Early-Onset Schizophrenia Age Definition
Early-onset schizophrenia (EOS) is defined as onset before 18 years of age, with very-early-onset schizophrenia (VEOS) representing a subcategory defined as onset before 13 years of age. 1
Terminology and Age Cutoffs
The American Academy of Child and Adolescent Psychiatry establishes the following age-based classifications:
- Early-Onset Schizophrenia (EOS): Onset before age 18 years 1
- Very-Early-Onset Schizophrenia (VEOS): Onset before age 13 years 1
This terminology is consistently supported across multiple sources, with research confirming that EOS encompasses childhood and adolescent onset (under 16-17 years), while VEOS specifically refers to onset at or before age 12 years 2, 3.
Epidemiological Context
Understanding the rarity of these conditions helps contextualize the age definitions:
- VEOS (onset before 13) is extremely rare, representing only 1% of all schizophrenia cases, with a prevalence of approximately 1 in 10,000 births 4
- Only 4% of all schizophrenic disorders occur before age 10 4
- The incidence increases dramatically during adolescence, with 12-34% of cases occurring before age 18 4
- In one Danish study spanning 13 years, only 4 patients were younger than 13 years at onset, and only 28 were younger than 15 years 5
Clinical Significance of Age Cutoffs
The distinction between VEOS and EOS carries important prognostic implications:
- Onset before age 12 is uniformly associated with worse disability at outcome 6
- Onset before age 15 correlates with higher ratings of negative symptoms in adulthood 6
- Onset before age 21 results in greater social impairment compared to later onset 6
The youngest reported cases in the literature had onset at 3 years and 5.7 years of age, though diagnosis at such young ages requires extremely careful scrutiny 5.
Diagnostic Criteria Consistency
Importantly, the diagnostic criteria for schizophrenia remain identical across all age groups—the same DSM-IV criteria apply to children, adolescents, and adults regardless of age of onset 1, 4. The age-based terminology (EOS vs. VEOS) serves to identify populations with distinct clinical characteristics and prognoses rather than representing different diagnostic entities.