Adult ADHD assessment and management: childhood onset, differentials, stimulants, Queensland PBS rules and cannabis risk
A GP-facing summary of the ADHD half of a Nova Mentis Clinic education forum — how to structure an adult assessment, when to refer, first-line stimulants and monitoring, PBS nuances for long-acting agents in Queensland, and why medical cannabis is not an ADHD treatment.
- Primary speakers
- Dr Kartika Johnson (consultant psychiatrist, Nova Mentis Clinic) — adult ADHD assessment. Dr Sanoop Jacob Mammon (consultant psychiatrist, Nova Mentis Clinic) — management, stimulants, PBS and safety. Hosted by Fran (Nova Mentis). Sponsor talks (finance) omitted from this clinical summary.
- Session context
- Otter id
BbaQU-wlxh_fXPabpFy8sdLI9bs· title ADHD Assessment and Management · ~82 min (4934 s) · recorded 2026-09-19. Forum also covered depression/psychosis later the same evening (separate Otter note). ASR is imperfect — drug names and doses should be checked against current PBS / product info before prescribing.
Key messages for GPs
- ADHD diagnosis needs core symptoms + childhood onset (before 12) + impairment in ≥2 settings + no better alternate explanation — not a TikTok checklist or a friend’s Ritalin trial.
- Ask open childhood questions (“What did teachers say?”) rather than yes/no symptom lists; school reports and parent/sibling collateral help, especially for PBS long-acting pathways.
- Treat “can’t concentrate” as a symptom: screen depression, anxiety, sleep/OSA, thyroid, substances, learning disability/ASD before jumping to ADHD.
- After diagnosis: baseline BP, pulse, weight; cardiac history; consider ECG if starting stimulants; urine drug screen when comorbidity suspected — then skills and organisation strategies before (or alongside) meds.
- Medical cannabis is not an established ADHD treatment; THC plus stimulants was framed as substantially raising psychosis risk. Check QScript before you prescribe.
Assessment: four questions
Dr Johnson framed ADHD as a neurodevelopmental condition: inattentive, hyperactive-impulsive, or combined. Prevalence cited: roughly 6–8% of Australian children and 3–5% of adults (>1 million Australians). Girls/women are more often inattentive and under-recognised until adulthood.
Common reasons people ask for assessment: relative diagnosed; “tried a friend’s stimulant and my head went quiet”; promotion / parenting / university load unmasking compensatory strategies; treatment-resistant depression/anxiety; psychologist suggestion; menopausal “brain fog”.
None of those alone prove ADHD. Work through: (1) enough DSM-style core symptoms; (2) primary-school-era onset, not only high school; (3) functional impairment across settings for ≥6 months; (4) alternate explanations. Useful tools mentioned: ASRS screen, Adult ADHD Quality of Life scale, SNAP-IV / Conners with family; school reports. Prefer open childhood probes over leading yes/no questions.
Differentials and when to refer
- Depression, anxiety/panic, chronic sleep deprivation / OSA, pain meds, thyroid disease, intoxication or withdrawal, learning disability, intellectual disability, ASD.
- In midlife women: consider menopausal cognitive change / HRT trial discussion before locking in ADHD.
- Refer psychiatry when you are uncomfortable doing the assessment; collateral is weak; complex comorbidity (bipolar, psychosis, significant substance use, eating disorder); poor response or severe adverse effects on stimulants; pregnancy/breastfeeding planning; physical illness making stimulants uncertain.
Why you suspect ADHD and your evidence; psych and medical history; meds; substances/rehab; recent ECG/labs; prior ADHD treatment; and explicitly whether you want diagnosis+plan only or ongoing shared care (who prescribes, who monitors).
Non-drug strategies first
Dr Mammon: diagnosis does not equal immediate stimulant. Explain ADHD; pick one target problem (e.g. household routines) as the gauge of improvement; involve a partner if agreeable. Practical skills: break tasks into chunks, short timers with breaks, declutter workspace, consistent sleep/meals, batch emails, protect deep-work blocks. Patients often demand a “quick fix” after social media — hold the line on skills and safety workup.
Stimulants, alternatives and monitoring
Baseline before meds: BP, pulse, weight; cardiac and family cardiac history; sleep, mood, alcohol/drugs; current meds/interactions. ECG not mandated for every patient but commonly done before stimulants; cardiology clearance if symptoms or significant history. Bloods for mimics; UDS when substance comorbidity is plausible.
Stimulants (methylphenidate; dexamfetamine / lisdexamfetamine) are first-line when suitable. Alternatives discussed: atomoxetine (inattention-leaning; watch interactions, LFTs); guanfacine/clonidine (α2 agonists — adult ADHD not PBS first-line; BP/postural effects). Mechanism sketch: increase prefrontal dopamine/norepinephrine tone via different pathways.
Stimulant adverse effects to monitor: appetite/weight loss (caution in eating disorders), insomnia, headache (often at trough), anxiety/panic early or on escalation, palpitations; stop and reassess if mania/psychosis emerges. Titration examples in the talk (confirm current product info): IR methylphenidate often started ~5 mg morning/afternoon; IR dexamfetamine in 5 mg steps; long-acting options after establishing daily need — Ritalin LA vs Concerta release profiles differ for evening bleed and sleep.
Queensland PBS notes from the talk
| Agent / class | Point made in the forum |
|---|---|
| Immediate-release stimulants | GPs in Queensland can prescribe IR in appropriate cases |
| Lisdexamfetamine (Vyvanse) / some LA methylphenidate | May need retrospective childhood diagnosis with collateral (parent, school reports, teacher) — not patient recall alone |
| Concerta and atomoxetine (adult PBS) | Described as needing documented childhood diagnosis by a paediatrician (treated as a child) — not retrospective-only pathway |
| Guanfacine / clonidine in adults | Generally private / not adult ADHD PBS first-line as framed |
PBS authority rules change. Treat the above as speakers’ clinical teaching on the night — confirm current Queensland PBS / QScript requirements yourself.
Medical cannabis and stimulants
Patients often ask for cannabis for ADHD after social media. Speakers: one small 2017 vapourised-THC signal was not replicated; a large 2021 meta-analysis (~1580 patients) found small–moderate cognitive impairment from THC across executive function, working memory, learning and attention. Clinically they often pause ADHD assessment until THC is stopped and UDS is clean — cannabis may quiet anxiety/sleep without treating core ADHD.
THC + stimulant was described as markedly increasing psychosis risk (figures up to ~tenfold cited in talk). CBD-only products were framed as relatively safer but still warrant closer review. Check QScript — interstate/telehealth cannabis scripts are easy to miss.
Shared care and Q&A highlights
- Clear who initiates, who titrates, who writes ongoing scripts; max dose before re-referring; safe storage / no diversion; both parties check QScript to avoid double-dipping.
- Routine stress echo for a healthy patient on stimulants was called out as usually unnecessary without cardiac indication.
- Psychologist ADHD reports: acknowledge but complete medical/psych/substance workup before meds — DIVA alone is not a full prescribing assessment.
- Vyvanse + top-up IR dexamfetamine can be reasonable for morning cognitive load, but stay within a sensible combined amfetamine load (speaker comfort threshold discussed around Vyvanse 70 mg + limited IR top-up — confirm locally).
- Lamotrigine: may help emotional dysregulation / bipolar-spectrum comorbidity — not a core ADHD treatment.
- If a psychiatrist letter says “GP to prescribe” but QScript shows THC and you are uncomfortable — you may decline, request review, or seek another opinion; governance still sits with the prescriber.