Signs and Symptoms of Schizophrenia
Schizophrenia is diagnosed by the presence of at least two core psychotic symptoms (delusions, hallucinations, disorganized speech, grossly disorganized or catatonic behavior, or negative symptoms) present for a significant period during a 1-month timeframe, with overall disturbance lasting at least 6 months, accompanied by marked social or occupational dysfunction. 1
Core Psychotic Symptoms (Active Phase)
The hallmark features require at least two of the following present for a significant period during a 1-month period: 1
Delusions: Fixed false beliefs that are less complex and systematic in children and adolescents compared to adults 1, 2. Only one symptom is needed if delusions are bizarre 1, 3
Hallucinations: Auditory hallucinations are the most consistently found symptom across all ages 1, 2, 4, 5. Only one symptom is needed if hallucinations include a voice providing running commentary on the person's behavior/thinking, or two or more voices conversing with each other 1, 3
Disorganized speech: Characterized by loose associations, illogical thinking, impaired discourse abilities, tangentiality, and circumferentiality 1, 6, 2. This formal thought disorder is prominent in early-onset schizophrenia 2
Grossly disorganized or catatonic behavior: Bizarre and disorganized behavior with marked attentional deficits 6
Negative symptoms: Including affective flattening (flat or inappropriate affect), paucity of thought or speech (alogia), avolition, social withdrawal, and anergia 1, 4, 7
Functional Deterioration
Marked deterioration in social, occupational, and self-care functioning below the level achieved before onset is required for diagnosis. 1 In children and adolescents, this manifests as failure to achieve age-appropriate levels of interpersonal, academic, or occupational development 1, 3.
Prodromal Phase Symptoms
Before overt psychotic symptoms emerge, patients typically experience a deterioration period characterized by: 1
- Marked social isolation and withdrawal 1
- Deterioration in occupational or academic functioning 1
- Peculiar behaviors such as food hoarding and poor hygiene 1
- Blunted or inappropriate affect 1
- Disordered thought processes (tangentiality, circumferentiality) 1
- Poverty of speech or speech content 1
- Odd beliefs or perceptions 1
- Anergia 1
Duration Criteria
The disturbances must be present for at least 6 months total, including an active phase of overt psychotic symptoms with or without prodromal or residual phases. 1 If the 6-month duration is not met, the diagnosis is schizophreniform disorder 1. ICD-10 allows diagnosis once sufficient symptoms have been present for 1 month or more 1.
Age-Specific Considerations
Adolescents and Young Adults
- Peak age of onset ranges from 15 to 30 years 1
- Onset before age 13 is quite rare (prevalence <1/10,000) 1, 5
- Early-onset schizophrenia (EOS) is defined as onset before age 18 years 1
- Very-early-onset schizophrenia (VEOS) develops before age 13 years 1
- Males predominate in early-onset cases with ratios of approximately 2:1 1
Symptom Presentation in Youth
- Positive symptoms (including hallucinations) increase linearly with age and are associated with IQs above 85 2
- Systematic delusions are less frequent in children and adolescents compared to adults 2
- Cognitive and language development affects the presentation and quality of delusional symptoms 2
- Disorganized speech with loose associations, illogical thinking, and impaired discourse abilities is characteristic 6, 2
Premorbid Abnormalities
The majority of patients with early-onset schizophrenia (up to 90%) have premorbid abnormalities, especially those with very-early-onset. 1 These include:
- Social withdrawal and isolation 1
- Disruptive behavior disorders 1
- Academic difficulties 1
- Speech and language problems 1
- Developmental delays 1
- Motor and social impairments 1
Critical Diagnostic Pitfalls
Differential Diagnosis Requirements
Bipolar disorder with psychotic features must be systematically ruled out, as approximately 50% of adolescents with bipolar disorder are initially misdiagnosed as having schizophrenia due to florid psychosis at onset. 1, 3 Longitudinal reassessment over time is the only accurate method for distinguishing these disorders 1, 3.
Additional exclusions required: 1
- Schizoaffective disorder 1
- Substance-induced psychosis (particularly cannabis) 1, 8
- General medical conditions 1
- Medication effects 1
Common Misinterpretation Risks
- Most children reporting hallucinations are not schizophrenic and many do not have psychotic disorders 3
- Formal thought disorder must be differentiated from developmental speech/language disorders 3, 2
- True psychotic symptoms must be distinguished from psychotic-like phenomena due to developmental delays, trauma exposure, or overactive imagination 3
- Cultural or religious beliefs may be misinterpreted as psychotic symptoms when taken out of context 3, 2
- In cases of childhood trauma, reports of psychosis-like symptoms may represent dissociative and/or anxiety phenomena, including intrusive thoughts/preoccupations, derealization, or depersonalization 2
- African-American youth are more likely to be mischaracterized as having psychotic conditions, requiring clinicians to actively guard against racial biases 3
Clinical Course and Phases
The American Academy of Child and Adolescent Psychiatry describes distinct phases: 3
Prodrome phase: Deteriorating function before overt psychotic symptoms, including social isolation, bizarre preoccupations, unusual behaviors, academic problems, and deteriorating self-care 3
Acute phase: Dominated by positive psychotic symptoms and functional deterioration 3
Recovery phase: Some ongoing psychotic symptoms, confusion, disorganization, and/or dysphoria 3
Residual phase: Follows the active phase with persistent negative symptoms even when positive symptoms improve 3
Chronic impairment: Approximately 50-60% of childhood and adolescent cases show adverse course and outcome 5