Maintenance therapy with an anti-manic agent, especially in BD I, is indicated for at least 2–4 weeks before initiation of BLT and during treatment (Yatham et al. 2018). Continuation of stable dosed antidepressant with anti-manic agent is reasonable (Sit et al. 2018; Yatham et al. 2018). Receive treatment guidance and mood monitoring from a trained clinician. Light therapy is contraindicated for the patient with current or recent mania, hypomania or rapid cycling.
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Positioning and Selecting Your Light Box. Figure 3. |
Select a bright, white, UV-filtered light, 5,000 to 10,000 lux at a distance of 30–33 cm (12–13 inches) from the eyes. Utilise devices with an established record of ophthalmic safety (Gallin et al. 1995; Brouwer et al. 2017). The dimension of the ideal unit measures a minimum of 30 cm (12 inches) in height by 36 cm (14 inches) in length and is optimally placed on a desk stand to deliver illumination from above. The unit should produce diffuse (low-glare) lighting across a broad visual field. Avoid directly staring at the unit to mitigate eye discomfort but ensure light from device illuminates the visual field. Daily use of the light at the same time of day is strongly encouraged to gain the full benefit of treatment.
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Timing and Dosing Schedule. |
Begin with 15 min/day of light therapy. The session can be administered either in the morning (shortly after waking, between 7:00 AM and 9:00 AM) or at midday (between 12:00 PM and 2:30 PM), depending on patient preference and clinical recommendations. Increase by 15 min every week to a maximum of 45–60 min/day (by week 4) OR until mood symptoms have completely remitted and patient’s functioning is restored. Expect clinical remission by four to six weeks of treatment (Sit et al. 2018; Lam et al. 2021). For non-responders, move the timing of light to the morning within minutes after awakening (Sit et al. 2018; Sit and Haigh 2019). Morning light can provide a higher response compared to other times of day (Terman et al. 1998).
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Adverse Effects and Safety Monitoring. |
Headache, eye strain, agitation, nausea, sleep disturbance, and menstrual disturbances are potential side effects of light therapy. Suicidal ideation and manic switch are infrequent adverse effects of light therapy (Sit and Haigh 2019; Lam et al. 2021; Geoffroy et al. 2025). In addition to clinician monitoring, consider utilising self-reported measures to assess patient centred outcomes (Young et al. 1978; Sit et al. 2018; Sit and Haigh 2019; Pulido et al. 2025). No ocular disorders were observed in a five-year study (Gallin et al. 1995; Brouwer et al. 2017). In rare instances of worsening depression, hypomanic induction, suicidal ideation, or mood cycles in association with light treatment, patients are advised to reduce the light dose or stop using the light box for a few days and contact their clinician for proper guidance (Terman and Terman 2005; Geoffroy et al. 2025). On weekends, holidays or off hours, go to the nearest urgent care clinic, crisis unit or emergency room for immediate medical attention.
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Continuation of Treatment. |
We expect continued improvement after 6 weeks of treatment (Sit et al. 2018)(see dose response relationship). Given that patients with BD who stop maintenance treatment with antidepressants after one year have 2x the risk for relapse compared to patients who continue treatment (70% vs 36%), certain remitted patients may prefer to continue bright light therapy to prevent recurrence.
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Lifestyle Management. |
Sleep disturbance is associated with residual mood symptoms, recurrent depressive episode and suicide ideation (Esaki et al. 2021a). Young to mid-aged outpatients with BD (≤ 44 years old) are observed to have reduced sleep efficiency, prolonged latency to sleep-onset and increased duration of wake after sleep onset in association with evening white light illumination (Esaki et al. 2021a). Given this evidence, quantify the amount and sources of daily light exposure and explore ways to reduce the exposure to evening light. Reduced physical activity (Melo et al. 2016), delayed sleep phase (Takaesu et al. 2018) and later timing of circadian rhythm activity (Esaki et al. 2021a) are predictors of bipolar depressive episode relapse. In contrast, increased daytime light exposure (Esaki et al. 2019) and increased circadian rhythm activity with robust circadian amplitude are protective factors and associated with a reduction in bipolar depressive symptoms (Esaki et al. 2019) and decreased risk for bipolar mood relapse (Esaki et al. 2021a). To stay well and avoid recurrent depression, encourage patients to engage in regular exercise, meals, social contact, and outdoors activity, practice healthy sleep habits and avoid excessive delays in bedtime.
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