Attention Deficit Hyperactivity Disorder (ADHD)

Attention deficit/hyperactivity disorder (ADHD) is a behavioral condition characterized by inattention, impulsivity, and hyperactivity. Most people experience these behaviors from time to time, but in ADHD, they are more severe, happen more often, and interfere with a person’s ability to function socially, at school, or in the workplace.^[1] ADHD is divided into three subtypes by predominant symptomatology: Inattentive (ADHD-I), Hyperactive-Impulsive (ADHD-HI), and Combined (ADHD-C). Symptom clusters can change as individuals mature and develop.^[2]

People with ADHD can show signs of inattention, hyperactivity, impulsivity, or both.^[3] This can manifest as difficulty paying attention to details, getting sidetracked from schoolwork, troubles with organization, and being easily distracted. Other behaviors include fidgeting or squirming, inability to remain seated when expected, inappropriate running or climbing, and talking excessively. ADHD in adults is often internalized and may present as restlessness, scattered thoughts, and poor time management.^[4]

In children, at least six of the symptoms mentioned need to be present to qualify for a diagnosis; in adults, only five. In both cases, these symptoms need to be present for more than 6 months and interfere with academic, occupational, or social functioning.^[5]

Except in children under age 5, medications are considered the first-line treatment for ADHD.^[6][7] Short- and long-acting forms of amphetamines and methylphenidate — stimulants that increase levels of dopamine and norepinephrine in the brain — are most commonly prescribed and considered highly effective for treating ADHD.^[8][9]

Other nonstimulant medications used for ADHD include atomoxetine,^[10] bupropion,^[11] and tricyclic antidepressants.^[12]There is some preliminary research suggesting that modafinil may improve ADHD, but much more research is needed.^[13]

Fish oil contains the omega-3 fatty acids DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), which have well-supported anti-inflammatory properties and can regulate neurotransmitter and immune function, and as a result, may improve ADHD.^[14]

Ginkgo biloba increases blood flow in the human brain and the signaling of serotonin and norepinephrine in rats, which may contribute to its mild, positive effect on ADHD.^[15][16]

Both L-carnitine and acetyl-L-carnitine are present in brain cells and play an important role in energy production — it’s possible that by increasing mitochondrial activity in neurons and promoting dopamine signaling, carnitine could improve symptoms of ADHD.^[17]

Supplementing with phosphatidylserine (a phosphorus-containing lipid) seems to positively affect ADHD,^[18] which is likely due to its important role in adjusting receptor, enzyme, and ion channel activity, and consequently, affecting the signaling of most neurotransmitters in the brain.

A number of dietary interventions for ADHD have been studied, including the elimination of artificial food colorings, diets high in polyunsaturated fatty acids (PUFAs), and the few-foods diet (a type of elimination diet that gradually reintroduces foods based on how a person’s symptoms change).^[19] High-PUFA diets aren’t likely to improve ADHD symptoms, but the few-foods diet is promising. More research on dietary artificial food coloring intake is necessary before it can be recommended for treating ADHD.

Behavioral strategies can be used to manage ADHD symptoms, and include:^[20]

• Keeping a consistent schedule
• Minimizing external distractions
• Setting small, reachable goals
• Identifying unintentional reinforcement of negative behaviors
• Using charts and checklists
• Limiting choices
• Using calm discipline in children (e.g., time out)

Psychotherapy and cognitive behavioral therapy can be helpful for children and adults with ADHD, although it’s not recommended as a substitute for medication.^[21]

The exact etiology of ADHD is unknown but is thought to involve structural and neurochemical alterations in brain regions responsible for executive function, memory, and information processing.^[22][23] Norepinephrine and dopamine signaling play a major role in the function of these brain regions, and individuals with ADHD tend to have lower levels of both of these neurotransmitters than individuals without ADHD.^[22]

ADHD has a strong genetic component. The risk of ADHD is increased by 2–8 times in individuals who have a parent or sibling with ADHD, and pooled twin studies suggest that the heritability of ADHD is nearly 80%.^[24]