Attention Deficit Hyperactivity Disorder (ADHD)

What is ADHD?

Attention deficit hyperactivity disorder (ADHD) is a common neurobehavioural disorder which mostly affects children, but can also affect adults.

This disorder is characterised by the symptoms of impulsiveness, very short attention span and hyperactivity. While these symptoms may occur in normal, healthy children and adults, they are displayed to an extreme level in those with ADHD to the extent that they disrupt their life in many ways.

There are three main types of ADHD according to which symptoms present the strongest in an individual:

• Mainly inattentive type – inability to pay attention to detail, listen to instructions or complete tasks
• Mainly hyperactive-impulsive type – unable to sit still, very restless and fidgety, wont wait and jumps in and interrupts others
• Combination of inattention and hyperactivity – this type is characterised by having symptoms of both the two types

Some facts about ADHD

• Boys are more likely to be diagnosed with ADHD than girls
• It is estimated that around 3-8% of children worldwide may have ADHD
• ADHD was previously named ADD (attention deficit disorder) but was renamed in 1994 by the American Psychiatric Association (APA)
• ADHD is part of a group of conditions, called Autistic Spectrum Disorder and children with this disorder are normally very intelligent but often do not do well at school due to their inability to focus their attention
• Children with ADHD are often either over stimulated or under stimulated or both, which can cause them to have problems with coordination and balance and make them extremely sensitive to their surroundings and external stimulus
• Children with ADHD learn things non-sequentially and often try to do several things at the same time, which means that they can become very frustrated if they cannot accomplish everything at once
• Children with ADHD would have been difficult babies that did not easily settle, who would have had problems sleeping, waking often and needing a lot of attention

Symptoms of ADHD

Symptoms for ADHD are divided into two areas, with some people having predominantly one type of symptom over the other and some have a combination of all symptoms. Symptoms of impulsiveness and hyperactivity often precede those of inattention.

Symptoms need to be present for over 6 months before this condition can be diagnosed, as many other conditions can can also have some of the same symptoms.

Inattention symptoms

• Disorganised
• Difficulty with tasks that require organising and planning
• Are easily distracted by any type of external stimuli
• Forgetting homework, papers, pens or other items at various places
• Has difficulty listening to and following instructions
• Losing or forgetting toys, pencils, paper or other items
• Not completing activities (or projects) and leaving them unfinished to go to the next one
• Making simple mistakes in any activity that requires concentration
• Unable to give close attention to details in any activity engaged in (school work or other activity)

Hyperactivity (or impulsiveness) symptoms

• Blurts out answers to questions before the question has even been finished
• Can’t sit still and enjoy quiet activities, such as reading
• Constantly interrupts others
• Runs and climbs in situations that may be inappropriate or even dangerous
• Finds it difficult to stand in line or wait their turn
• “On the go” or constantly in motion
• Restless, fidgeting and squirming if in one place for too long
• Running and climbing
• Unable to sit quietly at the table with others
• Cannot stand waiting in line, waiting for their turn

In addition to this, children with ADHD have other symptoms associated with this condition:

Hypersensitive senses

With exaggerated senses, children with ADHD are very sensitive and all their senses are far more heightened than other children:

• Hearing – this can be a major source of distraction, as they can become distracted by any noise from the task at hand
• Smell – strong smells can overwhelm a child with ADHD and cause distress
• Taste – artificial additives can cause a great deal of abnormal behaviour
• Touch – sensitivity to touch can show up as being really ticklish, unable to wear certain fibres and having an aversion to being hugged
• Vision – bright lights can make it difficult for children with ADHD to concentrate on reading and any other activities that require any level of concentration
• Emotions – children with ADHD are usually very sensitive to the emotions of others (especially the negative ones) and will often reflect those emotions in their own behaviour

Spatial awareness issues

Children with ADHD often have problems with coordination and balance and this is thought to be due to a faulty vestibular system.

High intelligence

Children with ADHD are often highly intelligent who need this intelligence to be brought out, by the use of appropriate teaching methods. Children with ADHD are very visual and tactile and these traits need to be utilised in order to inspire them and get their attention, because if they feel that they do not understand the activity they tend to get very frustrated and switch off, giving the inaccurate impression they are slow learners.

Causes of ADHD

Even with over 30 years of research into this condition, scientists still do not know exactly what causes ADHD. Many theories have been proposed (and most lie in the realms of neurobiology or genetics), but there are new theories every day.

Some of the possible causes of ADHD that have been proposed are listed here (and some children’s ADHD could be a combination of a number of these causes, not every child will have the same causes in any case):

Environmental chemicals

Studies show that certain environmental chemicals may play a role in causing ADHD to some extent

• Alcohol – studies show that women who drink alcohol while pregnant have a greater risk for having a child who will develop ADHD
• Cigarette smoke – studies show that women who smoke while pregnant have a greater risk for having a child who will develops ADHD
• Lead – studies show that children who are exposed to lead (either through lead paint in their house or from pollution from busy roads) are more likely to develop ADHD

Food additives

A recent study completed in 2007 has suggested that food additives cause ADHD symptoms such as impulsive, hyperactivity, inattentiveness, impulsiveness and the authors of this study advised parents they should remove all food additives from children’s diet in order to stop symptoms – the problem additives are artificial food colours and preservatives.

Genetics

ADHD seems to run in families with about 25% of people in families of people with ADHD also have this condition (while the general populace has a rate of 5%).

Sugar

Some studies have shown either no effect (or a negligible one) of sugar causing ADHD; other studies have shown that a diet high in refined sugar does cause behavioural problems in children especially, while other studies show that some children with ADHD have problems with the way they process sugar.

Nutritional deficiencies

Some research suggests that nutritional deficiencies may play a part in causing some ADHD symptoms, especially of the minerals magnesium and zinc and especially omega-3 essential fatty acids.

Social factors and child rearing techniques

There is currently no proof that ADHD is caused solely by social factors or how a child is raised, but it is well-known that if these these (and if they are very negative), they can play a very detrimental role in exacerbating existing ADHD.

Prevention of ADHD

There is very little that can be done to prevent any of the known risk factors that are either genetic or in some other way unpreventable, which are known to be associated with the development of ADHD.

There is though much that can be done to prevent some of the risk factors that are controllable and so prevent much of the extreme behavioural problems associated with ADHD or even prevent it from occurring in the first place in some circumstances.

Research shows that there are some risk factors associated with the development of ADHD in a child.

Non-preventable risk factors

• Genetics – families who have children that have ADHD have a higher risk of those children producing their own children who also have ADHD
• Neurotransmitter problems – scientists theorise that some children with ADHD have a problem with the way they metabolise the neurotransmitter dopamine and possibly also the neurotransmitter norepinephrine too. On the other hand, children with ADHD that do not have the hyperactivity may have excessive histamine production in their brain that could be the root cause of their symptoms
• Excessive testosterone production – studies show that there is a link between excessive levels of testosterone and the diagnosis of ADHD. This has lead scientists to suggest that this could be a possible reason why ADHD is much more common in boys than girls
• Essential fatty acid metabolism – some children (and adults) with ADHD may have a problem with the way their body metabolises essential fatty acids (EFA), such as the omega-3 EFA docosahexaenoic acid (DHA). This can then result in a deficiency in this nutrient which can display in the symptoms associated with ADHD
• Vaccinations – there is some evidence (although there is conflicting evidence against it) that vaccines with a mercury preservative are linked to a higher incidence in Autistic Spectrum Disorders (and ADHD is just one of them)

Preventable risk factors

Ways to possibly reduce the risk of a child developing ADHD in the first place (or at least reducing some of the symptoms associated with ADHD).

• Pregnant mothers should not smoke – studies show that when pregnant, mothers should not smoke any type of cigarettes. The toxic chemicals in the cigarettes can pass through the placenta to the unborn foetus and cause adverse effects to the baby, leading to possible behavioural problems and ADHD
• Pregnant mothers should not drink alcohol – studies show that women who drink while they are pregnant (and quite possibly also when they are breastfeeding) are increasing their chances of having a child who has ADHD. In fact, there is a condition called foetal alcohol syndrome which can develop in the unborn child of a mother that drinks during her pregnancy, that causes a whole range of behavioural problems that are very similar to ADHD (inattention, lack of control, learning difficulties) and may actually be misdiagnosed as ADHD
• Breastfeeding mothers should not smoke – studies show that even when breastfeeding, mothers should not smoke any type of cigarettes, as the toxic chemicals in the cigarettes can enter the breast milk and cause adverse effects to the baby, leading to possible behavioural problems and ADHD
• Breastfeeding mothers should not drink – studies show that even when breastfeeding, mothers should not drink any alcohol as the alcohol can enter the breast milk and cause adverse effects to the baby, leading to possible behavioural problems and ADHD
• Exposure to lead – these days, with more focus on the environment, most cars run on unleaded petrol and most paints do not contain lead like they used to, but some children are still exposed to high levels of lead if they live in an older house (which hasn’t been renovated and still has the lead paint), have old cots (that may have been painted with lead paint) or live or go to school on a busy road in a large city. These children will be exposed to lead almost on a daily basis and could then display symptoms of ADHD. Exposure to other heavy metals (mercury, cadmium especially) have the same effect as lead and should also be avoided
• Ensure adequate omega 3 fatty acids in the diet – some children who have ADHD may have an essential fatty acid deficiency . Children with ADHD often display symptoms that are very similar to omega-3 essential fatty acid (EFA) deficiency – behavioural problems, lack of concentration, learning difficulties, sleep problems, mood problems and would benefit from having more of this vital nutrient in their diet. Studies show that Western society as a whole seems to be lacking in omega-3 EFA in their diet and so children with a predisposition to ADHD suffer even more if their diet is lacking this nutrient
• Avoid artificial additives – studies have shown that artificial additives (colours, flavours, preservatives) are known to cause many behavioural problems in young children and should be eliminated from the diet to reduce incidence of these problems

Complications of ADHD

While ADHD is not a terminal condition (it does not cause mortality in those who are sufferers), it can cause a number of irritating behaviours which may not be able to be well tolerated by others. Behaviours such as:

• Being really loud and noisy
• Having aggressive tendencies
• Being totally out of control
• Displaying major irritability and mood changes
• Being very overbearing and obnoxious

These behaviours can be very alienating – other people wont understand the reason for this behaviour and may not be able to handle someone who behaves this way, especially if they continue to be like this without respite.

If ADHD is not diagnosed and treated in early childhood, the child could grow up displaying a great deal of anti-social behaviour, including expulsion from school, involvement in drug and alcohol abuse, motor vehicle accidents and crime. Ultimately unresolved ADHD can lead to a great deal of frustration and unhappiness for the child (or adult) and should be remedied as soon as possible.

When to see a doctor about ADHD

A family doctor should be consulted if a child starts to display any type of behavioural problems consistently and over a period of time, especially when they are not associated with with any upsetting events in the child’s life. A family doctor is in the best position to give advice on the types of tests that will be required to help determine a solution to any possible problems.

If though, the child only displays some behavioural problems infrequently, just on certain occasions, then it would be advisable to check their diet (are they getting enough foods high in omega-3 EFA, are they lacking in foods high in zinc or magnesium, are they eating too many foods with artificial additives) first and see if this provides a resolution to the problem.

The information on the alternative- complementary treatment of ADHD should be looked at to determine if any of the simple suggestions there provide a resolution for any behavioural problems. If they do, you could just mention this to your family doctor next time you see him/her to let them know the situation.

A doctor (or other health professional) will usually suggest the simple options first anyway, in order to eliminate any simple reasons for the behavioural problems before ordering the tests for ADHD.

Diagnosis of ADHD

ADHD is diagnosed through a series of tests, questionnaires and assessment for other psychological disorders by a paediatrician, psychiatrist, registered psychologist or other health professional.

At least six of the symptoms of ADHD (from both the inattention and hyperactivity symptoms) need to be present for at least 6 months prior to a child turning seven, in at least two of their social situations (school, home, etc) for a child to be diagnosed with ADHD.

It is important that parents not self-diagnose their children with ADHD, as all healthy young children have a limited attention span and it may just be nothing. To determine if a child has ADHD, always seek the advice of a health professional.

It is also essential that children with any type of behavioural problems who are suspected of having ADHD have other tests, such as:

• Allergy testing – children with ADHD are very sensitive to all influences and this includes allergens, which can cause hyperactive behaviour through the adverse effects they cause in sensitive individuals
• Blood tests – to determine if they have any nutritional deficiencies (such as omega-3 EFA, magnesium or zinc especially) which could be exacerbating their symptoms and to test blood sugar levels for hypoglycaemia
• Food sensitivity – children with ADHD often have food allergies or sensitivities and much of their subsequent behaviour may be due to this sensitivity; an elimination diet needs to be followed to work out if this food is causing any of the behavioural problems. The most common food sensitivity that can cause behavioural problems are: cow’s milk, wheat (or gluten), oranges (and other citrus fruit), chocolate, peanuts, soy, eggs, corn, oats, apples, tomatoes. In order to test a food sensitivity, that food (and foods containing it) must be totally eliminated from the diet for two weeks (as must all foods with any artificial additives) and after that, the food can be re-introduced back into the diet to see if there are any reactions to it. This requires a lot of vigilance and strict monitoring and could be better accomplished with the help of a registered dietician or naturopath
• Heavy metal testing – hair analysis or blood tests should be done to determine if there has been chronic exposure to any heavy metals, such as lead, cadmium or mercury (chelation therapy is usually used to get rid of any heavy metal toxicity in the body, but it needs to be done by a qualified professional)

Conventional treatment of ADHD

Conventional treatment that is recommended today uses a combination of a number of different types of therapy (including medication usually) for the treatment of this condition. The combination of therapies used will depend on each case of ADHD:

Behavioural therapy

There are various types of behavioural therapies and counselling that are used to treat ADHD (usually in conjunction with medication)

• Emotional counselling
• Family counselling
• Organisation training
• Parent skills training
• Psychotherapy
• Scheduling – how to
• Social skills training
• Time management training

Medication

This consists of prescribing either non-stimulating or stimulating drugs depending on the symptoms of the child (or adult) suffering from ADHD:

• Stimulating drugs – these drugs are commonly used in ADHD and regulate the activity of the neurotransmitters, especially dopamine, but also norepinephrine (noradrenaline); the drugs have a specific time-span of action and can be either short-term (4-5 hours), or medium-term (6-8 hours) or long-term (10-12 hours). The most well-known drug in these class of medications is Ritalin, which has many known side effects. The side effects can be usually (but not totally) mitigated though lowering the dosage or switching to a different type of drug in the same class (different to Ritalin, but same drug type)
• Non-stimulating drugs – these drugs act as selective norepinephrine re-uptake inhibitors (SNRIs), which modify the way that the neurotransmitter norepinephrine is regulated in the brain of a person suffering from ADHD and this helps to control their symptoms by reducing the level of their mental stimulation

There is quite a lot of controversy regarding the prescription of the conventional drug Ritalin (and other medications) used to treat ADHD, with advocates against Ritalin claiming that Ritalin (and similar drugs) are over prescribed and ADHD over diagnosed.

Approximately 1 in 200 children in Australia are being treated with drugs for ADHD, the most common being Ritalin (this figure is higher in the USA). Ritalin works by stimulating the central nervous system to function differently and helps concentration, but it has a great deal of side effects which may counteract the positive effects. Long term side effects of Ritalin are not yet known.

The side effects of Ritalin include – height retardation, involuntary movements, tic, hallucinations or delusions, seizures, headaches, hair loss, zombie-like behaviour.

The drugs used to treat ADHD work on norepinephrine’s activity in the brain. Norepinephrine is a neurotransmitter, which regulates mood and level of activity. It is an excitatory neurotransmitter, which means that it excites the brain cells into activity.

Scientists believe that norepinephrine plays a big role in the development or the exacerbation of ADHD, as norepinephrine is important in regulating attention, activity and impulsiveness. Although scientists believe norepinephrine plays a role in ADHD, they are not entirely sure how it plays a role in this condition.

Alternative / complementary treatment of ADHD

There is some controversy about the prescription of the conventional drug Ritalin (or other psychotropic medications) for ADHD, with alternative practitioners advocating natural therapies over conventional drugs. There are many studies which show certain supplements and foods help to reduce symptoms of ADHD and these therapies should be tried first before resorting to medication as a last resort.

The following are the treatments advocated by alternative therapists.

Vitamins, minerals and other supplements

• Magnesium – studies show that children and adults with ADHD (especially if they have the following symptoms: fidgeting, anxiety, restlessness, poor motor coordination, learning difficulties) may be displaying symptoms of mild magnesium deficiency which are usually alleviated through magnesium supplementation; This is because magnesium is an excellent muscle relaxant and may greatly reduce the symptoms of some children and adults with certain symptoms of ADHD described above
• Essential fatty acids – numerous studies show that the essential fatty acids (especially omega-3 essential fatty acids) play an important role in regulating brain activity in children (and adults) with ADHD; studies have shown that children with ADHD greatly benefit from omega 3 EFA as many children and adults with ADHD could be either deficient in these essential fatty acids or may not be metabolising them properly and this could lead to a deficiency as well
• Zinc – this important mineral regulates essential fatty acids and the neurotransmitters activity in the body; some studies have shown that children with ADHD have a deficiency in zinc
• Iron – many children (and adults), especially females are deficient in iron, which may cause symptoms associated with ADHD; care should be made with supplementation as it is toxic in high doses to children and a blood test should be taken to determine blood iron and haemoglobin (as well as other levels of other nutrients) to determine if iron supplementation is necessary and required
• Vitamin B6 – this important vitamin is required as a precursor to many of the brains;’ important neurotransmitters such as dopamine, norepinephrine and serotonin; one study showed that this vitamin was helpful for alleviating symptoms associated with nervousness and restlessness; other studies have confirmed these findings
• B Vitamins – not only should vitamin B6 be supplemented but also the rest of the other B vitamins too (B1-thiamin, B2-riboflavin, B3- niacin, B5-pantothenic acid, B12-cyanocobalamin) as well as the B vitamin co-factors (folic acid especially). The B vitamins assist with proper nerve activity and may assist with reducing some hyperactivity symptoms as well as detoxifying the body from any artificial additives that may have been eaten
• Vitamin C – may be especially required in children who have had chronic heavy metal (especially lead) exposure which can lead to an over stimulation of histamine in the brain. Vitamin C acts as a natural anti-histamine and can reduce some symptoms in some children with ADHD

Dietary modifications

• Remove all processed foods – this includes all soft drinks, all canned and processed meats (from the deli), processed cheeses, instant soup, ice cream, toppings, puddings, cakes, pizza, take-away food
• Limit sugar intake – try to reduce sugar in the diet, which includes raw sugar added to tea and cereal and also the hidden sugar in most processed foods
• Remove all foods with artificial additives – studies now show that many artificial additives (colours, flavours and preservatives) could be responsible for many of the behavioural symptoms of children with ADHD and so should be totally banned from their diet. This includes all lollies (sweets), cakes, toppings, some cereals, snack bars
• Eat 5-6 smaller meals – a diet that consists of natural, unprocessed foods (without any artificial additives) and smaller meals may help the digestive system deal with any possible food allergies through the smaller meals which do not put as much stress on the digestive system as larger meals

Lifestyle modifications

• Get adequate sleep – adequate and regular amounts of sleep, including a regular bedtime are vital to help a child (and adult) calm down and settle at bed time; it gives them a sense of stability and routine
• Get adequate exercise – getting adequate exercise is vital to help a child with ADHD who has abundant reserves of energy, burn up some of that energy so that they can sleep properly, calm down and relax. Some type of physical activity that the child can excel at is advisable on a daily basis
• Limit TV and computer time – too much time watching television or playing on the computer is not advised even for children without ADHD; for children with ADHD, both the television and the computer provide far too much sensory stimulation which is not advised, as they can only exacerbate symptoms
• Use occupational therapy – occupational therapists design programs that are aimed to cater to children with beahvioural and learning difficulties, such as those with ADHD. A referral to a good occupational therapist can be obtained either through your family doctor or through a local health centre. The types of activities that occupational therapists use are: spinning nets, wool or twine onto something in one direction and then unravelling it again (care needs to be taken with some children who may get dizzy from this activity); touching different types of textures and asking the child to try to remember and identify the texture again, just ensure movements are long and slow; trampolining is a perfect activity for a child with ADHD, as it allows them to expend their energy in a safe manner and it also helps stimulate their vestibular system, aim for about 10 minute a day; puzzles, mazes, tracing, colouring in, cutting out shapes; card games, playing Simon says, memory games
• Reduce stress in the home – this one may be a little difficult to achieve, especially if stress in the home is unavoidable; parents should thought, keep in mind that children with ADHD especially, pick up on the sensory (unspoken) information around them and if the stress and tension continues without abate, it can cause the child to play up even more

Alternative treatments

• Naturopath – children with ADHD will benefit from a visit to a naturopath who can analyse their symptoms, recommend an elimination diet, provide nutritional supplements and monitor progress. Parents who take their child to a naturopath must advise their doctor to ensure it does not conflict with any medications the child is taking

Always ensure that you notify your medical practitioner of any supplements that you want to take – it may interfere with other medication or conditions you have. Confirm with your doctor it is safe to take before you try it.

Living with ADHD

Management of children (and adults) with attention deficit hyperactivity disorder (ADHD) should be more focused on determining what the triggers are and how much of an effect they have and reducing them.

General triggers that can cause behavioural problems are:

• Allergies – to foods, plants, pets and any other allergen can trigger behavioural problems, especially when the allergy is not known to exist
• Environmental toxins – from lead in paint, to lead in the petrol of older cars, mercury from amalgam fillings and some fish, as well as excess copper, can all trigger behavioural problems
• Food additives – especially artificial colours, flavours and preservatives should be completely avoided
• Shopping centres – there is just too much sensory stimulation in shopping centres, especially at busy times of the day or year and so should be avoided
• Sugar – especially excessive amounts can cause an over-stimulation and create hyperactive behaviour

The triggers above should all be eliminated and then re-introduced one by one, a little at a time to determine if and what type of effect they have on behaviour, concentration and memory.

Adults with ADHD, especially if it is newly diagnosed, should implement the same strategies recommended for children.

Caring for someone with ADHD

Partner

Adults with ADHD need to have supportive partners who can handle someone who has a lot of energy and who is very creative. They need to have a lot of patience and compassion:

• Don’t clutter your home – studies show that people with ADHD may be too stimulated when they are surrounded by a lot of clutter around them, so always try to clean up any mess
• Don’t surprise your partner – adults with ADHD often do not respond well to surprises, the more bigger the surprise, the worse the possible reaction
• Encouragement and support – it is really important to encourage and support your partner to help them cope with their condition. Try to also encourage them to visit support groups for other people who have ADHD

Friends

People who have friends with ADHD can help to support their friends by the following strategies:

• Don’t surprise your friend – adults with ADHD often do not respond well to surprises, the more bigger the surprise, the worse the possible reaction (so no big surprise birthday parties for your friend)
• Encouragement and support – it is really important to encourage and support your friend to help them cope with their condition

Parents

Parents of children with ADHD need to implement some strategies to help deal with them:

• Behavioural programs – there are many behaviour modification programs that parents can take their children, which can be very helpful in providing useful ways on how best to deal with a child which has ADHD. Try your doctor, local health centre or hospital for information about these programs
• Build self-esteem – try to engage the child with ADHD in activities that they are good at, as this can help build their self confidence. Always offer lots of praise and encouragement when a child does well at anything
• Consistency – keep rules consistent, but do not overwhelm your child with thousands of rules as they will not listen, you will get frustrated and the vicious circle of behavioural problems with start again
• Keep information short – children with ADHD often have trouble with their attention span, so if you need to give them any information, it should be kept short, concise and to the point, to avoid any confusion when their attention invariably wanders
• No surprises – children with ADHD generally do not cope well with surprises of any kind, which could cause them to have behavioural problems
• Reduce visual (and other ) stimulation – too much time on the computer, watching television, listening to loud music and even fluorescent lights all can over stimulate a child with ADHD and should be limited (in the case of fluorescent lights, they can be removed altogether and normal lighting used)
• Remove all clutter – this also helps children to stay calm by reducing the amount of stimulus around them, which can distract them
• Routine – ensure that meals, shower/bathing, bedtime are always at the same time every night as this gives the child with ADHD a sense of stability; set regular times for activities and help children stick to them to help them learn about organisation and planning

Children with ADHD are generally very visual and creative, but often have problems following instructions in order. They may also have problems at school, due to the amount of concentration required in activities.

Parents are the best to helping their child who has ADHD get better. They just need to learn about the resources they have available to help them help their child.

References

• Douglas L Leslie, Robert A Kobre, Brian J Richmand, Selin Aktan Guloksuz, James F Leckman. Temporal Association of Certain Neuropsychiatric Disorders Following Vaccination of Children and Adolescents: A Pilot Case-Control Study. PMID: 28154539. PMCID: PMC5244035 DOI:10.3389/fpsyt.2017.00003
• Tao Ke, Alexey A Tinkov, Antoly V Skalny, Aaron B Bowman, Joao B T Rocha, Abel Santamaria, and Michael Aschner. Developmental exposure to methylmercury and ADHD, a literature review of epigenetic studies. Environ Epigenet. 2021; 7(1): dvab014. Published online 2021 Nov 22. doi: 10.1093/eep/dvab014. Accessed 14 May 2024

Last reviewed and updated: 14 May 2024