Scope & clinical importance

Cannabis is one of the most commonly used psychoactive substances worldwide. While many users do not develop problems, a substantial minority experience impaired functioning, mood and cognition, cannabis dependence, or cannabis‑induced psychosis. Early identification allows brief interventions, relapse prevention and referral to specialist care when needed.

Patterns of problematic use

• Frequent daily or near‑daily use, especially of high‑potency products (high THC/low CBD).
• Using to cope with stress, anxiety, sleep or emotional distress rather than recreationally.
• Tolerance, unsuccessful attempts to cut down, and prioritising use over responsibilities.
• Polysubstance use (alcohol, stimulants, benzodiazepines) and use starting in adolescence increases risk of CUD.

Recognition — history, examination & screening

1. Ask non‑judgementally about frequency, amount, product type (smoked/vaped/edibles), age of onset, and reasons for use.
2. Screen for DSM‑5 criteria for Cannabis Use Disorder: impaired control, social impairment, risky use, pharmacological criteria (tolerance/withdrawal).
3. Assess psychiatric comorbidity: anxiety, depression, psychotic symptoms—ask about hallucinations, paranoia, and suicidal ideation.
4. Examine for cognitive impairment, slowed reaction time, conjunctival injection, and signs of other substance use; check driving safety and occupational impact.

Risks & harms

• Impaired attention, memory and psychomotor skills — impacts education, employment and driving safety.
• Increased risk of anxiety, depression and, in vulnerable individuals, cannabis‑induced psychosis.
• Dependence with withdrawal symptoms (irritability, sleep disturbance, decreased appetite, anxiety, craving).
• Adolescents: disruption of neurodevelopment, poorer academic outcomes and higher risk of other substance use.

Management principles

• Use brief motivational approaches in primary care (SBIRT: Screening, Brief Intervention, Referral to Treatment) to enhance readiness to change.
• Target goal collaboratively — reduction in use, abstinence, or safer patterns — depending on patient priorities.
• Prefer psychosocial evidence‑based treatments: motivational interviewing (MI), cognitive behavioural therapy (CBT), and contingency management where available.
• Consider comorbid psychiatric treatment (SSRIs, CBT for anxiety/depression) when indicated; treat psychosis urgently if present.

Withdrawal management

• Cannabis withdrawal is self‑limited but distressing for many — common symptoms include irritability, sleep problems, decreased appetite and dysphoria lasting 1–2 weeks.
• Provide psychoeducation, sleep hygiene, short‑term symptomatic treatments (e.g., melatonin or short course hypnotics only if necessary) and behavioural support.
• There is limited evidence for pharmacotherapies; consider gabapentin, nabilone or topiramate only in specialist settings and weigh risks/benefits.
• Severe withdrawal or coexisting severe psychiatric illness may require brief inpatient care and specialist addiction psychiatry input.

Managing acute intoxication

• Most intoxications are managed with reassurance, a calm environment and observation until effects subside.
• Severe anxiety, panic or psychotic symptoms may require short‑term benzodiazepine administration and psychiatric assessment.
• Monitor for concomitant substance intoxication (alcohol, stimulants) which may complicate management.

Treatment pathways & referral

• Primary care: screening, brief intervention, relapse‑prevention planning, and structured psychosocial therapy or referral to community programmes.
• Specialist addiction services: for moderate‑to‑severe CUD, poly‑substance use, repeated treatment failures, or when pharmacological trials are contemplated.
• Mental health services: urgent referral for psychosis, severe mood disorders, suicidal risk, or complex comorbidity.

Harm reduction strategies

• Reduce frequency and potency: encourage lower‑THC or CBD‑rich products if use continues, and avoid high‑risk modes (edibles in inexperienced users).
• Delay initiation in adolescents, counsel caregivers and schools; emphasise driving impairment — advise no driving for at least 24 hours after use.
• Offer smoking‑cessation support if cannabis is smoked (nicotine replacement therapies and behavioural support) and safer vaping guidance when relevant.
• Provide naloxone if concurrent opioid risk exists and integrate broader harm‑reduction services for polysubstance users.

Key takeaways

• Screen routinely for cannabis use and assess for DSM‑5 Cannabis Use Disorder criteria.
• Use brief motivational techniques and evidence‑based psychosocial treatments (CBT, contingency management) as first‑line interventions.
• Withdrawal is usually self‑limited; provide supportive care and treat comorbid psychiatric conditions actively.
• Escalate care for psychosis, severe mood disorders, suicidal risk or complex polysubstance dependence and prioritise youth prevention efforts.