Dark therapy and blue-light blocking

1. Introduction

Version followed: the practice recommendations of the International Society for Bipolar Disorders (ISBD) task force on chronotherapy and chronobiology (Gottlieb et al., 2019), with the Henriksen et al. (2016) randomised placebo-controlled trial as the key trial of blue-blocking glasses, and the Trondheim blue-depleted ward-lighting work (Scott et al., 2021; Kallestad et al., 2024 preprint) for the whole-ward variant. This guide describes the methods at a descriptive level only; it gives no schedules, durations or clock times. These are set by the prescriber or treating team.

What it is. Dark therapy is the use of extended darkness as an add-on to standard medical treatment of acute mania. Its practical successor, sometimes called "virtual darkness", uses amber or orange blue-blocking lenses (or blue-depleted room lighting) so that the brain receives a physiological signal of darkness while the person can still see. The rationale given by the developers: evening and night light suppresses melatonin and shifts the circadian clock, and short (blue) wavelengths are the most potent; a blue-sensitive retinal photoreceptor outside the rods and cones signals the body clock in the suprachiasmatic nucleus. Removing that signal is proposed to stabilise disrupted circadian rhythms, improve sleep and reduce manic over-activation. [source: Henriksen thesis summary, University of Bergen 2020; Phelps 2016, Psychiatric Times; Gottlieb et al. 2019]

Who delivers it and status. This is a medical adjunct ordered and supervised by the psychiatric team, so far mainly in hospital. It is not a psychotherapy. As of October 2026, per the sources consulted, the ISBD task force supports hospital-based adoption of dark therapy (including blue-blocking lenses) as an adjunct in acute mania and considers it contraindicated in acute bipolar depression; outpatient and maintenance use need further study. [source: Gottlieb et al. 2019] Blue-blocking glasses are eyewear, not a licensed medicine; no regulator approval of any lens for treating mania was found in the sources consulted [uncertain]. Whether NICE (CG185) or the CANMAT/ISBD bipolar guideline address dark therapy is [uncertain]. This guide is written for the psychotherapist working alongside the prescriber: your interventions are psychoeducation, collaborative care, monitoring, relapse-prevention integration and referral.

2. Framework

The sources describe a medical adjunct, not a staged therapy, so there is no published phase model or session count for the psychotherapist. The phases below organise the therapist's work around the course of a manic episode [synthesis], anchored where possible in the sources.

Phase A: acute mania, usually inpatient.

Treatment: the team may add dark therapy, blue-blocking lenses or blue-depleted ward lighting to standard medication; trials used fixed nightly windows over a defined treatment period, specified in the papers and set by the team. [source: Gottlieb et al. 2019; Henriksen et al. 2016 as summarised by Phelps 2016 and Mylona & Floros 2022]
Therapist goals: brief, low-stimulation contact if you are involved at all; liaison with the team; keeping the outpatient relationship alive. [synthesis]
Format: short contacts, no exploratory work during acute mania. [synthesis]
Move on when: the team judges the acute episode settled and discharge planning starts. [synthesis]

Phase B: recovery and discharge.

Goals: help the client make sense of the episode and the treatment; a shared picture of the role sleep and light played; clarify, with the prescriber, whether any lens use continues at home (evidence for outpatient use is limited; this is the prescriber's decision). [source: Gottlieb et al. 2019] [synthesis for therapist tasks]
Format: weekly sessions are a common default [synthesis]; no source specifies a count.
Move on when: mood is stable, the client has a written relapse-prevention plan, and the team's follow-up is arranged. [synthesis]

Phase C: maintenance and relapse prevention.

Goals: regular daily routines and sleep schedules, which the ISBD task force regards as relevant to maintenance; integration with an established bipolar psychological approach (for example interpersonal and social rhythm therapy, IPSRT, or an adapted CBT for insomnia); early-warning monitoring. [source: Gottlieb et al. 2019]
Format: per the chosen psychotherapy model; this guide does not replace those manuals.
Re-entry to Phase A: early signs of mania, especially shortened sleep, trigger a prompt medical review. [synthesis]

3. Guiding principles

The prescriber owns the treatment. Starting, timing, continuing or stopping lenses or dark therapy is a medical decision; you route every such question to the prescriber or sleep specialist. [source: Gottlieb et al. 2019 describe team-adjusted timing]
Adjunct, never substitute. All trials added darkness or lenses to standard medication; never present it as an alternative to mood stabilisers or antipsychotics. [source: Gottlieb et al. 2019; Henriksen thesis summary]
Polarity matters. Darkness and blue-blocking are discussed for mania; the ISBD task force considers dark therapy contraindicated in acute bipolar depression, and light therapy and sleep deprivation contraindicated in mania or mixed states. Practical meaning: always ask which pole the client is in before any conversation about light. [source: Gottlieb et al. 2019]
Evidence is small and early. One RCT in inpatient mania, a small pilot of literal darkness, case reports and a negative-to-mixed outpatient sleep study. Practical meaning: speak of it as promising, not proven, and attribute claims. [source: Mylona & Floros 2022 via Psychiatric Times; NeuRA 2021; Gottlieb et al. 2019]
Not all "blue-light" glasses are the same. Clear or lightly tinted consumer lenses filter only a fraction of blue light; trial lenses were amber/orange. Practical meaning: never equate a shop product with the trial intervention. [source: AOP report of Cochrane review 2023]
Safety is part of the method. Darkness and tinted lenses reduce vision; watch falls, driving and mood shifts. [source: Phelps 2016 for driving; falls: synthesis]
Watch for a depressive dip. Some trial participants developed depressive symptoms that resolved when the team changed lens use. Practical meaning: report low mood promptly. [source: Gottlieb et al. 2019]
Rhythm is the shared language. Sleep, light and daily routine link the medical adjunct to psychological relapse prevention. [source: Gottlieb et al. 2019; synthesis]
Marketing is not evidence. Advertising regulators have ruled against unsupported sleep and eye-health claims for blue-light lenses. [source: ASA 2022; AOP 2017]
Collaborative, transparent stance. With the client's consent, share observations with the team and tell the client what you will share. [synthesis]

4. Intervention inventory

Part A describes how the medical treatment is delivered, as published, so you can explain it and spot problems. It is descriptive only: schedules, durations and lens specifications are deliberately left out and belong to the prescriber. Part B gives the psychotherapist's own interventions.

A1. Dark therapy (literal darkness) as an adjunct in inpatient mania

Purpose / when used: added by the team to usual medication for hospitalised patients in acute mania. The ISBD task force rates the evidence as a pseudorandomised inpatient trial (Barbini et al., 2005) and finds faster reduction in manic symptoms than treatment as usual, with reduced antipsychotic use in the controlled trials. An earlier NIMH single-case report (Wehr et al., 1998) described a rapid-cycling patient who stayed well with extended nightly darkness. [source: Gottlieb et al. 2019; Phelps 2016 for the case report]
How it is delivered (descriptive): the patient spends a prescribed, extended nightly period in a darkened room on the ward, alongside standard treatment; the schedule and length of the course are set by the team and are given in the trial papers. [source: Gottlieb et al. 2019]
Practical limits named by sources: literal darkness is hard to deliver and to tolerate; this drove the shift to blue-blocking lenses and blue-depleted lighting. [source: Gottlieb et al. 2019; Phelps 2016]
Contraindication: the ISBD task force considers dark therapy contraindicated in the acute treatment of bipolar depression; no studies of dark therapy for bipolar depression were found. [source: Gottlieb et al. 2019]
Therapist relevance: you will meet this mainly through clients' accounts of a hospital stay; explain it as an add-on the team chose, not as isolation or punishment. [synthesis]
Example language (illustrative): "On some wards, people with mania spend long nights in a darkened room as well as taking their usual medication. It's an add-on the team chose, not a punishment." [synthesis]
Watch for: clients describing a darkened room as isolation or coercion. Working: the client understands why it was used. [synthesis]

A2. Amber/orange blue-blocking glasses ("virtual darkness") as an adjunct in mania

Purpose / when used: to give the effect of darkness while the patient remains active and able to see. Key trial: Henriksen et al. (2016), Bipolar Disorders 18(3):221–232, a randomised placebo-controlled trial in hospitalised patients with mania; amber (orange) blue-blocking lenses versus clear placebo lenses, added to treatment as usual, worn during a fixed nightly window set by the protocol, over a short course. [source: SLTBR citation page; Phelps 2016; Henriksen thesis summary, UiB 2020]
Reported results: rapid decline in manic symptoms compared with placebo (Young Mania Rating Scale), reduced motor activity, better sleep efficiency and fewer night awakenings, despite less intensive medication in the amber group. The ISBD task force classes this as Level II evidence. [source: Henriksen thesis summary; Mylona & Floros 2022 via Psychiatric Times; Gottlieb et al. 2019] Trial limitations noted by commentators: small sample, smaller than planned, and imperfect blinding because blue-light glasses are widely known. [source: Phelps 2016]
Adverse effects reported: depressive symptoms in a subset of the treatment group, which resolved within hours when the team delayed or stopped lens use; the task force notes that sensitivity to antidopaminergic medicines may increase, so lens timing is adjusted by day-to-day observation. [source: Gottlieb et al. 2019] Caution against wearing amber lenses while driving at night. [source: Phelps 2016]
Outside acute mania: in euthymic outpatients with insomnia, a 2020 study found a favourable circadian shift but no change in actigraphic sleep, subjective sleep quality or mood; an uncontrolled case series reported self-rated insomnia improvement in a minority-to-half of participants. Maintenance and outpatient use are not established. [source: Mylona & Floros 2022 via Psychiatric Times; NeuRA 2021; Gottlieb et al. 2019]
Who decides: the prescriber, who also decides lens type, schedule and when to stop. [source: Gottlieb et al. 2019 on team-adjusted timing]
Example language (illustrative): "The orange glasses block the blue light that tells your body clock it's daytime. Whether and when you wear them is up to your psychiatrist." [synthesis]
Watch for: low mood, drowsiness or night driving while wearing them. Working: effects are reported to the prescriber promptly. [synthesis]

A3. Blue-depleted ward lighting (whole-unit "dark therapy")

Purpose / when used: to remove evening blue light from the whole acute ward, avoiding reliance on individual lens adherence. At St Olavs University Hospital, Trondheim, programmable LED lighting switches off blue diodes in the evening, windows and TVs carry blue-blocking filters, and contact-free radar monitoring replaces night checks with a torch. [source: Scott et al. 2021]
Reported results: a pragmatic RCT of 476 admissions (all diagnoses) found no difference in length of stay, but better clinician-rated global improvement, lower illness severity at discharge and lower predicted aggression, with no difference in patient-rated side effects or satisfaction. Results were reported as a medRxiv preprint (March 2024, not peer reviewed at that time); peer-reviewed publication status not checked [uncertain]. No separate result for mania was reported. [source: Kallestad et al. 2024 preprint]
Cautions named by the authors: take care with daytime light intensity on units admitting people with acute mania; some medicines may change light sensitivity; adherence varies because patients move around. [source: Scott et al. 2021]
Example language (illustrative): "On this ward the lights change colour in the evening to cut out blue light. It's part of the ward's routine, alongside your treatment." [synthesis]
Watch for: worry or confusion about the ward lighting. Working: questions go to the ward team. [synthesis]

A4. Consumer "blue-light" glasses, screen filters and marketing claims

What they are: mostly clear or lightly tinted lenses sold for screen use, eye strain or sleep. A Cochrane review (17 RCTs, 2023) found they probably make no difference to eye strain or visual performance over the short term, and effects on sleep are unclear; no conclusions on long-term retinal health. A review author noted typical consumer lenses filter only about 10–25% of blue light and that filtering much more requires an obvious amber tint. [source: AOP news on Cochrane review CD013244.pub2]
Regulatory actions on claims: the UK Advertising Standards Authority (July 2022) upheld a complaint against a blue-light glasses advertiser's claims of being clinically proven to stop melatonin suppression and improve sleep, finding the evidence inadequate. The UK General Optical Council (2017) fined Boots Opticians £40,000 after the ASA found its claims that screen and LED blue light damages the retina, and that its lenses protect against it, misleading. [source: ASA ruling 2022; AOP 2017]
Conflicts to notice: some clinical commentary promoting amber lenses also names specific products and retailers, and one author's clinic sells lenses. [source: Phelps 2016] Read promotional material, including clinician-authored, with that in mind.
Therapist relevance: clients may buy products on their own. You do not recommend brands or tell a client to use or stop them; you help them take the question to the prescriber and correct overclaims ("these are proven to prevent mania") with the evidence status above. [synthesis]
Example language (illustrative): "Most shop 'blue-light' glasses are not the same as the orange lenses tested in hospital. Shall we take your question to your psychiatrist?" [synthesis]
Watch for: overclaims such as 'these prevent mania', or spending on products. Working: the client weighs claims against the evidence. [synthesis]

Part B: the psychotherapist's interventions. The sources on dark therapy do not describe a psychotherapist's role; the steps below are synthesis built on the cautions and recommendations they do give, and are marked accordingly.

B1. Recognising when to suggest a medical review

Purpose / when: shortened sleep, reduced need for sleep, rising energy or activity, or a client asking about light or darkness treatments. Light and sleep loss are linked to mania in the ISBD review. [source: Gottlieb et al. 2019] [synthesis for steps]
Steps: (1) ask about sleep timing and duration in every session during risk periods; (2) compare with the client's relapse signature; (3) if early signs appear, name them and ask permission to contact the prescriber the same day, or help the client call; (4) document what you observed and what was agreed.
Example language (illustrative): "You've slept much less three nights running and you feel great. Last time that was the first sign. Can we ring your psychiatrist together now?"
Watch for: minimising ("I just don't need sleep"). Working: the client contacts the team early and agrees to it in future plans.

B2. Psychoeducation on light, darkness and the body clock

Purpose / when: after an inpatient stay in which lenses or dark therapy were used, or when a client asks about blue-light products.
Steps: (1) explain the published rationale simply: evening blue light tells the body clock it is daytime; blocking it creates a darkness signal [source: Henriksen thesis summary; Phelps 2016]; (2) state status honestly: one small RCT and small studies in inpatient mania, promising but not established, not proven for prevention or outpatient use [source: Gottlieb et al. 2019; Mylona & Floros 2022]; (3) distinguish amber trial lenses from clear consumer lenses [source: AOP on Cochrane 2023]; (4) say that whether to use them, when and for how long is for the prescriber.
Example language (illustrative): "The orange glasses used in hospital studies block far more blue light than most 'screen glasses'. Whether they suit you, and how to use them, is a question for Dr X."
Watch for: over-enthusiasm leading to self-treatment; catastrophic beliefs about screens. Working: client can explain the idea in their own words and knows whom to ask.

B3. Supporting informed consent and shared decision-making

Purpose / when: the team proposes lenses, dark therapy or a blue-depleted ward, or the client asks about continuing at home. [synthesis]
Steps: (1) help the client list questions: why this, what evidence, what side effects (including low mood and drowsiness), what if it doesn't suit, does it change medication [source for side effects: Gottlieb et al. 2019]; (2) rehearse asking them; (3) check understanding after the consultation; (4) respect capacity and legal frameworks on the ward; during acute mania, decisions are the team's responsibility under local law [synthesis].
Example language (illustrative): "What would you want to know before agreeing? Let's write it down for your ward round."
Watch for: the client feeling it is imposed. Working: the client can state reasons and risks.

B4. Adherence and ambivalence conversations (never advising a change)

Purpose / when: clients dislike losing evening screens, tinted vision, or feel stigmatised wearing lenses; patients resist giving up evening screen time. [source: Phelps 2016]
Steps: (1) explore both sides with open questions; (2) link to the client's own goals (sleep, avoiding admission); (3) problem-solve barriers only within the plan the prescriber set; (4) if the client wants to stop or change, support them to raise it with the prescriber rather than deciding with you.
Example language (illustrative): "Part of you wants the evenings back, part of you remembers how fast things escalated. Shall we take both to your psychiatrist?"
Watch for: covert stopping; you being drawn into deciding. Working: ambivalence is voiced openly in the team.

B5. Monitoring and passing on side effects and warning signs

Purpose / when: throughout any period of use.
Steps: (1) ask about low mood, as depressive symptoms appeared in some trial participants and resolved when the team adjusted use [source: Gottlieb et al. 2019]; (2) ask about drowsiness and fatigue (slight excess fatigue was reported with blue-depleted evening light in healthy volunteers) [source: Scott et al. 2021]; (3) ask about falls, trips and night driving with tinted lenses [source: Phelps 2016 for driving; falls synthesis]; (4) note any switch towards depression or mixed features; (5) pass observations to the prescriber with consent and tell the client what you shared.
Example language (illustrative): "Since starting the glasses, any change in your mood, energy or sleepiness? Any stumbles in the dark?"
Watch for: sudden low mood, suicidal thoughts, injuries. Working: issues reach the prescriber within the agreed time.

B6. Safety in darkness and on the ward

Purpose / when: dark therapy and dim, amber-filtered vision reduce visibility; acute mania increases impulsivity and activity. Falls in darkness are not addressed in the sources found [uncertain]; the following is synthesis.
Steps: (1) if you see a client on a ward using darkness or lenses, follow ward safety procedures and do not turn lights on or off yourself; (2) at home, encourage the client to discuss with the prescriber or sleep specialist safe night movement (e.g. clear routes, safe night lighting compatible with the plan) and older age, sedation or mobility problems as risk factors; (3) remind that tinted lenses should not be worn for night driving [source: Phelps 2016]; (4) report any injury.
Example language (illustrative): "If you need the toilet at night, how will you get there safely? Let's check that with the team."
Watch for: sedation plus darkness; alcohol. Working: no injuries; safety plan written.

B7. Sleep and routine work (sleep hygiene within a bipolar frame)

Purpose / when: recovery and maintenance; the ISBD task force emphasises regular daily routines and sleep schedules for maintenance, and notes one trial of CBT for insomnia adapted for bipolar disorder in euthymic patients showing relapse-prevention benefit. [source: Gottlieb et al. 2019]
Steps: (1) map current sleep, wake, meal and activity times with a diary; (2) aim for regular rise and bedtimes agreed with the client; (3) reduce evening stimulation and bright screens as general sleep hygiene, without prescribing lenses or light schedules [synthesis]; (4) avoid standard sleep-restriction techniques unless adapted for bipolar and agreed with the prescriber, since sleep loss is linked to switches into mania [source: Gottlieb et al. 2019 on sleep loss; synthesis for the caution]; (5) refer to a sleep specialist for persistent insomnia or suspected sleep disorders.
Example language (illustrative): "Let's find a wake-up time you can keep on weekends too. Steadiness matters more than perfection."
Watch for: sleep reduction drifting into hypomania. Working: diary shows regular timing; fewer early-warning episodes.

B8. Integrating into bipolar relapse prevention

Purpose / when: after any episode. IPSRT has acute and maintenance evidence for bipolar depression and is listed as a third-line option in CANMAT/ISBD guidance, per the ISBD review. [source: Gottlieb et al. 2019]
Steps: (1) use your chosen manualised approach (IPSRT, CBT or family-focused work); (2) add to the relapse-prevention plan: personal early signs, sleep threshold for calling the team, the prescriber's instructions on any light or lens use, emergency contacts; (3) share the plan with the team with consent; (4) review it at each session in high-risk seasons or life events. [synthesis]
Example language (illustrative): "Let's put your psychiatrist's instructions about the glasses in your plan, word for word, so you don't have to remember."
Watch for: plan not shared or outdated. Working: early contacts when signs appear.

B9. Crisis and safety planning

Purpose / when: mania (risk-taking, aggression, financial harm) and the post-manic depressive phase (suicide risk). [synthesis]
Steps: (1) standard risk assessment each session in risk phases; (2) a written safety plan covering warning signs, coping, supports and crisis numbers; (3) lethal-means counselling about safe storage of medicines with family where appropriate; (4) urgent same-day medical contact if suicidal thinking emerges, including any low mood during lens use.
Example language (illustrative): "If your mood drops after you leave hospital, who will you tell first, and what will they do?"
Watch for: rapid mood shifts. Working: client and family use the plan.

B10. Support after the treatment ends

Purpose / when: when the team stops lenses or dark therapy, or after discharge from a blue-depleted ward. [synthesis]
Steps: (1) ask how the client understood the ending; (2) monitor sleep and mood closely in the following weeks; (3) keep the routine work going; (4) route any wish to restart or buy products to the prescriber.
Example language (illustrative): "Now the glasses have stopped, let's keep a close eye on your sleep together for a while."
Watch for: sleep shortening after discharge. Working: stable routines, early help-seeking.

5. Handling problems

The sources address few of these problems directly; guidance is [synthesis] unless a source is named.

Client wants to self-treat with glasses or darkness instead of medication. Name the evidence: every trial added darkness or lenses to standard treatment [source: Gottlieb et al. 2019]. Explore the wish (side effects? identity?) and take it to the prescriber together. Do not endorse or forbid. [synthesis]
Client is low or depressed and asks about "dark therapy". Explain that the ISBD task force considers dark therapy contraindicated in acute bipolar depression [source: Gottlieb et al. 2019]; route mood concerns to the prescriber urgently; complete a risk assessment.
Low mood appears while lenses are in use. Treat as a reportable effect: depressive symptoms in some trial participants resolved when the team changed use [source: Gottlieb et al. 2019]. Contact the prescriber the same day; never suggest the client stops on their own. [synthesis]
Non-adherence (glasses left off, screens back on). Normalise; patients commonly resist losing evening screen time [source: Phelps 2016]. Use B4; report to the prescriber, who decides whether to continue. [synthesis]
Bought a consumer product believing it is the same as the trial lenses. Share the Cochrane and regulator findings neutrally [source: AOP 2023; ASA 2022]; help them ask the prescriber; avoid shaming. [synthesis]
Overvalued beliefs about light and screens (fear, rigid avoidance, preoccupation). Explore function; in mania, may be part of the episode and should be reported; in anxiety, treat as you would other safety behaviours, coordinated with the team. [synthesis]
Falls, injuries or near-misses in darkness, or night driving in tinted lenses. Report immediately to the team; review the safety plan (B6) [source: Phelps 2016 for driving; falls synthesis, not found in sources].
Stuck: client remains sleepless and escalating despite the plan. This is a medical-review trigger, not a psychotherapy problem: same-day contact with the prescriber or crisis team. [synthesis]
Rupture: client feels the ward "kept them in the dark" or felt coerced. Validate the experience, help them describe it, and support a complaint or debrief with the team if they wish; clarify the rationale the team gave. [synthesis]
Overwhelm with routine demands. Shrink to one anchor (fixed rise time) before adding others. [synthesis]
Conflicting advice (online sources, product sellers, clinicians). Point to the evidence status and the prescriber as decision-maker; note commercial interests where present [source: Phelps 2016 disclosures; ASA 2022]. [synthesis]
Client wants to know if it works long term. Say honestly that outpatient and maintenance use are not established and are an urgent research question for the ISBD task force [source: Gottlieb et al. 2019].

Sources

Sources:

Further reading (not drawn on directly; details via the sources above) [uncertain]: Barbini B et al. (2005), dark therapy for mania, pilot study, Bipolar Disorders; Wehr TA et al. (1998), case report of extended darkness in rapid-cycling bipolar disorder; Henriksen TEG et al. (2016) full text; NICE CG185 and CANMAT/ISBD 2018 bipolar guidelines (not checked for dark-therapy content).

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