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ADHD

Attention deficit/hyperactivity disorder (ADHD) is characterized by impulsivity, inattention, and hyperactivity. Although often diagnosed in children, it’s nearly as common in adults.

Our evidence-based analysis on adhd features 23 unique references to scientific papers.

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Summary of ADHD

What is ADHD?

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.[2] 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]

What are the main signs and symptoms of ADHD?

People with ADHD can experience signs and symptoms of inattention, hyperactivity and impulsivity, or both.[3]

Hyperactivity & Impulsivity

  • Fidgeting, tapping, or squirming

  • Leaving one’s seat when expected to remain seated

  • Running around or climbing in inappropriate situations

  • An inability to play or take part in leisure activities quietly

  • Being “on the go” or acting as if “driven by a motor”

  • Talking excessively

  • Having trouble waiting one’s turn, interrupting others, or blurting out answers to questions before they’ve been completed.

Inattention

  • Difficulty paying attention to details

  • Making careless mistakes

  • Getting sidetracked from schoolwork, chores, or work responsibilities

  • Difficulty being organized

  • Avoiding, disliking, or being reluctant to do tasks that require long bouts of mental effort

  • Losing things that are necessary for tasks and activities (e.g., school materials, wallet, keys, glasses, cell phone)

  • Being easily distracted in daily activities

It’s worth noting that, because adults often internalize symptoms that are less socially acceptable, ADHD can present very differently in children versus adults. Some adult-specific symptoms include:[4][5][6]

  • Feeling restless

  • Having racing or scattered thoughts

  • Difficulty prioritizing tasks

  • Difficulty planning

  • Poor time management (e.g., missing or double-booking appointments)

  • Difficulty regulating emotions

How is ADHD diagnosed?

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.[8]

What are some of the main medical treatments for ADHD?

Except in children under age 5, medications are considered the first-line treatment for ADHD.[8][9] 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.[10][11] 

Other nonstimulant medications used for ADHD include atomoxetine,[12] bupropion,[13] and tricyclic antidepressants.[14]There is some preliminary research suggesting that modafinil may improve ADHD, but much more research is needed.[15]

Have any supplements been studied for ADHD?

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.[28741625]

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.[16][17]

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.[18]

Supplementing with phosphatidylserine (a phosphorus-containing lipid) seems to positively affect ADHD,[19] 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.

What's the connection between diet and ADHD?

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).[20] 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.

Are there any other treatments for ADHD?

Behavioral strategies can be used to manage ADHD symptoms, and include:[21]

  • 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.[22]

What causes ADHD?

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.[23][24] 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.[23] 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. Pooled twin studies suggest that the heritability of ADHD is nearly 80%.[25]

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The Human Effect Matrix looks at human studies to tell you what supplements affect ADHD.

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Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Supplement Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
grade-a Minor Very High See all 10 studies
Supplemental DHA above 300mg appears to be effective in reducing ADHD symptoms in children, and a few studies have shown that EPA alone may also have a benefit.
grade-b - Very High See 2 studies
There is currently very little evidence. It is possible that there is some effect on some symptoms, but much more research is needed.
grade-c Notable - See study
Modafinil appears to be able to reduce symptoms of ADHD in children when taken as a daily preventative at the lowest active dose

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Frequently Asked Questions and Articles on ADHD

Paying attention to omega-3s for ADHD
With more and more people being diagnosed with ADHD, there’s a continuing hunt for helpful treatments. Researchers tested an omega-3 supplement on young males, and also explored a potential dopamine-related mechanism.
Click here to see all 23 references.