American Psychiatric Association's Diagnostic and Statistics Manual (DSM-IV) criteria for Attention Deficit (ADHD)

A.  Either (1) or (2):

    (1) Inattention: at least *6* of the following symptoms of 
        inattention have persisted for at least 6 months to a 
        degree that is maladaptive and inconsistent with 
        developmental level: 
        
        (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 to what is being said to 
            him/her; 
        
        (d) often does not follow thru on instructions and fails 
            to finish schoolwork, chores, or duties in the 
            workplace (not due to oppositional behavior or failure 
            to understand instructions); 
        
        (e) often has difficulties organizing tasks and activities; 
        
        (f) often avoids or strongly dislikes tasks (such as 
            schoolwork or homework) that require sustained mental 
            effort; 
        
        (g) often loses things necessary for tasks or activities 
            (e.g., school assignments, pencils, books, tools, or 
            toys); 
        
        (h) is often easily distracted by extraneous stimuli; 
        
        (i) often forgetful in daily activities.
    
    (2) Hyperactivity-Impulsivity: at least *4* 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) leaves seat in classroom or in other situations in 
            which remaining seated is expected; 
        
        (c) often runs about or climbs excessively in situations 
            where 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.
    
       Impulsivity:
       
       (e) often blurts out answers to questions before the 
           questions have been completed; 
       
       (f) often has difficulty waiting in lines or awaiting turn 
           in games or group situations.
    
B. Onset no later than age 7.

C. Symptoms must be present in 2 or more situations (e.g., at 
   school, work, and at home).

D. The disturbance causes clinicaly significant distress or 
   impairment in social, academic, or occupational functioning.

E. Does not occur exclusively during the course of PDD, 
   Schizophrenia or other Psychotic Disorder, and is not better 
   accounted for by Mood, Anxiety, Dissociative, or Personality 
   Disorder.

Code based on type:

314.00 ADHD, Predominantly Inattentive Type if criterion A(1) is 
met but not criterion A(2) for the past 6 months.

314.01 ADHD, Predominantly Hyperactive-Impulsive Type: if 
criterion A(2) is met but not criterion A(1) for the past 6 
months.

314.01 ADHD, Combined Type: if both criteria A(1) and (2) are met 
for past 6 months [note: should this be 314.02?  It's not clear - 
RDF]

314.9 is ADHD NOS, for other disorders with prominent symptoms of 
attention-deficit or hyperactivity-impulsivity that do not meet 
criteria above.