False
The statement is false—schizophrenia onset in females is not exclusive to ages 25-35 years, though this range does fall within one of the peak onset periods for women.
Age of Onset in Females: The Evidence
The peak age of onset for schizophrenia in females occurs between 20-30 years, which overlaps with but is not limited to the 25-35 year range stated in the question 1. More broadly, the American Academy of Child and Adolescent Psychiatry reports that the overall peak ages of onset for schizophrenia range from 15 to 30 years across both genders 2.
Key Gender Differences in Onset Timing
Males develop schizophrenia approximately 5 years earlier than females, with male peak onset occurring between ages 15-25 years 1, 3.
Females demonstrate a bimodal distribution of onset ages, with a first peak between ages 20-30 years and a second, flatter peak occurring at menopausal age (44-49 years) 4.
Approximately 10% of women show no evidence of psychosis until after age 40 years, and onset after age 35 occurs in 17% of women compared to only 2% of men 3.
Why the Age Range is Not Exclusive
The evidence clearly demonstrates that female onset is not confined to any single age bracket:
Early-onset cases occur in females: While males predominate in very early onset schizophrenia (before age 13) at a 2:1 ratio, females can and do develop the disorder during adolescence 2, 1.
Late-onset cases are more common in females: The second peak at menopausal age (44-49 years) is unique to women and represents a substantial proportion of female cases 4.
The protective effect of estrogen explains why premenopausal women have lower incidence rates, with this hormonal protection diminishing at menopause, accounting for the second peak 4.
Clinical Implications
The male-to-female ratio equalizes as age increases 2, 1. In early-onset schizophrenia (before age 18), males outnumber females approximately 2:1, but this ratio evens out in later-onset cases 2.
For paranoid schizophrenia specifically, women have significantly later onset than men, particularly when onset occurs after age 30 years 5. However, in early-onset cases (before age 30), there may be no gender difference in age at onset 5.
Common Pitfall to Avoid
Do not assume schizophrenia cannot occur outside typical age ranges in either gender. While the 20-30 year range represents peak incidence in females, clinicians must remain vigilant for onset in adolescence, mid-life, and even late life 3, 4. The youngest reported cases had onset at ages 3 and 5.7 years, though diagnosis at such young ages requires extremely careful scrutiny 2, 6.