Dr John Flett • The Assessment Centre
Medication Normalises Brain Structure in Children with ADHD
ABCD Study • 6,653 children aged 9–11 • 21 centres across the United States
Brain Structure Comparison — Three Groups
Unmedicated ADHD
Medicated ADHD (stimulant)
Typically Developing Children
Right Insula — Cortical Thickness
Brain region controlling attention switching & saliency detection
2.96
3.08
3.07
Unmedicated
ADHD
ADHD
Medicated
ADHD
ADHD
Typical
Children
Children
What this means: The unmedicated group showed measurably thinner cortex in the attention-switching region. The medicated group? Indistinguishable from typically developing children.
Left Nucleus Accumbens — Volume
Brain region controlling reward processing & motivation
522
564
560
Unmedicated
ADHD
ADHD
Medicated
ADHD
ADHD
Typical
Children
Children
What this means: The reward centre was significantly smaller in unmedicated children. With stimulant medication, the volume normalised to match typical brain development.
Source: Wu F, Zhang W, Ji W et al. (2024). “Stimulant medications in children with ADHD normalize the structure of brain regions associated with attention and reward.” Neuropsychopharmacology, 49, 1330–1340. Data from the Adolescent Brain Cognitive Development (ABCD) Study. Open access: PMC11224385. Figures recreated from published statistical data for educational purposes.
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Guiding Little Minds · Unlocking BIG Futures
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Dr John Flett • The Assessment Centre
Medication Reduces Real-World Risks Beyond the Classroom
BMJ Swedish Register Study • 148,581 people with ADHD • 2-year follow-up • Published August 2025
Risk Reduction with Continuous ADHD Medication Treatment
Suicidal behaviour
Without medication
17% lower with medication ↓
Substance misuse
Without medication
15% lower with medication ↓
Criminal behaviour
Without medication
13% lower with medication ↓
Transport accidents
Without medication
12% lower with medication ↓
For People With Recurring Problems — Even Greater Reductions
↓25%
Substance misuse
(recurring)
(recurring)
↓25%
Criminal behaviour
(recurring)
(recurring)
↓16%
Transport accidents
(recurring)
(recurring)
↓15%
Suicidal behaviour
(recurring)
(recurring)
Key insight for parents: These risks don’t happen at school desks. They happen on weekends, during holidays, at parties, while driving. The times parents are most likely to skip medication are the times the safety benefit matters most.
Source: Zhang L, Zhu N, Sjölander A et al. (2025). “ADHD drug treatment and risk of suicidal behaviours, substance misuse, accidental injuries, transport accidents, and criminality: emulation of target trials.” The BMJ, 390:e083658. Swedish national registers, 2007–2020. Figures recreated from published data for educational purposes.
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Guiding Little Minds · Unlocking BIG Futures
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Dr John Flett • The Assessment Centre
Why “School Days Only” Medication Backfires
The evidence against weekend drug holidays — and what continuous treatment protects
The Weekend Roller-Coaster Effect
MON
Adjusting
again
again
😣
TUE
Settling
in
in
😐
WED
Good
day
day
😊
THU
Good
day
day
😊
FRI
Stable
at last
at last
😊
SAT
Rebound
crash
crash
😤
SUN
No
support
support
😫
↻ This cycle repeats every week. The body never fully stabilises.
What Weekend Breaks Produce
✗ Symptom rebound (often worse than baseline)
✗ Side effects restart every Monday
✗ Monday consistently worst school day
✗ Increased family conflict on weekends
✗ Loss of neuroprotective brain benefits
✗ Body never accommodates to medication
✗ Side effects restart every Monday
✗ Monday consistently worst school day
✗ Increased family conflict on weekends
✗ Loss of neuroprotective brain benefits
✗ Body never accommodates to medication
What Continuous Treatment Provides
✓ Stable medication levels — no roller-coaster
✓ Side effects diminish over first months
✓ Consistent school performance all week
✓ Better weekends for the whole family
✓ Brain development support (neuroprotective)
✓ Social skills develop on weekends too
✓ Side effects diminish over first months
✓ Consistent school performance all week
✓ Better weekends for the whole family
✓ Brain development support (neuroprotective)
✓ Social skills develop on weekends too
ADHD Doesn’t Stop at the School Gate
When Do ADHD Difficulties Peak?
European parent survey — parents rated all times of day
Morning
Moderate
School day
High
After school
HIGHEST ★
Evening
HIGHEST ★
Bedtime
Very High
The surprise finding: Parents rated after-school and evening as more challenging than the school day itself. Homework, siblings, family meals, bedtime — all peak difficulty times. These happen every day including weekends.
What Weekend Medication Supports
Social skills
Playdates, sports, friendships
Playdates, sports, friendships
Family harmony
Meals, outings, sibling peace
Meals, outings, sibling peace
Safety
Sport, cycling, swimming, play
Sport, cycling, swimming, play
Brain development
Consistent neuroprotection
Consistent neuroprotection
Sources: Coghill R et al. (2008). “Impact of ADHD on the patient and family.” European Child & Adolescent Psychiatry, 17(Suppl 1), 2–11. Ibrahim K & Donyai P (2015). “Drug holidays from ADHD medication.” J Attention Disorders, 19(7), 551–568. Hechtman L (2021). World Congress on ADHD. Weekly cycle graphic based on published clinical patterns.
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Guiding Little Minds · Unlocking BIG Futures
Slide 3 of 3