Cannabis

• Also called marijuana, gunja, yarndi, dope, pot, weed
• Commonly mixed with tobacco

Synthetic cannabis is not a cannabinoid related chemical. It may cause severe toxicity and stimulant effects — agitation, paranoia, psychosis, seizures, hyperthermia.

Effects of cannabis

• Cannabis and tobacco smoke damage lungs, reduce physical fitness
• Worse if smoked together or inhaled through water (bong)

Vulnerable populations

• Existing mental health condition — may make symptoms worse or reduce response to medicines — see Mental health emergency and Mental health assessment
• Pregnant — increased risk of low birth weight babies, risk of neonatal withdrawal syndrome — see Postnatal care of baby and Brief interventions
• Young people are at risk of greater harm — leaving school, homelessness, social vulnerabilities

Cannabis hyperemesis syndrome

• Occurs in regular daily long term user
• Causes nausea, vomiting, abdominal cramps — partially relieved by hot showers
• May be severe and cause dehydration and electrolyte disturbance
• Usually resolves in days when stop cannabis use but likely to recur if cannabis used again

Intoxication

• Relaxed, happy
• Confused or aggressive
• Reduced coordination and driving impairment
• Panic, feel anxious or paranoid (everyone is against them)
• Cannabis hyperemesis syndrome

Acute psychosis

• Have delusions (believe things that are not true), hallucinations (see or hear things that are not there), strange/disorganised thoughts or behaviour
• Symptoms usually stop soon after intoxication subsides but can have symptoms for weeks or months

Long-term health effects

• Chronic lung disease, reduced physical fitness
• Often causes problems with memory, concentration, motivation
• Decreased ability to organise and learn complex information
• Increased risk of oral issues due to dry mouth

Do

• All cannabis users should be offered help to stop — see Brief interventions
• Special effort should be made if
• History or family history of mental illness
• Pregnant or breastfeeding
• Person experiencing long-term effects on health and wellbeing

Managing cannabis cessation or withdrawal

• When person who is dependent stops or cuts down they may get withdrawal symptoms — trouble sleeping, cranky feelings, hostility
• Can start within 24 hours of stopping use. Peaks around 4–10 days, last several weeks
• May increase risk of violence, self-harm, suicide
• Can cause cannabis hyperemesis syndrome
• Cannabis users may also have tobacco dependency
• Gradual reduction of cannabis use can be effective in stopping use without need for medicine
• If pre-existing psychotic illness —  usual antipsychotic medicine may need to be adjusted

Do

• Medical consult about medicines — give until agitation settled and review daily
• Diazepam oral — adult 5–10mg/dose up to 20mg/day
• Avoid using diazepam daily for more than 1 week — may lead to tolerance/dependence
• If agitation not settled by diazepam — give olanzapine oral — adult 5–10mg/dose up to 20mg/day
• Antiemetic for nausea or vomiting — see Nausea and vomiting — check for signs of dehydration and low potassium
• Make management plan
• Refer to drug and alcohol service or mental health team for support