Bright light therapy and chronotherapy for winter depression (MEQ)

(i) Seasonal pattern and light as first-line. DSM-style seasonal pattern: regular temporal relationship between major depressive episodes and a particular time of year (here winter) across successive years, with full remissions at other times. Her reverse-vegetative features match the classic winter SAD phenotype described since Rosenthal. Meta-analyses (Golden; Pjrek) support bright light therapy efficacy for SAD; it is an appropriate first-line non-drug option given preference and moderate severity without active plan.[1][2][6]

(ii) Protocol. UV-filtered commercial light box delivering approximately 10,000 lux at the manufacturer’s prescribed distance; about 30 minutes daily shortly after habitual waking; eyes open facing toward the box while reading/working (not staring); continue through the symptomatic winter months; early review for tolerability then efficacy at 1–3 weeks. Avoid late-evening sessions.[3]

(iii) Versus fluoxetine. Can-SAD found light therapy and fluoxetine 20 mg oral daily comparably effective for winter SAD, with light often showing earlier response onset and a different AE profile. Offer either; combine if incomplete response or strong dual preference after discussion.[4]

(iv) Safety. Common: headache, eye strain, nausea, irritability, insomnia if mistimed. Hard stops: emergent hypomania/mania (stop/reduce light, reassess bipolar spectrum); ocular disease or severe photophobia (pause, ophthalmic review); photosensitising drugs without review. Always maintain suicide risk assessment — seasonality is not reassurance.[3]

(v) Escalation. If severity rises (active SI, psychosis, poor intake), escalate care intensity; do not rely on light alone. Specialist chronotherapy packages (wake therapy with light ± medication) are for structured settings when rapid response is needed. Incomplete winter response after adequate BLT: optimise timing/dose, add SSRI, consider CBT-SAD skills for durability.[5][7]