Overview
Definition:
A first psychotic episode in a child or adolescent is the initial presentation of symptoms of psychosis, characterized by a loss of contact with reality
This can be triggered by substance use, such as cannabis, or represent the onset of a primary psychiatric disorder like schizophrenia spectrum disorders or bipolar disorder
Differentiating these etiologies is critical for appropriate management and prognosis.
Epidemiology:
While primary psychotic disorders are rare in prepubertal children, their incidence increases significantly during adolescence
Cannabis use is prevalent among adolescents, and its association with psychosis is a growing concern
Studies suggest a dose-dependent relationship between cannabis potency and the risk of psychosis
Differentiating is challenging as symptoms can overlap significantly.
Clinical Significance:
Accurate diagnosis is paramount as the management, prognosis, and long-term outcomes differ drastically between cannabis-induced psychosis and primary psychotic disorders
Misdiagnosis can lead to delayed or inappropriate treatment, potentially exacerbating symptoms, increasing risk of harm, and negatively impacting neurodevelopmental trajectories
Early intervention is key for improving functional recovery.
Clinical Presentation
Symptoms:
Hallucinations (auditory, visual, tactile, olfactory)
Delusions (persecutory, grandiose, referential)
Disorganized speech or thought
Disorganized or catatonic behavior
Negative symptoms (avolition, alogia, affect flattening)
Agitation or aggression
Paranoia
Social withdrawal
Deterioration in academic or social functioning
Potential history of recent cannabis use, including frequency, potency (THC content), and last use.
Signs:
Unusual affect or emotional responses
Poor eye contact
Poor hygiene
Disheveled appearance
Difficulty with attention or concentration
Psychomotor abnormalities (agitation, retardation)
Evidence of substance intoxication (e.g., conjunctival injection, dry mouth, increased heart rate) may be present with cannabis-induced psychosis.
Diagnostic Criteria:
DSM-5 criteria for schizophrenia spectrum and other psychotic disorders
DSM-5 criteria for substance/medication-induced psychotic disorder
Key distinction involves the temporal relationship between substance use and psychotic symptoms, the nature of the symptoms, and the duration of the psychosis after significant cessation of the substance
Primary psychosis typically persists beyond the acute intoxication period or withdrawal syndrome.
Diagnostic Approach
History Taking:
Detailed collateral history from parents/guardians is essential
Assess onset, duration, and nature of psychotic symptoms
Inquire about prior psychiatric history, family psychiatric history, developmental milestones, academic performance, and social functioning
Crucially, obtain a thorough substance use history, including type of substance (cannabis, other drugs), frequency, amount, THC potency, age of initiation, and patterns of use
Screen for co-occurring mental health conditions
Rule out medical causes for psychosis.
Physical Examination:
A comprehensive physical examination to rule out medical causes of psychosis
Assess vital signs, neurological status (including cranial nerves, motor function, sensation, coordination, and reflexes), and signs of substance intoxication or withdrawal
Look for any evidence of self-harm or harm to others
Thorough mental status examination focusing on thought content, perception, affect, insight, and judgment.
Investigations:
Laboratory tests: Complete blood count (CBC), electrolytes, liver function tests (LFTs), renal function tests (RFTs), thyroid function tests (TFTs), vitamin B12 and folate levels, urine drug screen (UDS) for cannabis and other substances
Imaging: MRI brain to rule out structural lesions (e.g., tumors, hydrocephalus) or inflammatory processes
Electroencephalogram (EEG) if seizures are suspected
Consider cerebrospinal fluid (CSF) analysis if meningitis or encephalitis is suspected.
Differential Diagnosis:
Cannabis-induced psychotic disorder
Schizophrenia
Schizoaffective disorder
Brief psychotic disorder
Delusional disorder
Bipolar disorder (manic or depressive episode with psychotic features)
Major depressive disorder with psychotic features
Substance intoxication or withdrawal (other substances)
Medical conditions (e.g., autoimmune encephalitis, infectious causes, metabolic disturbances, endocrine disorders, neurological conditions)
Medication side effects.
Management
Initial Management:
Ensure patient safety and safety of others
Hospitalization may be required for stabilization, risk assessment, and intensive treatment
Initiate supportive care and establish rapport
Medical workup to rule out organic causes
Discontinue offending substances if identified and confirm cessation
Close monitoring for symptom exacerbation or adverse events.
Medical Management:
Antipsychotic medications are the mainstay for managing psychotic symptoms
For cannabis-induced psychosis, short-term use may suffice with resolution upon cessation
For primary psychosis, longer-term treatment is typically required
First-generation antipsychotics (e.g., haloperidol, chlorpromazine) or second-generation antipsychotics (e.g., risperidone, olanzapine, quetiapine, aripiprazole) can be used
Dosing should be cautious in pediatric populations, starting low and titrating slowly
For cannabis-induced psychosis, symptom resolution may occur within days to weeks after cessation, often without the need for long-term antipsychotic treatment
For primary psychosis, antipsychotics are continued to manage symptoms and prevent relapse.
Pharmacological Treatment:
Antipsychotic medications: Risperidone (0.5-3 mg/day), Olanzapine (2.5-10 mg/day), Quetiapine (50-400 mg/day), Aripiprazole (2-15 mg/day)
Doses are highly individualized and require careful titration
Antiemetics may be used for nausea if present
Benzodiazepines may be used cautiously for agitation but can sometimes worsen disorganization.
Supportive Care:
Psychosocial interventions are critical
Individual psychotherapy (e.g., cognitive behavioral therapy for psychosis - CBTp), family therapy, and psychoeducation for the patient and family
Social skills training and vocational rehabilitation may be beneficial
Support groups for patients and families
Nutritional support and regular monitoring of physical health are also important.
Complications
Early Complications:
Aggravation of symptoms, self-harm, harm to others, treatment non-adherence, adverse effects of medication (e.g., extrapyramidal symptoms, sedation, metabolic changes).
Late Complications:
Development of a chronic psychotic disorder, functional impairment (academic, social, occupational), substance use relapse, increased risk of suicide, social stigma, long-term medication side effects.
Prevention Strategies:
Early identification and intervention
Comprehensive psychoeducation regarding substance use and its risks
Development of coping mechanisms and relapse prevention plans
Regular psychiatric follow-up
Addressing co-occurring mental health conditions and family stressors.
Prognosis
Factors Affecting Prognosis:
Early intervention, adherence to treatment, presence of supportive family and social environment, severity of initial symptoms, presence of co-occurring disorders, cannabis potency and frequency of use, and specific diagnosis (primary vs
substance-induced).
Outcomes:
Cannabis-induced psychosis often has a better prognosis with complete resolution of symptoms if cannabis use is ceased promptly
Primary psychotic disorders have a more variable prognosis, with a significant proportion experiencing chronic symptoms and functional impairment, though early treatment can improve outcomes and facilitate recovery.
Follow Up:
Long-term follow-up is essential for all individuals presenting with a first psychotic episode
This includes regular psychiatric assessments, medication monitoring, psychosocial support, and ongoing assessment for substance use
The frequency of follow-up will depend on the diagnosis and treatment response, typically continuing for several years.
Key Points
Exam Focus:
The key differentiator between cannabis-induced psychosis and primary psychosis is the temporal relationship to cannabis use and symptom persistence after cessation
High potency cannabis (high THC) is associated with increased risk
Differentiating requires thorough history, including collateral, and comprehensive workup.
Clinical Pearls:
Always suspect and screen for substance use in adolescents presenting with new-onset psychosis
Remember that even if cannabis is identified, it does not exclude a primary psychotic disorder
A detailed family history is crucial for risk assessment
Involve parents/guardians extensively in the diagnostic and management process.
Common Mistakes:
Attributing all psychotic symptoms in adolescents to cannabis without a thorough workup for primary psychiatric disorders or medical causes
Underestimating the potency of modern cannabis products
Failing to obtain collateral history from caregivers
Initiating long-term antipsychotic treatment without adequate assessment and follow-up for potential cannabis-induced psychosis.