Attention deficit hyperactivity disorder (“ADHD”) is a common childhood disorder characterized by developmentally inappropriate levels of hyperactivity, impulsivity, and inattention. ADHD is a complex disorder with substantial variation in cause, presentation, treatment, and outcomes. The exact causes of ADHD are poorly understood (Thapar et al. 2013). Potential risk factors include a combination of both genetic and environmental factors.
ADHD is a common affliction with worldwide prevalence estimated at approximately 7% (Thomas et al. 2015). ADHD symptoms typically start or are first noticed in preschool-age children (Daley et al. 2009). While symptoms may decline with age, ADHD symptoms, and impairments can persist into adolescence and adulthood (Geissler & Lesch 2011).
ADHD is often associated with substantial impairments in functioning and poor long-term outcomes. Pharmacological and non-pharmacological treatment options are available for symptom management and to improve function. Despite extensive advances in understanding this complex disorder, improved methods for diagnosis and treatment are desired.
The prevalence of ADHD is widely debated, with discussions of over- and under-diagnosis fueled by variations in estimates across time, geography, and evolving diagnostic criteria. A recent meta-analysis of 175 studies conducted over a 36-year period (Thomas et al 2015) found that the overall, pooled worldwide prevalence of ADHD in persons under 18 year old was 7.2%.
In the U.S., the American Psychiatric Association states in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) that 5% of children have ADHD. However, other studies have estimated higher rates in community samples.
According to data provided by the U.S. Centers for Disease Control and Prevention:
Approximately 11% of children 4-17 years of age have been diagnosed with ADHD as of 2011 (6.4 million children).
Rates of ADHD diagnosis increased an average of 3% per year from 1997 to 2006 and an average of approximately 5% per year from 2003 to 2011.
The percentage of children with an ADHD diagnosis continues to increase, from 7.8% in 2003 to 11.0% in 2011.
Boys are more than twice as likely as girls to receive an ADHD diagnosis (13.2% versus 5.6%).
The prevalence of ADHD diagnosis varies substantially by state, with the lowest rates reported in Nevada (5.6%) and highest rates reported in Kentucky (18.7%).
Functional Impairments and Comorbidities
ADHD may impact the quality of life of children and adolescents. ADHD is often associated with other conditions that may impair development and day-to-day living.
Lower Academic Performance
Poor academic performance is a common feature of children with ADHD. ADHD is associated with lower scores on standardized tests and lower grades (Barry et al. 2002; Loe & Feldman 2007). Children with ADHD are more likely to repeat a year of school or to drop out altogether (Barkley et al. 2006).
Mood and Anxiety Disorders
Mood and anxiety disorders are often observed in children with ADHD. In one study of 381 school age children with ADHD, half suffered from a mood disorder and one-third displayed symptoms of anxiety disorders.
ADHD is associated with other behavior disorders including conduct disorder (“CD”) and oppositional defiant disorder (“ODD”). Evidence suggests that children with both ADHD and behavioral disorders tend to be harder to treat (Villodas et al. 2012).
Substance Abuse / Misuse
Children with ADHD may be more likely to abuse substances later in life. Approximately one in four persons with substance dependence will also suffer from ADHD (van Emmerik-van Oortmerssen et al. 2012).
Approaches to ADHD Treatment
There is currently no cure for ADHD, however, various treatment options exist to manage symptoms and improve functioning. Pharmacological treatments include stimulant and non-stimulant medications. Non-pharmacological treatments include behavioral intervention and therapy.
Drug treatments have been proven effective for the short-term management of ADHD symptoms. Pharmacotherapy is often recommended as one part of a treatment strategy for children with moderate to severe levels of ADHD-related impairment (NICE 2008).
Methylphenidate, best known by its trade name Ritalin®, is the most prescribed medication for ADHD (Buitelaar & Medori 2010). Methylphenidate works by increasing levels of dopamine by blocking its reuptake.
Lisdexamphatamine dimesylate, sold under the trade name Vyvanse®, is a long-acting stimulant medication. Lisdexamphatamine dimesylate may be administered if methylphenidate is found to be lacking in efficacy.
Atomoxetine, sold under the trade name Strattera®, is a non-stimulant medication that works by increasing levels of the neurotransmitter noradrenaline. Some clinical trials suggest that atomoxetine is less effective than methylphenidate (Hanwella et al. 2011). Thus, atomoxetine may be administered to children who are unresponsive to methylphenidate. Atomoxetine may also be prescribed by clinicians who have concerns regarding the use of stimulant medications.
Non-Pharmacological Treatment Options
A number of non-pharmacological treatment options are available as intervention options for ADHD.
Intervention by a child’s parents or caregivers is recommended as first-line treatment for ADHD (NICE 2008). Recommended interventions include strategies aimed at increasing the frequency of adaptive behaviors while reducing disruptive behavior.
Similar to parenting interventions, classroom-based interventions commonly include behavior modification strategies for the teacher to improve problematic classroom conduct. Classroom-based interventions can also include strategies designed to improve academic performance.
Child Psychological Therapy
Psychological treatment may include sessions related to anger management, problem-solving, and social skills training. Although treatment with a psychologist is often recommended for children with ADHD (NICE 2008), evidence supporting its efficacy is currently limited (Toplak et al. 2008; Storebo et al. 2011).