SAD.[6][85]​​​ Guidance suggests that treating SAD in a prophylactic manner is generally more effective than using antidepressants to treat SAD symptoms during the active phase.[65] Treatment begins in early autumn and should be continued through winter.[85] Bupropion is unstudied as an acute treatment for mid-episode seasonal depression. Relapse rates for effectively treated seasonal depression may be reduced through initiation of antidepressant therapy.[76]

Bright-light therapy can also be used as a prophylactic measure. Outcome trials are very limited, but do show some support for using bright light therapy to prevent symptoms.[86] The risks and benefits of considering prophylactic treatments across time should be discussed with the patient.[54]

Non-compliance with treatment

Management of non-compliance with a treatment regimen includes normalising difficulties with maintaining light therapy and/or pharmacotherapy treatment, and identifying barriers to care delivery. Practical problem-solving strategies and shared decision-making can be used to help patients. Brief telephone check-ins and involvement of family members may encourage adherence to treatment. Consultation with mental health professionals for additional advice or referral may be required. Patients may benefit from online education materials. University of British Columbia: seasonal affective disorder information page Opens in new window Mind: seasonal affective disorder Opens in new window

Use of this content is subject to our disclaimer