The Diagnostic & Statistical Manual of Mental Disorders (DSM) is one of the most widely used means of defining mental disorders. The use of a diagnostic criteria for each mental illness/condition allows agreement between clinians and specialists concerning the topography of each condition. The manual is maintained by the American Psychiatric Association.

According to the DSM (4th Edition):

Attention Deficit/Hyperactivity Disorder

Either (1) or (2):

(1) six (or more) of the following symptoms of inattention have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental levels:

Inattention

• (A) Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
• (B) Often has difficulty sustaining attention in tasks or play activities.
• (C) Often does not seem to listen when spoken to directly
• (D) Often does not follow through on instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behaviour or failure to understand instructions).
• (E) Often has difficulty organising tasks and activities
• (F) Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolwork or homework).
• (G) Often loses things necessary for tasks or activities (e.g., toys, school assignments, pencils, books, or tools).
• (H) Is often easily distracted by extraneous stimuli.
• (I) Is often forgetful in daily activities.

2. six or more of the following symptoms of hyperactivity-impulsivity have persisted for at least 6 months to a degree that is maladaptive and inconsistent with developmental level:

Hyperactivity

• (A) often fidgets with hands or feet or squirms in seat.
• (B) often leaves seat in classroom or in other situation in which remaining seated is expected.
• (C) often runs about or climbs excessively in situations in which it is inappropriate ( in adolescents or adults, may be limited to subjective feelings of restlessness)
• (D) often has difficulty playing or engaging in leisure activities quietly
• (E) is often "on the go" or often acts as if "driven by a motor"
• (F) often talks excessively.

Impulsivity

• (G) often blurts out answers before questions have been compleated.
• (H) often has difficulty awaiting turn.
• (I) often interrupts or intrudes on others (e.g., at school or work and at home).

B. Some hyperactive-impulsive or inattentive symptoms that caused impairment were present before age 7 years.

C. Some impairment from the symptoms is present in two or more settings (e.g., at school or work and at home).

D. There must be clear evidence of clinically significant impairment in social, academic, or occupational functioning.

E. The symptoms do not occur exclusively during the course of a Pervasive Developmental Disorder, Schizophrenia, or other Psychotic Disorder and are not better accounted for by another mental disorder (e.g., Mood Disorder, Anxiety Disorder, Dissociative Disorder, or a Personality Disorder).

314.01 Attention-deficit/hyperactivity disorder, combined type: if both criteria A1 and A2 are met for the past six months.

314.00 Attention-deficit/hyperactivity disorder, predominantly inattentive type: if criterion A1 is met but criterion A2 is not met for the past six months.

314.01 Attention-deficit/hyperactivity disorder, predominantly hyperactive–impulsive type: if criterion A2 is met but criterion A1 is not met for the past six months.

From: Diagnostic & Statistical Manual of Mental Disorders (DSM) (4th Edition), (1994), American Psychiatric Association, 1400 K Street, N.W., Washington D.C. 20005.