Psychotic man threatening a neighbour: capacity and involuntary assessment
A 28-year-old man with a diagnosis of paranoid schizophrenia is brought to the emergency department by police after he threatened a neighbour with a kitchen knife. He believes the neighbour has been poisoning his food and says he acted to 'defend himself'. He stopped olanzapine 3 weeks ago because he felt well. In the department he is agitated, pacing and not sleeping. He says, 'I am not sick and I don't need treatment.' He has no thoughts of self-harm. His mother is present and is worried about the neighbour's safety. The psychiatric unit has a bed but the on-call psychiatrist is 45 minutes away. The emergency physician asks you to assess him.
1. How would you assess his decision-making capacity to refuse treatment, and what is your conclusion?
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- Capacity is decision-specific. Assess whether he can understand the diagnosis and proposed treatment, retain the information, weigh the risks and benefits, and communicate a choice.
- He can communicate, but his paranoid delusions (neighbour poisoning food) and lack of insight mean he cannot weigh the risk of untreated psychosis or the benefit of medication.
- Conclusion: he lacks capacity to refuse antipsychotic treatment and admission at this time. Reassess when calmer; capacity may fluctuate.
- Document the assessment and involve his mother, but capacity is his, not hers.
2. What legal framework in Hong Kong allows involuntary assessment and treatment, and what steps would you take?
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- In Hong Kong, the Mental Health Ordinance (Cap 136) allows detention for assessment and treatment when a person has a mental disorder and there is risk to self or others, or the person needs assessment and treatment.
- Arrange urgent psychiatric assessment; the on-call psychiatrist should complete the prescribed forms. If delay risks harm, use the Ordinance to detain him for assessment.
- Police have powers to remove a person to a place of safety when there is immediate risk.
- Use the least restrictive option; document the legal basis, risk assessment and involvement of family/social worker.
- Consider disclosing the minimum necessary information to the neighbour/police if there is a serious threat, balancing confidentiality.
3. How would you manage his acute agitation and risk to others in the emergency department?
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- Ensure staff safety: remove the knife if still present, call security/police, use a quiet room and verbal de-escalation.
- If imminent violence, rapid tranquillisation: IM olanzapine 10 mg or IM haloperidol 5 mg plus lorazepam 2 mg, with monitoring. Avoid combining IM olanzapine with parenteral benzodiazepine because of cardiorespiratory risk.
- Look for medical causes: infection, drug withdrawal, head injury, hypoglycaemia.
- Admit to the psychiatric unit once detained; restart antipsychotic treatment and monitor.
- Inform the police and document the risk to the neighbour.