Characteristics
of ADHD
(4-2-15)
Defining features: a persistent pattern of inattention, hyperactivity, impulsivity more frequent and severe than age and gender peers in similar circumstances
Prevalence: As in all things, influenced by criteria selection, operationalization, and method of assessment
DSM 5 reports prevalence of approximately 5% in children and 2.5% in adults
CDC analysis of 2003 National Survey of Children's Health (NSCH) data indicated that in 2003 approximately 4.4 children aged 4 to 17 years were reported to have a history of ADHD diagnosis; 2.5 million (56%) were reported to be currently taking medication for this disorder
national prevalence male: 11.0%
national prevalence female: 4.4%
national prevalence total: 7.8% (95% confidence interval 7.4 to 8.1)
Onset: at least some symptoms appear before age 12 (DSM 5; previously 7 in DSM-IV)
Course: there is usually some attenuation of symptoms with increasing age, especially the overactivity; but some degree of symptoms and associated social and academic impairment continue in a majority of diagnosed cases.Children diagnosed with ADHD are at risk for involvement in substance use and antisocial activities as adolescents and young adults. ADHD appears to interact with conduct problems to increase risk of greater and more diverse substance use (Barkley, Fischer, Smallish, & Fletcher, 2004).
Subtypes:(DSM 5): ADHD, Combined Presentation
ADHD, Predominantly Inattentive Presentation
ADHD, Predominantly Hyperactive/Impulsive Presentation
Gender: More frequent in males than females.
Sex ration more skewed in clinic than in population sample.
Comorbidity: Approximately 50% of clinic populations of children diagnosed with ADHD also meet criteria for ODD.
DSM 5 notes a 50% comorbidity for ODD with ADHD combined presentation and 25% comorbidity for predominantly inattentive presentation
DSM 5 notes 25% comorbidity for Conduct Disorder with ADHD combined presentation
DSM 5 notes that: "Most children and adolescents with disruptive mood dysregulation disorder have symptoms that also meet criteria for ADHD; a lesser percentage of children with ADHD have symptoms that meet criteria for disruptive mood dysregulation disorder." (p. 65)
Other frequently comorbid disorders include: Mood Disorders, Anxiety Disorders, Learning Disorders, tic disorders, autism spectrum disorders, and Communication Disorders.
DSM 5 notes that "Specific learning disorder commonly co-occurs with ADHD." (p. 65)
DSM 5 notes that major depressive disorder: "occurs in a minority of individuals with ADHD but more often than in the general population" (p. 65)
Even in the absence of formal reading disabilities, children with ADHD may unexpected weaknesses in learning and recall new information (Cutting et al., 2003)
At least 50% of children diagnosed with Tourette's Disorder also meet criteria for a diagnosis of ADHD, but most children with ADHD do not meet criteria for Tourette's. In children who show both problems, the onset of the ADHD typically precedes the onset of Tourette's.Tourette's syndrome is a tic disorder that consists of both vocal and motor tics
Tourette's syndrome is ofter associated in the public's mind with coprolalia (obscene speech, "potty mouth") but while this occurs, it is not terribly common in individuals with Tourette's; vocal (grunts, throat clearing, clicks, etc.) tics are more common than verbal tics (meaningful remarks, words); embarrasing remarks are more common than coprolalia. When there are verbal aspects to Tourette's syndrome, this does appear to represent a failure of inhibitory control within the CNS (we all know the words we are no suppose to use in public).
In the past a diagnosis of a Pervasive Developmental Disorder precluded a concurrent diagnosis of ADHD (because comoribity was so high), in DSM 5 concurrent diagnoses of Autism Spectrum Disorder and ADHD are allowed
The relationship between ADHD in youth and an adolescent/adult diagnosis of Bipolar Mood Disorder remains a topic of active investigation and some controversy. Most children with diagnosed ADHD do not go on to develop manic episodes and bipolar disorder, but a small subpopulation does. These cases may represent:a) the early symptoms of bipolar disorder misdiagnosed as ADHD
b) the comorbid occurrence of two mental disorder, possibly due to shared risk factors or etiological influences
c) a unique variation of ADHD/Bipolar Disorder
a fluctuating course of ADHD symptoms and adjustment,
poor response to treatment with CNS stimulants, and
a strong family history of Bipolar Disorder are often seen
as risk factors for later comorbidity with manic-depressive illnessHazell et al. (2003) found that manic symptoms in young males with ADHD predicted lower global functioning but not a diagnosis of Bipolar Disorder in early adulthood, casting some doubt on the link between manic symptoms in childhood and later bipolar disorder.
additionally--some, perhaps many, youth diagnosed with bipolar disorder do not appear to go on to manifest classical bipolar disorder (full manic or hypomanic episodes) as adult, raising further questions about the link the conditions
DSM 5 has attempted to address these issues by creation of a new diagnostic category: Disruptive Mood Dysregulation Disorder
Gender and ADHD
Biederman et al. (2002) studied 140 boys & 140 girls with ADHD and 120 boys and 122 girls without ADHD
ADHD in girls was characterized by the prototypical symptoms of the disorder (Inatt., Impul., & Hyperact.), comorbid psychopathology, social dysfunction, cognitive impairments, school failure, and adversity in family environment.
Overall the profile of psychiatric comorbidity for ADHD was similar in boys and girls
The only significant gender-by-diagnosis interaction was for substance use disorders: ADHD was a stronger risk factor for substance use disorders in girls than in boys
this finding would support targeting substance abuse prevention programs to girls with ADHD
The other -by-diagnosis interactions were not significant: the other gender differences between boys and girls with ADHD were the same as the gender differences observed for boys and girls without ADHD
ADHD in girls was more likely to be predominantly the inattentive type
less likely to be associated with a learning disability in reading or mathematics
less likely to be associated with problems in school or fewer spare-time activities
These differences in phenotypic presentation may help account for the difference in referral rates to clinics of boys and girls with ADHD
A significant discrepancy has been noted between the male to female ratio for clinic-referred (10 to 1) and community samples (3 to 1) of children with ADHD
Biederman, J., Mick, E., Faraone, S.V., Braaten, E., Doyle, A., Spencer, T., Wilens, T.E., Frazier, E., & Johnson, M.A. (2002)
Cutting, L.E., Koth, C.W., Mahone, E.M., & Denckla, M.B. (2003). Evidence for unexplained weaknesses in learning in children with Attention-Deficit/Hyperactivity Disorder without reading disabilities. Journal of Learning Disabilities, 36, 259-269.