Until recently, it has been assumed that the symptoms of Attention Deficit Disorder disappear by the time adulthood is reached. However, more recent studies suggest that the symptoms persist into adulthood for up to 70% of individuals diagnosed with the disorder. Overall, it has been estimated that anywhere from two to five million adults suffer with ADD. Many adults were never diagnosed as children; thus, are not aware of the source of the problems they may be experiencing in relation to social, academic, and interpersonal functioning.

Diagnosing an adult with ADD requires a thorough case history, including childhood, academic and behavioral history. Psychoeducational and vocational testing can be useful as well, providing insight into suitable interventions for the adult with ADD. Often, the adult with ADD has had a history of struggling with issues like low self esteem, substance abuse, depression, and relationship problems. The first step in taking charge of the disorder is education. Many adults have little understanding of their disability, rather intuitively know that they are distractible, short tempered, and impulsive.

The criteria which must be fulfilled in order to be diagnosed as having an Attention Deficit Disorder are set out by the American Psychiatric Association. They have defined four subtypes of the disorder with accompanying symptoms:

ADHD – Inattentive Type

The individual must exhibit at least six of the following:

Failure to give close attention to details/careless mistakes
Difficulty sustaining attention
Appearance of not listening
Difficulty following directions
Difficulty with organization
Avoidance of tasks requiring sustained mental effort
Tendency to often lose things
Tendency to be easily distracted
Forgetfulness in daily activities

ADHD-Hyperactive/Impulsive Type

The individual must experience at least six of the following:

Fidgeting with hands or feet
Difficulty remaining seated
Feelings of restlessness
Actions which appear "driven"
Difficulty waiting turn
Interruption of others

Excessive talking
Tendency to blurt out answers or questions.

ADHD-Combined Type

The individual meets both sets of attention and hyperactive/impusive criteria.

ADHD-Not Otherwise Specified

The individual demonstrates some but not enough of the characteristics to reach a full diagnosis.