NeuroHabit Evidence Matrix

How to read the matrix

Each habit is graded twice, because a plausible mechanism and a proven benefit are different claims.

Mechanism evidence

How well established the link is between the habit and its named pathway, from human, animal or imaging studies.

Outcome evidence

How well established the effect is on mood, wellbeing or mental-health outcomes in people.

Grades

Strong: Meta-analyses or multiple randomised trials
Moderate: Some trials, or consistent observational and mechanistic work
Limited: Plausible, but indirect, small or animal-only evidence

From grade to score

Three tiers carry different weight. Foundational habits unlock a category's full score, secondary habits score at weight 2, and bonus habits at weight 1. Each category's foundational habits:

Dopamine

Drive & reward

Deep Work / Main Goal · Meaningful Progress · Morning Sunlight (10–15 min)

Serotonin

Stability & mood

Sleep · Solat / Daily Prayer / Mindfulness · Rhythmic Movement (20+ min)

Oxytocin

Connection & trust

Active Socialising (20+ min) · Physical Touch / Oxytocin Anchor · Sincere Appreciation (Expressed)

Endorphin

Resilience & movement

Exercise (Dedicated Session) · Active Day (Incidental Steps)

The matrix

33 habits across four pathways. Filter by category.

Habit	Tier	Mechanism	Outcome	Key literature	Notes
Deep Work / Main GoalDopamine	Foundational	Moderate	Limited	Berke 2018, Nat Neurosci; Gershman 2024	Dopamine ramps during sustained goal pursuit are well described in animal and computational work. Direct wellbeing trials of deep-work sessions are limited.
Meaningful ProgressDopamine	Foundational	Limited	Moderate	Amabile & Kramer 2011, The Progress Principle	Diary evidence links small daily progress to mood and motivation. Observational; the dopamine link is inferred.
Morning Sunlight (10–15 min)Dopamine	Foundational	Moderate	Moderate	Leproult & Van Cauter (circadian); Golden et al. 2005, Am J Psychiatry	Circadian entrainment by morning light is well established, and light therapy improves mood. The dopamine-specific pathway is less direct.
Task List CompletionDopamine	Secondary	Limited	Limited	Berridge 2007, Psychopharmacology	Small, real reward signals per completed task. Reweighted down after review: productivity gains do not map cleanly to neurochemical uplift.
Active Skill Practice (20+ min)Dopamine	Bonus	Moderate	Limited	Reference in review	Note in review
Goal-Focused JournalingDopamine	Bonus	Limited	Limited	Reference in review	Plausible prefrontal and anticipatory-reward mechanism; outcome trials for this specific habit are limited. Kept at the lowest weight.
Screen-Free Block (2+ hrs)Dopamine	Bonus	Moderate	Moderate	Hunt et al. 2018, J Soc Clin Psychol	Limiting social media use reduced loneliness and depressive symptoms in a randomised trial. Framed as a protective, removal habit.
Tyrosine-Rich MealDopamine	Bonus	Moderate	Limited	Amino-acid precursor literature	Tyrosine is the dietary precursor to dopamine. Evidence for mood outcomes from diet alone is limited.
Fasting (Eating Window)Dopamine	Secondary	Limited	Limited	Reference in review	A consistent eating window supports regular routines. Claims about dopamine receptor sensitivity are speculative and are not used in scoring rationale.
SleepSerotonin	Foundational	Strong	Strong	Scott et al. 2021, Sleep Med Rev; Zhang et al. 2024, Sleep Breath	Improving sleep improves mental health in randomised trials: the strongest causal evidence in the library. The serotonin-specific link is indirect.
Solat / Daily Prayer / MindfulnessSerotonin	Foundational	Moderate	Moderate	Goyal et al. 2014, JAMA Intern Med (47 trials, n=3,515)	Moderate evidence for anxiety and depression from meditation trials. Prayer-specific trials are fewer; the shared mechanism is stress-response downregulation.
Rhythmic Movement (20+ min)Serotonin	Foundational	Moderate	Moderate	Jacobs & Azmitia 1992, Physiol Rev	Rhythmic motor activity increases serotonergic neuron firing in animal work; walking interventions show moderate mood benefits in people.
5-a-Day (Veg & Fruit)Serotonin	Secondary	Moderate	Moderate	Jacka et al. 2017, BMC Med; Firth et al. 2019, Psychosom Med	Dietary improvement reduces depressive symptoms in trials. Note: most serotonin is made in the gut but does not cross into the brain; the link runs through the microbiome and inflammation.
Nature Walk (20+ min)Serotonin	Secondary	Moderate	Moderate	Bratman et al. 2015, PNAS	A nature walk reduced rumination and subgenual prefrontal activity versus an urban walk. Small trial; consistent with wider nature-exposure literature.
Protein-Rich MealsSerotonin	Secondary	Moderate	Limited	Tryptophan precursor literature	Tryptophan is the serotonin precursor, but protein-rich meals also raise competing amino acids, so brain entry depends on the whole meal. Mood outcomes are limited.
Gratitude / MuhasabahSerotonin	Bonus	Limited	Moderate	Davis et al. 2016, J Couns Psychol	Gratitude interventions show small but consistent wellbeing effects. The serotonin mechanism is inferred.
Breathwork / DhikrSerotonin	Bonus	Moderate	Moderate	Zaccaro et al. 2018, Front Hum Neurosci; Goyal et al. 2014	Slow breathing shifts autonomic balance toward parasympathetic activity. Effects on anxiety are modest but real.
Power Nap / Qailullah (10–25 min)Serotonin	Bonus	Moderate	Moderate	Brooks & Lack 2006, Sleep	Short naps improve alertness and mood; longer naps cause sleep inertia. Capped so it cannot substitute for night sleep.
Restorative Hobby (20+ min)Serotonin	Secondary	Limited	Moderate	Soga et al. 2017, Prev Med Rep (gardening meta-analysis)	Gardening and similar hobbies show positive wellbeing effects. Soil-bacteria serotonin findings are from animal studies only.
No Added Sugar TodaySerotonin	Bonus	Limited	Moderate	Knüppel et al. 2017, Sci Rep	Higher sugar intake is associated with later common mental disorders in cohort data. Association, not causation. Shown with a disordered-eating note.
Active Socialising (20+ min)Oxytocin	Foundational	Moderate	Strong	Holt-Lunstad et al. 2010, PLoS Med; Holt-Lunstad 2024, World Psychiatry	Social connection predicts mortality and mental health with some of the strongest evidence in behavioural science.
Physical Touch / Oxytocin AnchorOxytocin	Foundational	Moderate	Moderate	Light et al. 2005, Biol Psychol; Packheiser et al. 2024, Nat Hum Behav	Hugs and partner contact associate with higher oxytocin, and touch interventions improve wellbeing. Specific duration thresholds are not well supported, so the app says "sustained contact".
Sincere Appreciation (Expressed)Oxytocin	Foundational	Limited	Moderate	Kumar & Epley 2018, Psychol Sci	Expressing gratitude improves wellbeing for both sides, more than expressers predict. The oxytocin link is inferred.
Shared Meal (Eat Together)Oxytocin	Secondary	Limited	Limited	Dunbar 2017, Adapt Hum Behav Physiol	People who eat socially more often report closer relationships and higher life satisfaction. Cross-sectional.
Receive Care / Be VulnerableOxytocin	Secondary	Limited	Limited	Reference in review	Note in review
Group Singing / Shared MusicOxytocin	Bonus	Moderate	Limited	Pearce et al. 2015, R Soc Open Sci	Group singing speeds social bonding. The evidence points to endorphin-mediated bonding as much as oxytocin.
Community Help / Act of KindnessOxytocin	Bonus	Moderate	Moderate	Moll et al. 2006, PNAS; Curry et al. 2018, J Exp Soc Psychol	Giving activates reward circuitry, and kindness interventions show small-to-medium wellbeing effects.
Social Laughter / HumorOxytocin	Bonus	Moderate	Limited	Manninen et al. 2017, J Neurosci	Social laughter releases endogenous opioids (PET). Placed in Oxytocin because its function is bonding; moved from Endorphin after review.
Exercise (Dedicated Session)Endorphin	Foundational	Strong	Strong	Singh et al. 2023, Br J Sports Med (97 reviews, n=128,119); Boecker et al. 2008, Cereb Cortex	Exercise reduces depression and anxiety with medium effects; PET shows opioid release in running. Tiered by intensity.
Active Day (Incidental Steps)Endorphin	Foundational	Limited	Moderate	Bizzozero-Peroni et al. 2024, JAMA Netw Open	More daily steps associate with fewer depressive symptoms. Acute neurochemical effects are weaker than structured exercise.
Cold Shower / Contrast TherapyEndorphin	Secondary	Moderate	Limited	Šrámek et al. 2000, Eur J Appl Physiol; Buijze et al. 2016, PLoS One	Cold water raises noradrenaline robustly. The endorphin link is extrapolated, and the app says so. Not for people with cardiovascular conditions.
Creative Play / DancingEndorphin	Secondary	Moderate	Moderate	Tarr et al. 2016, Evol Hum Behav	Synchronised dancing raises pain thresholds, a marker of endorphin release, and increases bonding.
Yoga / Mobility / Stretching (10+ min)Endorphin	Bonus	Moderate	Moderate	Cramer et al. 2013, Depress Anxiety	Yoga shows moderate short-term benefits for depressive symptoms.

Effect size to weight

Where meta-analyses report effects on depressive symptoms, those effect sizes anchor the weights. Values are approximate standardised mean differences summarised from the cited reviews.

Domain	Effect on depression (SMD)	Weight	Tier	Rationale
Vigorous exercise (45+ min)	~0.60–0.80	3	Foundational, high level	Largest effect in the library; PET-confirmed opioid release.
Sleep (7–9 hrs)	~0.40–0.55	2	Foundational	Causal link shown in randomised trials of sleep improvement.
Moderate exercise (30 min)	~0.43	2	Foundational, moderate level	Within the WHO-recommended range; dose-response supported.
In-person social connection	~0.19–0.40	2–3	Foundational	Mortality-level evidence justifies weight despite a moderate depression effect.
Diet (fibre, protein)	~0.25–0.35	1–2	Secondary	Strong mechanism, moderate trial outcomes.
Mindfulness, breathwork, dhikr	~0.30–0.38	1	Bonus	Real but modest effects (Goyal et al. 2014).
Walking and incidental activity	~0.25–0.30	1	Bonus	Effective, but weaker than structured exercise.
Journaling, goal-writing	Indirect	1	Bonus	Plausible mechanism, insufficient outcome data.

What the review changed

The matrix is not decoration: grading the evidence changed the engine.

PromotedMorning SunlightRaised to foundational, so Dopamine no longer depends on a single habit that some users cannot do daily.

ReweightedTask List CompletionKept secondary but reduced: real but small reward signals did not justify a heavy weight.

MovedSocial LaughterFrom Endorphin to Oxytocin. Its function is bonding, even though PET shows opioid release.

SoftenedCold exposure and touch claimsCold water is credited mainly with noradrenaline, with the endorphin link marked as extrapolated; "20-second hug" became "sustained contact".

RebalancedSerotonin weightsFoundational weights reduced so one category could not dominate the daily score.

RemovedVirtual check-insWeak evidence relative to in-person contact, and overlapping with Active Socialising.

What this is, and isn't. NeuroHabit is a habit-building and psychoeducation tool, not a treatment for any condition. Mapping a habit to one neurotransmitter is a simplification: every habit here acts on several systems at once.

The grades reflect the literature as reviewed in October 2026 and will change as evidence does.