Bright-light therapy

1. Introduction

Version followed: bright-light therapy as described by the ISBD Chronobiology and Chronotherapy Task Force recommendations (Geoffroy et al., 2025, full text), the CANMAT 2023 depression guideline update (Lam et al., 2024, full text), the UBC Seasonal Affective Disorder clinic pages (Lam and colleagues), NHS guidance (reviewed December 2025) and the Rohan et al. (2015) trial protocol; CBT-SAD as delivered in Rohan et al. (2015) and structured in Rohan's therapist guide Coping with the Seasons (Oxford University Press, Treatments That Work).

Source note (October 2026): treatment lines are taken from the full text of the CANMAT 2023 update and the ISBD 2025 recommendations; CBT-SAD structure from Rohan et al. (2015) and the Oxford Academic chapter pages of Rohan's therapist guide. Still [uncertain]: whether the final NICE NG222 guideline makes any recommendation on light therapy, and any SLTBR clinical or device guidance.

Bright-light therapy (BLT) means sitting daily in front of a device that gives bright, diffuse, UV-filtered white light, usually a light box, to treat depression with a seasonal (winter) pattern and, as an adjunct, some non-seasonal and bipolar depressions [source: ISBD 2025 full text; UBC light devices page; NHS]. Sources describe it as a chronobiological treatment: light exposure at a time of day that guidelines specify, acting on the body clock and mood [source: ISBD 2025]. CANMAT 2023 keeps light therapy as a first-line monotherapy for seasonal (winter) depression (Level 1 evidence); for non-seasonal major depression it places it second-line for mild severity and as an adjunct to medication for moderate severity, citing meta-analyses with larger effects when light is combined with antidepressants [source: CANMAT 2023, Lam et al. 2024].

This is not a psychotherapy. Guidelines specify the light intensity, the session duration, the time of day and how these are adjusted. This guide deliberately gives none of those numbers: the regimen is set, and changed, by the prescriber, the physician supervising treatment or a sleep specialist. The psychotherapist's role is recognition, referral, psychoeducation, support for informed decisions and routines, monitoring and passing on warning signs, and offering psychological treatment for seasonal depression (CBT-SAD) alongside or instead of light, as the client and medical team decide [synthesis, based on the sources above].

Who delivers it and regulatory status (checked October 2026):

United States: light boxes are not approved or regulated by the FDA specifically for seasonal affective disorder; they are sold without prescription and insurance usually does not cover them (as of October 2026 per a Mayo Clinic Health Information Library page updated January 2025) [source: Mayo Clinic via Koç University Hospital]. The UBC page advises a UL safety approval for US use [source: UBC light devices].
Canada: the UBC SAD clinic states light devices are not well regulated in Canada and advises CSA-approved devices with a UV filter that have been tested in scientifically valid studies [source: UBC light devices].
United Kingdom: NHS says light therapy is not usually available on the NHS because there is not enough evidence on whether it works, although many people report it helps; it advises speaking to a GP first and choosing a lamp with no UV and a UKCA or CE mark (as of October 2026 per NHS page reviewed 17 December 2025) [source: NHS SAD treatment].
NICE: the final NICE depression guideline (NG222) recommendation wording on light therapy is not reproduced here [uncertain]. A 2018 consultation-stage evidence appendix for the guideline (Appendix L, GRADE profiles) lists evidence profiles for bright light therapy and for non-light therapies for depression with a seasonal pattern, so NICE reviewed this evidence; the appendix itself contains no recommendation [source: NICE NG222 addendum appendix 17]. NHS patient guidance says light therapy is not usually available on the NHS (above). Check the NICE guideline directly before quoting a NICE position.
Society for Light Treatment and Biological Rhythms (SLTBR): its website describes it as an international scientific non-profit, founded in 1988, that brings together scientists and clinicians on the science and practical application of chronotherapy; its site gives no device, safety or practice guidance [source: SLTBR site]. No SLTBR clinical guidance is cited here [uncertain]. The UBC group lists a clinician's treatment manual on light and other chronotherapies (Lam and Tam, 2010; not reviewed here) [source: UBC clinician's guide page].
Supervision: all cited sources advise medical assessment before starting (see a doctor or GP; eye specialist if eye problems) rather than self-diagnosis and self-treatment [source: UBC light devices; NHS; Mayo].

2. Framework

Sources do not set out "phases" for the therapist; the sequence below arranges what they describe into a working pathway [synthesis].

Phase 1: Recognition and assessment (psychotherapist, 1–2 sessions within ongoing therapy). Goal: notice a recurring seasonal pattern and gather a clear history. NHS notes a diagnosis usually requires depressive symptoms at the same time of year for at least two years [source: NHS]. UBC warns that depressive symptoms can have other medical causes, so self-diagnosis is not recommended [source: UBC light devices]; the Rohan trial screened out hypothyroidism and bipolar disorder [source: Rohan et al. 2015]. Move on when: a seasonal pattern is plausible and the client is interested in medical assessment.

Phase 2: Medical evaluation and decision (prescriber, GP, psychiatrist or sleep specialist; eye specialist where indicated). Goal: confirm the diagnosis, exclude contraindications (bipolar status: acute or recent mania or hypomania, mixed symptoms, rapid cycling; retinal disease and other eye conditions, light hypersensitivity or photophobia; photosensitising medicines), choose between light therapy, medication, psychotherapy or a combination, and set the regimen [source: ISBD 2025 full text; Mayo; NHS]. Move on when: the medical team has agreed a plan and the client has made an informed choice.

Phase 3: Initiation (medical team; therapist supports). In the Rohan trial a scripted instruction session covered device set-up and positioning, the rationale, instructions and possible side effects [source: Rohan et al. 2015]. ISBD describes the prescriber adapting the starting regimen where hypomania is a concern or response is partial [source: ISBD 2025 abstract].

Phase 4: Acute course with monitoring (several weeks). ISBD describes improvement typically within 1–2 weeks, with response or remission expected by 4–6 weeks in bipolar depression [source: ISBD 2025 abstract]. Side effects and mood are tracked (in the Rohan trial by weekly self-report diaries reviewed by the investigators, with adjustments phoned through) [source: Rohan et al. 2015]. ISBD stresses that daily sessions are critical and adherence needs active attention, that treatment guidance and mood monitoring should come from a trained clinician with regular follow-up and patient-centred outcome measures, and that daily assessment and rapid adjustment are easier in hospital than in outpatient settings [source: ISBD 2025 full text]. Move on when: response is judged by the treating clinician; non-response returns the client to Phase 2.

Phase 5: Maintenance and seasonal relapse prevention. NHS: many people need treatment every winter to stop symptoms returning [source: NHS]. ISBD: maintenance after remission may help prevent relapse, often at a reduced regimen, though its role in bipolar maintenance is not yet settled [source: ISBD 2025 abstract; Psychopharmacology Institute summary]. Decisions on continuing, reducing or stopping belong to the prescriber.

Parallel psychotherapy track: CBT-SAD. In Rohan et al. (2015), CBT-SAD was delivered in closed groups of 4–8, led by a doctoral psychologist with a co-therapist, as 12 sessions of 90 minutes twice weekly over 6 weeks, compressed so treatment ended before spring; it produced improvement comparable to light therapy over the acute phase [source: Rohan et al. 2015]. The therapist guide is Rohan KJ, Coping with the Seasons: A Cognitive-Behavioral Approach to Seasonal Affective Disorder. Therapist Guide (Oxford University Press, Treatments That Work series; online on Oxford Academic from September 2008, print 2009 per library catalogue); it runs from therapist background and group logistics through 12 group sessions to fidelity checklists [source: Oxford Academic chapter pages; SIU-BDU library catalogue table of contents]. Only chapter titles and short abstracts are drawn on, not the session text; a companion client workbook is [uncertain].

3. Guiding principles

Stay in your lane on the regimen. Never set, adjust or advise on light intensity, duration, timing, distance or stopping; route every such question to the prescriber or sleep specialist [synthesis, consistent with sources' advice to see a doctor first].
Medical assessment before light. Depressive symptoms can have medical causes and light can harm some people; encourage a GP or physician review rather than self-treatment [source: UBC light devices; NHS].
Bipolar status matters. ISBD lists acute mania, recent mania or hypomania, mixed symptoms and rapid cycling as contraindications; for bipolar I it indicates anti-manic treatment before and during light therapy, and for bipolar II it leaves mood-stabiliser cover to clinician discretion [source: ISBD 2025 full text; Mayo]. Practically: screen every client for bipolar history and tell the prescriber.
Eyes and light-sensitising medicines matter. ISBD lists retinal disease, photosensitising medicines (sulphonamides, chloroquine and St John's wort are named) and light hypersensitivity or photophobia as contraindications, and advises a comprehensive eye examination first for reduced vision, recent vision changes or past eye disease, with ophthalmologist input after laser eye surgery; Mayo adds glaucoma, cataracts and diabetic eye damage as reasons to see an eye specialist first [source: ISBD 2025 full text; Mayo]. Practically: ask, record and pass on.
Treat light as a medical device choice, not a lifestyle purchase. Devices vary in output and filtering; sources advise UV-filtered devices designed for SAD (not skin-treatment lamps), tested in studies, with recognised safety markings [source: UBC light devices; Mayo; NHS; Psychopharmacology Institute].
Adherence is the active ingredient you can influence. Sources describe it as requiring daily engagement and follow-up; your work is routine-building and problem-solving, never changing the prescription [source: Psychopharmacology Institute summary of ISBD; synthesis].
Measure, and share the measures. Patient-reported scales for depression, anxiety and mania are suggested to track progress and detect switching [source: Psychopharmacology Institute summary of ISBD]; CANMAT 2023 recommends a validated rating scale and measurement-based care to monitor response, tolerability and adherence [source: CANMAT 2023, Lam et al. 2024].
Psychotherapy is a real alternative, not just an add-on. CBT-SAD performed comparably to light therapy acutely; some people do better with light combined with antidepressants or talk therapy [source: Rohan et al. 2015; Mayo].
Respect client preference and access. For mild depression CANMAT 2023 notes that evidence-based psychotherapy and medication have similar efficacy, prefers a first-line psychotherapy where readily accessible, and lists patient preference, availability, cost and insurance coverage as factors in the choice; it recommends shared decision-making [source: CANMAT 2023, Lam et al. 2024]. Light boxes are often not reimbursed [source: Mayo; NHS]. Practically: explore cost and practicality openly.
Plan for the next winter. Seasonal depression recurs; build relapse-prevention plans before the season starts [source: NHS; Rohan et al. 2015].

4. Intervention inventory

Part A describes the treatment as guidelines and clinical sources publish it, at a descriptive level only, so you can explain it and spot problems. Part B is the psychotherapist's own work. No intensity, duration, distance or timing figures are given here: those are in the guidelines and are set by the prescriber or sleep specialist.

Part A. The treatment as delivered (descriptive)

A1. Bright-light therapy with a light box

Purpose: treat winter-pattern depression (first-line) and, as an adjunct or second-line option, non-seasonal depression; ISBD also covers bipolar depression [source: CANMAT 2023, Lam et al. 2024; ISBD 2025 abstract].
What happens (as sources describe): after medical review, the client uses a bright, white, UV-filtered light device each day, at a time of day the prescriber sets in line with guidelines [source: ISBD 2025 full text; Mayo]. ISBD describes a diffuse, low-glare unit on a desk stand, above eye level and angled slightly down; the eyes stay open but the person does not stare into it, and can read, eat, craft or watch TV during the session [source: ISBD 2025 full text; Mayo]. Guidelines specify the intensity, session length, timing and distance; NHS and Mayo say to follow the manufacturer's instructions and the clinician's plan [source: NHS; Mayo]. How treatment is started, built up and adjusted is the prescriber's decision [source: ISBD 2025 full text].
Side effects described: ISBD lists common, usually mild effects: headache, dizziness, sleep disturbance, eye strain, nausea and activation (agitation, anxiety, arousal), and reports no light-therapy-related eye disorders in a meta-analysis or a five-year follow-up [source: ISBD 2025 full text]. In the Rohan trial: headaches or migraines, waking too early, early-evening sleepiness and feeling overactive (one case reviewed by a psychiatrist and judged not to be hypomania); the investigators managed these by adjusting the regimen, and two participants could tolerate only a minimal one [source: Rohan et al. 2015]. Mayo flags manic symptoms in bipolar disorder and eye damage from UV (especially from skin-treatment lamps) [source: Mayo].
Watch for (therapist): headache, sleep shifts, agitation or 'too much energy', irritability, eye discomfort; pass each to the prescriber [synthesis].
Example language (illustrative): "Light therapy means using a special lamp every day, on a plan your doctor sets from the guidelines. While it's on you can read or eat; you just don't stare into it." [synthesis]

A2. Device choice and other formats

Purpose: help the client understand what the prescriber may recommend and avoid unsuitable products.
What sources say: choose a box made for SAD, not for skin conditions; it should filter out (nearly all) UV light; prefer a device tested in valid studies, from a reliable manufacturer, with CSA (Canada) or UL (US) approval, or UKCA or CE marking (UK) [source: UBC light devices; Mayo; NHS]. Larger desktop units are preferred because they depend less on exact positioning; small cheap devices are not recommended [source: UBC light devices]. Fluorescent light boxes have the most testing; LED devices, light visors and dawn simulators may help some people but have weaker evidence; narrow-band blue light is probably effective but less studied, with no evidence it beats white light and unknown long-term safety [source: UBC light devices]. ISBD recommends only UV-filtered devices for clinical use, names device variability as a barrier, and says blue-only light is not established as superior to bright white light [source: ISBD 2025 full text].
Watch for: clients buying cheap, unmarked or skin-treatment lamps, or starting without medical review; encourage a conversation with the prescriber before purchase [synthesis].
Example language (illustrative): "Before you buy anything, it's worth asking your doctor which kind of device they'd want you to use; the cheap ones online aren't all built for this." [synthesis]

A3. Light therapy in bipolar depression (ISBD 2025)

Purpose: an add-on to existing treatment (not a replacement) that the ISBD task force calls "likely an efficacious acute treatment for bipolar depression"; its maintenance role "awaits further investigation" [source: ISBD 2025 full text].
What sources say: protocols resemble those for unipolar depression; contraindications include acute or recent mania or hypomania, mixed symptoms and rapid cycling; anti-manic treatment is indicated before and during light therapy in bipolar I and left to clinician discretion in bipolar II; a trained clinician guides treatment and monitors mood with regular follow-up and patient-centred measures; if hypomanic symptoms appear, ISBD advises reducing or stopping treatment (the prescriber's decision); for manic switch, worsening depression or suicidal ideation it advises patients to cut back or stop the light, contact their clinician promptly and seek urgent care in a crisis [source: ISBD 2025 full text]. A 2020 meta-analysis listed by the UBC group found light therapy was not associated with an increased rate of mood switching in bipolar depression [source: UBC clinician's guide page]; the Psychopharmacology Institute summary reports switch rates appear lower than with antidepressants [source: Psychopharmacology Institute summary of ISBD].
Watch for (therapist): reduced need for sleep, pressured speech, racing thoughts, risk-taking, irritability, mixed features; contact the prescriber the same day [synthesis].
Example language (illustrative): "With bipolar disorder, light therapy is done with extra care and close monitoring by your psychiatrist. If you notice yourself speeding up, tell them that day." [synthesis]

A4. Combination with other treatments and chronotherapies

What sources say: light may work alone, but some people do better combined with an antidepressant or psychotherapy [source: Mayo]. ISBD says integrating light with other chronotherapeutic strategies "may enhance long-term efficacy"; it describes wake therapy as highly effective but not widely available, supports reducing evening and night-time light and keeping the bedroom dark, and recommends daytime outdoor light, regular exercise, consistent sleep schedules and a screen curfew; it gives no protocol for combining light with wake therapy or sleep-phase advance [source: ISBD 2025 full text]. CANMAT 2023 keeps sleep deprivation (wake therapy) as a third-line recommendation for major depression, notes that a recent meta-analysis found no benefit, and warns it may trigger hypomania in susceptible people not previously diagnosed with bipolar disorder [source: CANMAT 2023, Lam et al. 2024]. These chronotherapies are prescriber- or specialist-led.
Example language (illustrative): "Some people do best with light plus medication or therapy. Which combination suits you is something to plan with your doctor." [synthesis]
Watch for: clients adding other chronotherapies or extra light on their own. Working: every component is known to the prescriber. [synthesis]

A5. Eye-safety and medication screening (by the medical team)

What sources say: ISBD lists retinal disease, photosensitising medicines (sulphonamides, chloroquine, St John's wort) and light hypersensitivity or photophobia as contraindications; people with reduced vision, recent vision changes or past eye disease should have a comprehensive eye examination first; after LASIK surgery evidence is limited, and use is considered only after a waiting period and an ophthalmologist's review [source: ISBD 2025 full text]. People with glaucoma, cataracts or diabetes-related eye damage should consult an eye specialist first [source: Mayo]. NHS: light therapy may not be suitable with certain eye conditions or medicines that increase light sensitivity [source: NHS]. UBC: may be harmful in retinal eye disease [source: UBC light devices].
Therapist's part: ask about these and include them in your referral note; never judge suitability yourself [synthesis].
Example language (illustrative): "Because light therapy can affect the eyes, your doctor may want an eye check first, especially with eye conditions or certain medicines. Shall we add that to your questions?" [synthesis]
Watch for: eye conditions or light-sensitising medicines or supplements (such as St John's wort) not yet disclosed. Working: the prescriber has the full list. [synthesis]

Part B. The psychotherapist's interventions

B1. Recognising a seasonal pattern

Purpose: identify clients whose depression may recur with the seasons so they can be assessed medically and offered seasonal-specific treatment.
When: low mood, oversleeping, low energy, increased appetite or withdrawal that clients link to autumn and winter; recurrent dips at the same time of year [synthesis; NHS gives the two-year same-season pattern as a diagnostic feature].
Steps: (1) map mood across the past several years month by month on a timeline with the client; (2) note onset and remission months, sleep, appetite, energy, social withdrawal; (3) ask about any past periods of unusually high mood, reduced need for sleep or risk-taking (bipolar screen); (4) ask about eye conditions and current medicines and supplements, including St John's wort; (5) note physical symptoms that could have a medical cause (e.g. thyroid symptoms) [synthesis informed by NHS; UBC; Rohan et al. 2015; Psychopharmacology Institute summary of ISBD].
Example language (illustrative): "When we map your mood across the year, the low patches seem to begin around the same month each autumn. That pattern is worth taking to your GP, because there are specific treatments for it."
Watch for: a seasonal story that hides a summer-pattern or bipolar course; worsening that is not seasonal at all [synthesis].

B2. Referral and collaborative care

Purpose: get a medical assessment and a supervised plan rather than self-treatment, which UBC advises against [source: UBC light devices; NHS].
Steps: (1) with consent, write to the GP, psychiatrist or sleep specialist summarising the seasonal timeline, any bipolar history, eye conditions and medicines the client reports, current risk, and the client's preferences; (2) agree how you will share observations (side effects, mood elevation, adherence) during treatment; (3) suggest an eye-specialist review is considered where the client reports eye disease [synthesis; contents drawn from Psychopharmacology Institute summary of ISBD; Mayo].
Example language (illustrative): "I'd like to write to your doctor so they can check whether light therapy is safe and suitable for you. I won't recommend a device or a routine myself; that's their call."
Watch for: the client starting with an online purchase before review; respond with information, not prohibition [synthesis].

B3. Psychoeducation

Purpose: give an accurate, balanced picture so the client can take part in decisions.
Content (sources): what a light box is and why timing matters to the body clock; that guidelines specify how bright, how long and when, and that the doctor sets these; expected time course (improvement often within weeks); common side effects; the bipolar and eye cautions; that devices differ and UV-filtered SAD devices are advised; that NHS considers the evidence insufficient to provide it routinely while CANMAT supports it; that CBT and antidepressants are alternatives or partners; that seasonal depression often recurs each winter [source: NHS; Mayo; UBC; ISBD 2025 abstract; Rohan et al. 2015].
Steps [synthesis]: (1) ask what the client already knows and where it came from; (2) cover the points above in short, plain chunks, checking understanding as you go; (3) give the NHS or UBC patient page in writing; (4) note any questions for the prescriber.
Example language (illustrative): "Light therapy is a medical treatment that uses a special lamp each day. Guidelines lay out exactly how it should be done, and your doctor will set that for you. What I can help with is fitting it into your day and keeping an eye on how you're doing."
Watch for: overselling ("it's just a lamp") or dismissing it; correct both [synthesis].

B4. Supporting informed consent and shared decision-making

Purpose: help the client weigh light, medication, psychotherapy or combinations against their values and circumstances, in line with CANMAT 2023's recommendation of shared decision-making and its attention to preference, availability and cost [source: CANMAT 2023, Lam et al. 2024].
Steps: (1) list the options the medical team has offered; (2) explore practicalities: cost and lack of reimbursement, time each day, household routines, travel [source: Mayo; Psychopharmacology Institute summary]; (3) note that CBT-SAD performed comparably acutely in one trial [source: Rohan et al. 2015]; (4) write down questions for the prescriber; (5) respect the decision, including declining [synthesis].
Example language (illustrative): "Some people prefer a lamp, some prefer therapy skills, some prefer medication, and some combine them. What would fit your life this winter?"
Watch for: pressure from others, financial strain, or a client hoping you will choose for them [synthesis].

B5. Adherence and routine support (never changing the prescription)

Purpose: daily use is what makes light therapy work; ISBD calls daily sessions critical and names adherence, cost, lack of reimbursement and device variability (and, in low- and middle-income countries, access to reliable devices and electricity) as barriers [source: ISBD 2025 full text].
Steps: (1) ask the client what schedule the prescriber set; (2) plan where the box will sit and what the client will do during sessions (breakfast, reading, emails) [source: Psychopharmacology Institute summary; Mayo]; (3) anchor the session to a fixed daily cue at the time the prescriber set; (4) problem-solve barriers (oversleeping, shift work, travel, children); (5) suggest a simple daily log of use, mood and side effects to share with the prescriber; (6) if the schedule is not workable, help the client take that to the prescriber rather than improvising [synthesis].
Example language (illustrative): "Your doctor gave you a plan for the lamp. Let's work out where it lives and what you'll do while you sit at it. If the plan doesn't fit your routine, that's something to ask your doctor about."
Watch for: self-adjusting (longer sessions to 'speed it up', evening use, stopping when well); route to the prescriber [synthesis].

B6. Monitoring mood, hypomania, side effects and risk

Purpose: detect switching, worsening or side effects early and pass them on.
Steps: (1) use the patient-reported scales the team uses, such as PHQ-9, GAD-7 and a mania rating (the ISBD summary names the Young Mania Rating Scale), reviewing scores with the client; ISBD recommends regular follow-up with patient-centred outcome measures to catch early warning signs [source: ISBD 2025 full text; Psychopharmacology Institute summary of ISBD; Progress in Mind report on CANMAT 2023]; (2) ask each session about sleep, energy, irritability, racing thoughts, headaches, eye strain, dizziness, nausea and agitation [source: ISBD 2025 full text; Rohan et al. 2015; synthesis]; (3) contact the prescriber the same day for signs of hypomania, mixed states, worsening depression or rising suicidal thoughts; ISBD's own patient advice in those situations is prompt contact with the clinician and urgent care in a crisis [source: ISBD 2025 full text].
Example language (illustrative): "You've mentioned sleeping much less and feeling wired. That can be a reaction to light therapy, and your doctor needs to know today."
Watch for: clients enjoying elevated energy and not wanting to report it [synthesis].

B7. CBT for seasonal depression (CBT-SAD)

Purpose: a psychological treatment specific to winter depression, usable alongside light therapy or as an alternative the client chooses [source: Rohan et al. 2015].
Format (trial version): closed groups of 4–8, 12 sessions over 6 weeks, twice weekly, 90 minutes, led by a psychologist with a co-therapist, compressed to finish before spring [source: Rohan et al. 2015]. Individual adaptation is [synthesis].
Components, in order (paraphrased): (1) psychoeducation about winter depression; (2) behavioural activation: identifying and scheduling pleasant activities to counter winter loss of interest; (3) cognitive restructuring of usual depressive thoughts and winter-specific ones, such as thoughts about darkness and weather; (4) relapse prevention: a personal plan to recognise early negative thoughts about winter and behaviour change as cues to use the skills [source: Rohan et al. 2015]. Session sequence in the therapist guide (chapter titles, paraphrased): 1 introduction to the group; 2 symptoms, prevalence and causes of SAD; 3 how activities relate to mood and thoughts; 4 doing more to feel better; 5 how thinking influences feeling; 6 cognitive distortions; 7 evaluating automatic thoughts; 8 rational responses; 9 core beliefs; 10 evaluating core beliefs; 11 maintaining gains and relapse prevention; 12 review and farewell; preceded by chapters on therapist background and group logistics and followed by fidelity checklists [source: SIU-BDU library catalogue table of contents; Oxford Academic chapter pages]. The detailed content of each session is [uncertain].
Example language (illustrative): "When you notice 'It's dark, there's no point going out', let's treat that as a thought to examine, then plan one thing for this evening that's still worth doing in the dark."
Watch for: activities that depend on good weather; build indoor and dark-evening options [synthesis].

B8. Routine and light-exposure habits around treatment

Purpose: support the regular rhythms that sources say may complement light therapy.
Steps: discuss consistent sleep and wake times, regular exercise, daytime outdoor light, reducing evening and night-time light (including a screen curfew) and a dark bedroom [source: ISBD 2025 full text], framed as general habits, not as a substitute for the prescribed treatment [synthesis].
Example language (illustrative): "A steady wake-up time and some time outdoors can support the treatment your doctor has set. They're extras, not a replacement." [synthesis]
Watch for: habits used as a substitute for the prescribed treatment, or rigid rules that add stress. Working: a regular daily rhythm the client can keep. [synthesis]

B9. Crisis and safety planning

Purpose: seasonal depression can be severe; the Rohan trial excluded acute serious suicidal intent [source: Rohan et al. 2015].
Steps: standard risk assessment, a written safety plan with warning signs, coping steps, contacts and crisis lines, and agreement on when to contact the prescriber or emergency services; review it at the start of each season [synthesis].
Example language (illustrative): "If winter gets very dark for you, here is what we've agreed you'll do first, and who you'll call." [synthesis]
Watch for: hopelessness at the start of winter, or worsening despite treatment. Working: the plan is current and the client knows when to use it. [synthesis]

B10. Seasonal relapse prevention and support after the course ends

Purpose: many people need treatment every winter [source: NHS]; CBT-SAD ends with a personal relapse-prevention plan [source: Rohan et al. 2015].
Steps: (1) before late summer, review the past season's early signs; (2) agree when the client will contact the prescriber about restarting any treatment; (3) rehearse CBT skills and an activity plan for dark months; (4) schedule a booster session at the client's usual onset time [synthesis].
Example language (illustrative): "Your first signs last year were sleeping in and cancelling plans in October. Let's put a reminder in your calendar for September to check in with your doctor and with me."
Watch for: plans that lapse over the summer, or a client who waits until symptoms are well established before acting. Working: early contact with the prescriber and you at the first signs. [synthesis]

5. Handling problems

Sources address side effects, bipolar risk and adherence; the rest is [synthesis].

Client asks you how long, how bright or when to use the lamp. Say plainly that guidelines set these and the prescriber or sleep specialist decides them; help the client write the question down and contact them [synthesis].
Side effects (headache, early waking, evening sleepiness, feeling overactive). These were seen in the Rohan trial and managed by the investigators adjusting the regimen [source: Rohan et al. 2015]. Your response: record, reassure without minimising, and pass to the prescriber promptly; do not suggest changes yourself [synthesis].
Signs of hypomania or a mixed state. Treat as urgent: contact the prescriber the same day and follow the agreed plan; ISBD advises prompt clinician contact and, when hypomanic symptoms appear, reducing or stopping treatment, a decision you route to the prescriber [source: ISBD 2025 full text]. Revisit the safety plan [synthesis].
Worsening depression or rising suicidal thoughts during light therapy. Full risk assessment, safety plan, same-day contact with the prescriber, emergency services if risk is imminent; ISBD flags these as needing prompt attention, with clinician contact and urgent care in a crisis [source: ISBD 2025 full text on prompt contact; synthesis on procedure].
Non-adherence (forgetting, oversleeping, no time). Explore without blame; use cue-anchoring, location planning and logs (B5); if the prescribed routine is unworkable, encourage the client to raise it with the prescriber, who can review whether the routine can be adapted [source: ISBD 2025 abstract; synthesis].
Ambivalence or scepticism ('a lamp can't fix this'). Validate; give balanced information, including that NHS considers the evidence insufficient for routine provision while CANMAT 2023 lists it first-line for winter depression, and that CBT-SAD is an evidence-based alternative [source: NHS; CANMAT 2023; Rohan et al. 2015]. Do not argue the client into or out of it [synthesis].
Self-treatment with an unsuitable device or no medical review. Explain the eye and bipolar cautions and the device features sources recommend; encourage a GP review; record that you advised this [source: UBC light devices; Mayo; NHS; synthesis].
Eye discomfort or a newly disclosed eye condition or photosensitising medicine (e.g. St John's wort). Pass on to the prescriber and suggest an eye review is considered [source: Psychopharmacology Institute summary of ISBD; Mayo].
No response after several weeks. Encourage a medical review of the diagnosis and plan (CANMAT 2023's approach to difficult-to-treat depression starts with reviewing diagnosis, adherence and comorbidity) and offer CBT-SAD or other psychotherapy [source: Progress in Mind report on CANMAT 2023; Rohan et al. 2015].
Stuck in CBT-SAD (passivity, 'nothing to do in winter'). Use smaller, indoor and dark-friendly activity steps; examine winter-specific beliefs as hypotheses [source: Rohan et al. 2015 for components; synthesis for tactics].
Overwhelm (too many tasks: lamp, logs, homework). Prioritise with the client and the team; simplify logs; space CBT homework [synthesis].
Rupture: client feels you are 'pushing a lamp' or, conversely, refusing to help with it. Name the boundary transparently (you support, the prescriber prescribes), repair by returning to the client's goals [synthesis].
Shift workers, travel across time zones, polar or high-latitude winters, pregnancy, children and adolescents, older adults. The cited sources do not address these; refer to the prescriber or a sleep specialist [uncertain].
Client stops when well in spring and relapses next winter. Build a seasonal relapse-prevention plan (B10) [source: NHS; Rohan et al. 2015].

Sources

Sources:

Sources added at verification (October 2026):

Cited works:

Lam RW , Kennedy SH, Adams C, et al. (2024). Canadian Network for Mood and Anxiety Treatments (CANMAT ) 2023 Update on Clinical Guidelines for Management of Major Depressive Disorder in Adults. Canadian Journal of Psychiatry 69(9); DOI 10.1177/07067437241245384
Geoffroy PA, Palagini L, Henriksen TEG, Bourgin P, Garbazza C, Gronfier C, Esaki Y, Fernandez DC, Lam RW, Lee HJ, Lejoyeux M, Maruani J, Martiny K, Murray G, Riemersma-Van Der Lek RF, Ritter P, Schulte PFJ, Smith DJ, Terman M, Zeitzer JM, Sit DK (2025). Light therapy for bipolar disorders: clinical recommendations from the International Society for Bipolar Disorders (ISBD) Chronobiology and Chronotherapy Task Force. Dialogues in Clinical Neuroscience 27(1):249–264; DOI 10.1080/19585969.2025.2533806 (full text via PubMed Central; listed above).
Rohan KJ (2008 online; 2009 print per library catalogue). Coping with the Seasons: A Cognitive-Behavioral Approach to Seasonal Affective Disorder. Therapist Guide. Oxford University Press, Treatments That Work (chapter titles and abstracts; session text and any companion client workbook not reviewed here) [uncertain for workbook].
NICE guideline NG222, Depression in adults (2022): final recommendation wording on light therapy [uncertain]. SLTBR: no clinical or device guidance cited.

← Previous · IX-031Hyperbaric oxygen for brain injury and PTSD (contested)Next · IX-033 →Dawn simulation