Age younger than 35 years has been used as a factor in identifying young
adult chronic mentally ill patients, a group considered difficult to treat
due to their rebelliousness, lack of insight about their mental illness,
and increased likelihood of showing symptoms of borderline or antisocial
personality disorder. In a sample of psychiatric outpatients, the authors
found that a subgroup of patients under age 35 fit this profile, while
other patients under age 35 and nearly all patients over age 35 did not.
The authors conclude that age is a legitimate factor in identifying a
subgroup of challenging patients and that such patients may outgrow many
troublesome characteristics as they age.