…the mental health professions, and perhaps the culture at large, has been lowering the bar for what counts as a mental illness. The list of disorders in the Diagnostic and Statistical Manual (DSM) of the American Psychiatric Association tripled between 1952 and 1994, when it included almost three hundred disorders, including Avoidant Personality Disorder (which applies to many people who formerly were called shy), Caffeine Intoxication, and Female Sexual Dysfunction. The number of symptoms needed to justify a diagnosis has fallen, and the number of stressors that may be credited with triggering one has increased.

— Steven Pinker, Enlightenment Now