Post-traumatic stress disorder (PTSD) can develop at any age, but research consistently shows that working-age adults, particularly those aged 18–64, experience the highest prevalence and lifetime risk of PTSD. According to the National Comorbidity Survey Replication (NCS-R) and subsequent large-scale studies (including the World Mental Health Surveys), the lifetime prevalence of PTSD in the general population is approximately 6–9% in the United States and slightly lower globally (around 4–6%).

The 30–44 age group often shows the highest current (12-month) prevalence, followed closely by the 45–59 group. Several factors explain this pattern:

1. Higher exposure to trauma during adulthood: Adults in these age ranges are more likely to experience or witness interpersonal violence, sexual assault, combat (especially veterans aged 18–40), serious accidents, or sudden loss of loved ones—traumas strongly linked to PTSD.
2. Military service: A significant proportion of PTSD cases occur in veterans and active-duty personnel, who are predominantly under 45.
3. Sexual violence: Women aged 16–24 have the highest risk of sexual assault, one of the traumas most likely to cause PTSD (risk up to 30–50% after rape).

Children and adolescents can develop PTSD (lifetime prevalence ~4–8%), but diagnostic rates are lower due to different symptom presentation and under-reporting. Older adults (65+) generally have the lowest current prevalence, partly because of survivor effects, different coping mechanisms, and lower exposure to new trauma, though many carry chronic PTSD from earlier life events.

In summary, while PTSD affects all ages, adults aged 25–54 especially women and military veterans are the most commonly affected demographic in most epidemiological studies conducted in high-income countries over the past two decades.