Psychotic Features in a Teenager

Clinical Scenario

Eric Knowles is 17 years old. His father calls with concerns about behavioural changes over the past 3-4 weeks. Eric has become increasingly withdrawn, suspicious, and has been talking about people watching him and reading his thoughts. His father has overheard him talking to himself and is worried Eric is hearing voices. Eric has become aggressive toward his younger brother Daniel. He has been smoking cannabis regularly for the past 6 months. There is a family history of schizophrenia (paternal grandfather and aunt). Eric is refusing to see a doctor.

What This Case Tests

Taking a psychiatric history through a third party (father); assessing psychotic symptoms remotely (hallucinations, delusions, thought disorder); conducting a risk assessment covering self-harm, harm to others, and vulnerability; understanding the cannabis-psychosis relationship; initiating an urgent CAMHS referral; managing a patient who refuses to engage with services; safeguarding the younger sibling.

Common Mistakes Trainees Make

The three most common mistakes are: failing to conduct a thorough risk assessment (Eric has been aggressive toward his brother, has paranoid ideation, and may have access to means of harm), not recognising the safeguarding concern for Daniel (who is living with an increasingly aggressive and psychotic older brother), and treating this as a routine mental health referral rather than the psychiatric emergency it is — acute psychosis in a teenager requires same-day or urgent CAMHS referral, not a routine waiting list.

The Consultation Challenge

This is one of the most complex cases in the Child Health bank. A 17-year-old with acute psychotic features, cannabis use, family history of schizophrenia, aggression toward a sibling, and refusal to see a doctor — every element adds a layer of clinical and ethical complexity.

The father is frightened. His son is changing in front of his eyes, and the family history of schizophrenia makes his worst fear specific and terrifying. Start by acknowledging this: "I can hear how worried you are, and I want you to know you've done the right thing calling us. What you're describing sounds serious, and I'm going to help you get the right support for Eric."

Take a structured psychiatric history through the father. This is indirect assessment, so you need to be systematic. Ask about: timeline (when did changes start, was the onset gradual or sudden), perceptual disturbances (does Eric appear to be hearing or seeing things others cannot? What has the father observed?), paranoid ideation (what specific beliefs has Eric expressed? Who does he think is watching him?), thought disorder (is his speech making sense? Is he coherent?), social withdrawal (has he stopped attending school, seeing friends?), substance use (cannabis frequency, amount, any other substances), and mood (has there been a low mood component?).

Risk assessment is non-negotiable. Cover: self-harm and suicide (any expressions of hopelessness, passive or active ideation), harm to others (the aggression toward Daniel — how severe? Physical threats or actual violence?), and vulnerability (Eric is refusing medical help while acutely unwell, and he may be at risk of exploitation). Ask specifically about access to means of harm in the home.

The safeguarding element is critical. Daniel is living with an increasingly aggressive, psychotic older brother. You have a duty to assess Daniel's safety and consider whether a safeguarding referral or at minimum a safety plan for the family is needed. Ask the father: "Is Daniel safe at home? Has Eric actually hurt him, or is it verbal threats? What arrangements can you make to keep Daniel safe?"

Management is urgent. This is not a routine CAMHS referral. Acute psychosis in a teenager requires same-day crisis CAMHS referral, or if Eric is at immediate risk, consideration of A&E attendance. The challenge is that Eric is refusing to see anyone. Explain to the father that CAMHS crisis teams can visit at home, that engagement with reluctant patients is part of their expertise, and that in extreme circumstances, the Mental Health Act allows assessment without consent if there is serious risk.

Explain the cannabis-psychosis relationship honestly. Cannabis use — particularly in adolescents with a genetic predisposition — can trigger psychotic episodes. This may resolve with cessation, or it may have unmasked an underlying vulnerability. The specialist assessment will clarify this.

Time check: Spend the first 4 minutes on the psychiatric history through the father. Complete the risk assessment by minute 7 — this cannot be rushed. Address the safeguarding concern for Daniel between minutes 8-9. Use the remaining time for the urgent CAMHS referral, home safety planning, and managing Eric's refusal to engage.

How Examiners Mark This Case

Data Gathering and Diagnosis: Examiners assess whether you take a structured psychiatric history despite the information being second-hand. They look for systematic assessment of psychotic symptoms (hallucinations, delusions, thought disorder), timeline and onset pattern, substance use history, family psychiatric history, and a thorough risk assessment covering self-harm, harm to others (Daniel), and vulnerability. They also assess whether you screen for organic causes (although unlikely at 17, drug-induced psychosis versus primary psychotic disorder is an important distinction).

Clinical Management and Medical Complexity: This is heavily weighted. Examiners expect you to recognise this as a psychiatric emergency requiring same-day crisis CAMHS referral (not routine referral). They look for knowledge of the crisis pathway, home-based assessment options, the Mental Health Act provisions for young people who refuse assessment, and immediate safety planning for the family. Understanding the cannabis-psychosis relationship (trigger, unmask, or cause) and the significance of the family history demonstrates clinical depth.

Relating to Others: Examiners assess whether you support the father through what is an extremely frightening situation, whether you address Daniel's safety proactively, whether you explain the next steps clearly and with compassion, and whether you provide a concrete plan for what to do if Eric deteriorates before CAMHS responds. The father should leave the consultation knowing exactly what will happen next and what to do in an emergency.

Example Opening

Strong opening: "Thank you for calling — I can hear how worried you are, and I want you to know that what you're describing sounds like it needs urgent attention. You've absolutely done the right thing contacting us. I need to ask you some detailed questions about Eric so I can get the right help in place as quickly as possible."

This immediately validates the father's decision to call, signals urgency without causing panic, and sets the expectation for a structured assessment.

When discussing the refusal: "I understand Eric doesn't want to see a doctor, and that's actually quite common when someone is experiencing these kinds of symptoms. The crisis mental health team are very experienced at engaging young people who are reluctant. They can come to your home, and their approach is gentle and skilled. If Eric is at serious risk and continues to refuse, there are legal frameworks that allow us to ensure he gets the help he needs — but let's try the voluntary route first."

Avoid: "If he doesn't want to come in, there's not much we can do." (Clinically wrong and potentially dangerous).

How This Appears in the SCA

Acute psychosis in a young person is a high-stakes SCA case that tests your ability to manage a psychiatric emergency from primary care. The examiner assesses whether you recognise the urgency, conduct an adequate risk assessment through a third party, address the safeguarding dimension, and initiate appropriate crisis referral. This case combines clinical psychiatry with safeguarding, consent, and family dynamics.

Key Statistic

Cannabis use in adolescence is associated with a 2-4 fold increased risk of developing psychotic disorders, with the risk further elevated by genetic vulnerability (family history of schizophrenia). The average duration of untreated psychosis in young people is 12-24 months, and shorter duration of untreated psychosis is associated with better long-term outcomes.

Relevant Guidelines

• NICE CG155: Psychosis and schizophrenia in children and young people
• NICE CG185: Bipolar disorder — assessment and management
• NICE guidelines on cannabis and psychosis risk in young people.

Frequently Asked Questions

How do I assess psychotic symptoms through a third party in the SCA?

Ask the father to describe specific observable behaviours rather than interpretations. "What exactly has Eric said about people watching him? Can you describe what it looks like when he seems to be hearing voices? Has his speech changed — is he making sense?" Observational data from family members is clinically valuable for psychotic presentations. Ask for specific quotes and descriptions rather than summaries.

What is the relationship between cannabis and psychosis in young people?

Cannabis use in adolescence increases psychotic disorder risk by 2-4 fold, with higher risk from stronger strains (high THC, low CBD) and earlier onset of use. In individuals with genetic vulnerability (family history of schizophrenia), the risk is further elevated. Cannabis can trigger a psychotic episode that resolves with cessation, unmask an underlying vulnerability that then runs an independent course, or exacerbate existing psychotic illness. The specialist assessment will help differentiate these scenarios.

When should I consider using the Mental Health Act for a teenager?

The Mental Health Act applies to people of all ages. If Eric is at serious risk to himself or others and is refusing voluntary assessment, a Section 135 warrant can be obtained for police to enter the home and take him to a place of safety, or a Mental Health Act assessment can be arranged. However, this is a last resort — explain to the father that CAMHS crisis teams are skilled at engaging reluctant young people, and voluntary engagement is always preferred. Knowledge of this framework demonstrates clinical maturity without suggesting it as a first-line intervention.

What safeguarding considerations are there for Eric's younger brother?

Daniel is living with a sibling who has become aggressive and unpredictable due to psychotic symptoms. This creates a safeguarding concern that you must address. Ask the father about the nature and severity of the aggression (verbal versus physical), whether Daniel has been harmed, and what arrangements can be made to keep Daniel safe. Consider whether a safeguarding referral to children's social care is appropriate. At minimum, create a safety plan: Daniel should not be left alone with Eric, and the father should have a clear plan for emergency situations.

How urgent is the CAMHS referral in this case?

This requires same-day crisis referral, not routine referral. Acute psychosis in a teenager with risk features (aggression, paranoid ideation, cannabis use, family history) is a psychiatric emergency. Contact your local CAMHS crisis team directly by phone to arrange urgent assessment — do not rely on a written referral through standard channels. If the crisis team cannot assess within 24 hours and the situation is deteriorating, advise the father to take Eric to A&E or call 999 if there is immediate risk of harm.