9 Child and adolescent psychiatry9.7 Disorders in childhood and adolescence

9.7.9 Substance misuse in young people

2 min read1 figure

Written by Resident Doctor Committee · Published

Patterns and diagnosis

  • Cannabis is the leading drug in young people, reported by 86% of under-18s in treatment in England.

  • Earlier initiation is associated with later dependence, partly through shared vulnerabilities.

  • The International Classification of Diseases, 11th revision (ICD-11), separates a harmful episode, a harmful pattern and dependence, which rests on impaired control and priority, not on quantity.

Physical harms

Substance

Harm

Nitrous oxide

Functional B12 inactivation causes myeloneuropathy despite a normal serum B12; treat with cessation and parenteral B12

Nitazenes

Highly potent opioids that contaminate heroin or counterfeit tablets; naloxone reverses them but may need repeating

Look at the bright signal on these T2-weighted images, which is confined to the posterior columns of the cervical cord: this is the pattern of the myeloneuropathy (subacute combined degeneration) caused by heavy nitrous oxide misuse, which can occur even when serum B12 is normal. Chiara Briani,1,* Chiara Dalla Torre,1 Valentina Citton,2 Renzo Manara,2,3 Sara Pompanin,1 Gianni Binotto,4 and Fausto A, CC BY-SA 3.0, via Wikimedia Commons

Assessment, consent and safeguarding

  • Explain the limits of confidentiality before taking the history.

  • Gillick competence is decision-specific: the under-16 has enough understanding and maturity for the proposed treatment.

  • Fraser guidelines apply only to contraceptive advice or treatment without parental involvement, not to all under-16 treatment.

  • County lines exploitation makes young people carry or sell drugs, money or weapons under coercion, and no single sign confirms it.

  • A child's referral to the National Referral Mechanism does not need consent, whereas an adult's generally does.

Comorbidity

  • Treat psychosis and other coexisting illness alongside substance work, without requiring abstinence first.

  • Do not withhold indicated stimulant treatment for attention deficit hyperactivity disorder (ADHD) for fear of later addiction; assess the risk of diversion instead.

Psychological treatment

Match the intervention to severity and context. Psychosocial work comes first, and medication is needed less often than in adults.

  • Motivational interviewing is the first psychological intervention for an adolescent who misuses cannabis and is ambivalent about change, when family pressure has failed.

  • Motivational work can focus on what the young person cares about, such as sleep, money, sport and relationships.

  • Family or multisystem approaches help where comorbidity or social difficulties are substantial.

  • Volatile substance (inhalant) misuse has no drug of established efficacy, so first-line treatment is a multimodal psychosocial package: individual cognitive behavioural therapy, family therapy and structured activity or engagement programmes.

Medication

  • The National Institute for Health and Care Excellence (NICE) recommends inpatient assisted alcohol withdrawal for ages 10 to 17, often using chlordiazepoxide or diazepam off-label.

  • Acamprosate and oral naltrexone are considered only at 16 to 17, after an inadequate response to psychosocial treatment.

  • No established substitution medicine treats stimulant dependence.

  • Do not impose detoxification or a fixed end date simply because of age.

Transition

  • Prepare the move to adult services before the age boundary, with named workers, clear prescribing arrangements and an agreed follow-up date.

Revision material for the MRCPsych examinations. Not clinical guidance, and not for use in patient care.