Missed or delayed diagnosis often occurs if a disease that is typically diagnosed in juveniles (such as asthma) is present in adults, and vice versa (such as arthritis).
Even some mental health disorders, whose ages of onset have been found to be harder to define than physical illnesses may have a mutated component.
Pathological changes pertaining to disorders often become more detailed and less fickle before they can be defined in the American Psychiatric Association's DSM.
[11] The typical onset of many mental disorders in late adolescence may reflect the critical development that happens at this time.
[20] Reed and Bryant demonstrated this by limiting the lifespan of the flies to a few days, which made late-life mutations invisible to selection since they occurred after reproduction.