ADHD Differential Diagnosis

1. Associated Conditions
   1. Language and Learning Disability (10-15%)
      1. Usually less hyperactive and more inattentive
   2. Tourette's Syndrome (70% with tics have ADHD)
   3. Oppositional Defiant Disorder (35-65% of ADHD patients)
   4. Conduct Disorder (10-20% of ADHD patients)
   5. Major Depression (20% of ADHD patients)
   6. Anxiety Disorder (25% of ADHD patients)
   7. Substance Abuse (20-40% of ADHD patients)
2. Differential Diagnosis: Psychiatric Conditions
   1. Low self esteem
   2. Major Depression
   3. Anxiety Disorder
   4. Conduct Disorder
   5. Oppositional Defiant Disorder
   6. Obsessive Compulsive Disorder
   7. Poor Social skills
   8. Substance Abuse
      1. Consider if symptom onset in adolescence
3. Differential Diagnosis: Medications
   1. Anticonvulsants
   2. Antihistamines
   3. Decongestants
   4. Beta agonists
4. Differential Diagnosis: General Medical Conditions
   1. Hypothyroidism
   2. Severe Anemia
   3. Lead Poisoning
   4. Chronic illness
   5. Hearing Impairment or vision Impairment
5. Differential Diagnosis: Neurologic Conditions
   1. Sleep disorders
   2. Tourette's Syndrome
   3. Seizure disorder (Petit mal)
   4. Other learning disabilities
   5. Language disorders
   6. Mental retardation
      1. Fragile X Syndrome
      2. Fetal Alcohol Syndrome
      3. Phenylketonuria
6. Differential Diagnosis: Environmental
   1. Unsafe or disruptive learning environment
   2. School curriculum not well matched to child's ability
   3. Family dysfunction or poor parenting
   4. Child Abuse or neglect
   5. Parental Psychopathology
7. References
   1. Biederman (1991) Am J Psychiatry 148:564-77
   2. Fletcher (1999) Pediatr Clin North Am 46:885-96
   3. Goldman (1998) JAMA 279:1100-7
   4. Hazel (1997) J Paediatr Child Health 33:131-7
   5. Smucker (2001) Am Fam Physician 64:817-32
   6. (2006) J Clin Psychiatry 8(4):224-33