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Primary disorder of vigilance , which is characterized by poor attention and concentration , as well as difficulties staying awake . These children tend to <unk> , yawn and stretch and appear to be hyperactive in order to remain alert and active .
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Mood disorders ( especially bipolar disorder and major depressive disorder ) . Boys diagnosed with the combined ADHD subtype are more likely to have a mood disorder . Adults with ADHD sometimes also have bipolar disorder , which requires careful assessment to accurately diagnose and treat both conditions .
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Anxiety disorders have been found to occur more commonly in the ADHD population .
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Obsessive @-@ compulsive disorder ( OCD ) can co @-@ occur with ADHD and shares many of its characteristics .
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Substance use disorders . Adolescents and adults with ADHD are at increased risk of substance abuse . This is most commonly seen with alcohol or cannabis . The reason for this may be an altered reward pathway in the brains of ADHD individuals . This makes the evaluation and treatment of ADHD more difficult , with serious substance misuse problems usually treated first due to their greater risks .
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Restless legs syndrome has been found to be more common in those with ADHD and is often due to iron deficiency anaemia . However , restless legs can simply be a part of ADHD and requires careful assessment to differentiate between the two disorders .
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Sleep disorders and ADHD commonly co @-@ exist . They can also occur as a side effect of medications used to treat ADHD . In children with ADHD , insomnia is the most common sleep disorder with behavioral therapy the preferred treatment . Problems with sleep initiation are common among individuals with ADHD but often they will be deep sleepers and have significant difficulty getting up in the morning . Melatonin is sometimes used in children who have sleep onset insomnia .
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There is an association with persistent bed wetting , language delay , and developmental coordination disorder ( DCD ) . Language delays can include auditory processing disorders such as short @-@ term auditory memory weakness , difficulty following instructions , slow speed of processing spoken language , and difficulties listening in distracting environments .
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= = Cause = =
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The cause of most cases of ADHD is unknown ; however , it is believed to involve interactions between genetic and environmental factors . Certain cases are related to previous infection of or trauma to the brain .
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= = = Genetics = = =
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Twin studies indicate that the disorder is often inherited from one 's parents with genetics determining about 75 % of cases . Siblings of children with ADHD are three to four times more likely to develop the disorder than siblings of children without the disorder . Genetic factors are also believed to be involved in determining whether ADHD persists into adulthood .
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Typically , a number of genes are involved , many of which directly affect dopamine neurotransmission . Those involved with dopamine include DAT , DRD4 , <unk> , TAAR1 , <unk> , COMT , and DBH . Other genes associated with ADHD include SERT , <unk> , <unk> , <unk> , <unk> , <unk> , and BDNF . A common variant of a gene called <unk> is estimated to be responsible for about 9 % of cases and when this variant is present , people are particularly responsive to stimulant medication . The 7 repeat variant of dopamine receptor D4 ( DRD4 – 7R ) causes increased inhibitory effects induced by dopamine and is associated with ADHD . The DRD4 receptor is a G protein @-@ coupled receptor that inhibits <unk> cyclase . The DRD4 – 7R mutation results in a wide range of behavioral phenotypes , including ADHD symptoms reflecting split attention .
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Evolution may have played a role in the high rates of ADHD , particularly hyperactive and impulsive traits in males . Some have hypothesized that some women may be more attracted to males who are risk takers , increasing the frequency of genes that predispose to hyperactivity and impulsivity in the gene pool . Others have claimed that these traits may be an adaptation that helped males face stressful or dangerous environment with , for example , increased impulsivity and exploratory behavior . In certain situations , ADHD traits may have been beneficial to society as a whole even while being harmful to the individual . The high rates and heterogeneity of ADHD may have increased reproductive fitness and benefited society by adding diversity to the gene pool despite being detrimental to the individual . In certain environments , some ADHD traits may have offered personal advantages to individuals , such as quicker response to predators or superior hunting skills .
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People with Down syndrome are more likely to have ADHD .
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= = = Environment = = =
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In addition to genetics , some environmental factors might play a role . Alcohol intake during pregnancy can cause fetal alcohol spectrum disorders which can include ADHD or symptoms like it . Children exposed to certain toxic substances , such as lead or polychlorinated biphenyls , may develop problems which resemble ADHD . Exposure to the organophosphate insecticides chlorpyrifos and <unk> phosphate is associated with an increased risk ; however , the evidence is not conclusive . Exposure to tobacco smoke during pregnancy can cause problems with central nervous system development and can increase the risk of ADHD .
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Extreme premature birth , very low birth weight , and extreme neglect , abuse , or social deprivation also increase the risk as do certain infections during pregnancy , at birth , and in early childhood . These infections include , among others , various viruses ( measles , varicella zoster encephalitis , rubella , enterovirus 71 ) . At least 30 % of children with a traumatic brain injury later develop ADHD and about 5 % of cases are due to brain damage .
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Some studies suggest that in a minority of children , artificial food dyes or preservative may be associated with an increased prevalence of ADHD or ADHD @-@ like symptoms but the evidence is weak and may only apply to children with food sensitivities . The United Kingdom and the European Union have put in place regulatory measures based on these concerns . In a minority of children , intolerances or allergies to certain foods may worsen ADHD symptoms .
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Research does not support popular beliefs that ADHD is caused by eating too much refined sugar , watching too much television , parenting , poverty or family chaos ; however , they might worsen ADHD symptoms in certain people .
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= = = Society = = =
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The diagnosis of ADHD can represent family dysfunction or a poor educational system rather than an individual problem . Some cases may be explained by increasing academic expectations , with a diagnosis being a method for parents in some countries to get extra financial and educational support for their child . The youngest children in a class have been found to be more likely to be diagnosed as having ADHD possibly due to their being developmentally behind their older classmates . Behaviors typical of ADHD occurs more commonly in children who have experienced violence and emotional abuse .
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According to social construction theory it is societies that determine the boundary between normal and abnormal behavior . Members of society , including physicians , parents , and teachers , determine which diagnostic criteria are used and , thus , the number of people affected . This leads to the current situation where the DSM @-@ IV arrives at levels of ADHD three to four times higher than those obtained with the ICD @-@ 10 . Thomas Szasz , a supporter of this theory , has argued that ADHD was " invented and not discovered . "
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= = Pathophysiology = =
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Current models of ADHD suggest that it is associated with functional impairments in some of the brain 's neurotransmitter systems , particularly those involving dopamine and norepinephrine . The dopamine and norepinephrine pathways that originate in the ventral tegmental area and locus coeruleus project to diverse regions of the brain and govern a variety of cognitive processes . The dopamine pathways and norepinephrine pathways which project to the prefrontal cortex and striatum are directly responsible for modulating executive function ( cognitive control of behavior ) , motivation , reward perception , and motor function ; these pathways are known to play a central role in the pathophysiology of ADHD . Larger models of ADHD with additional pathways have been proposed .
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= = = Brain structure = = =
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In children with ADHD , there is a general reduction of volume in certain brain structures , with a proportionally greater decrease in the volume in the left @-@ sided prefrontal cortex . The posterior parietal cortex also shows thinning in ADHD individuals compared to controls . Other brain structures in the prefrontal @-@ striatal @-@ cerebellar and prefrontal @-@ striatal @-@ thalamic circuits have also been found to differ between people with and without ADHD .
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= = = <unk> pathways = = =
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Previously it was thought that the elevated number of dopamine transporters in people with ADHD was part of the pathophysiology but it appears that the elevated numbers are due to adaptation to exposure to stimulants . Current models involve the mesocorticolimbic dopamine pathway and the locus coeruleus @-@ noradrenergic system . ADHD psychostimulants possess treatment efficacy because they increase neurotransmitter activity in these systems . There may additionally be abnormalities in <unk> and cholinergic pathways . <unk> of glutamate , a <unk> with dopamine in the mesolimbic pathway , seems to be also involved .
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= = = Executive function and motivation = = =
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The symptoms of ADHD arise from a deficiency in certain executive functions ( e.g. , attentional control , inhibitory control , and working memory ) . Executive functions are a set of cognitive processes that are required to successfully select and monitor behaviors that facilitate the attainment of one 's chosen goals . The executive function impairments that occur in ADHD individuals result in problems with staying organized , time keeping , excessive procrastination , maintaining concentration , paying attention , ignoring distractions , regulating emotions , and remembering details . People with ADHD appear to have unimpaired long @-@ term memory , and deficits in long @-@ term recall appear to be attributed to impairments in working memory . The criteria for an executive function deficit are met in 30 – 50 % of children and adolescents with ADHD . One study found that 80 % of individuals with ADHD were impaired in at least one executive function task , compared to 50 % for individuals without ADHD . Due to the rates of brain maturation and the increasing demands for executive control as a person gets older , ADHD impairments may not fully manifest themselves until adolescence or even early adulthood .
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ADHD has also been associated with motivational deficits in children . Children with ADHD find it difficult to focus on long @-@ term over short @-@ term rewards , and exhibit impulsive behavior for short @-@ term rewards . In these individuals , a large amount of positive reinforcement effectively improves task performance . ADHD stimulants may improve persistence in ADHD children as well .
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= = = Intelligence = = =
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Overall , studies have shown that people with ADHD tend to have lower scores on intelligence quotient ( IQ ) tests . The significance of this is controversial due to the differences between people with ADHD and the difficulty determining the influence of symptoms , such as distractibility , on lower scores rather than intellectual capacity . In studies of ADHD , higher IQ ’ s may be over represented because many studies exclude individuals who have lower IQ ’ s despite those with ADHD scoring on average 9 points lower on standardized intelligence measures . As a result , we may have less of an accurate understanding of ADHD .
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= = Diagnosis = =
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ADHD is diagnosed by an assessment of a person 's childhood behavioral and mental development , including ruling out the effects of drugs , medications and other medical or psychiatric problems as explanations for the symptoms . It often takes into account feedback from parents and teachers with most diagnoses begun after a teacher raises concerns . It may be viewed as the extreme end of one or more continuous human traits found in all people . Whether someone responds to medications does not confirm or rule out the diagnosis . As imaging studies of the brain do not give consistent results between individuals , they are only used for research purposes and not diagnosis .
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In North America , DSM @-@ 5 criteria are used for diagnosis , while European countries usually use the ICD @-@ 10 . With the DSM @-@ IV criteria a diagnosis of ADHD is 3 – 4 times more likely than with the ICD @-@ 10 criteria . It is classified as neurodevelopmental psychiatric disorder . Additionally , it is classified as a disruptive behavior disorder along with oppositional defiant disorder , conduct disorder , and antisocial personality disorder . A diagnosis does not imply a neurological disorder .
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Associated conditions that should be screened for include anxiety , depression , oppositional defiant disorder , conduct disorder , and learning and language disorders . Other conditions that should be considered are other neurodevelopmental disorders , tics , and sleep apnea .
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Diagnosis of ADHD using quantitative electroencephalography ( QEEG ) is an ongoing area of investigation , although the value of QEEG in ADHD is currently unclear . In the United States , the Food and Drug Administration has approved the use of QEEG to evaluate the morbidity of ADHD .
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= = = Diagnostic and Statistical Manual = = =
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As with many other psychiatric disorders , formal diagnosis is made by a qualified professional based on a set number of criteria . In the United States , these criteria are defined by the American Psychiatric Association in the DSM . Based on the DSM criteria , there are three sub @-@ types of ADHD :
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ADHD predominantly inattentive type ( ADHD @-@ PI ) presents with symptoms including being easily distracted , forgetful , daydreaming , disorganization , poor concentration , and difficulty completing tasks .
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ADHD , predominantly hyperactive @-@ impulsive type presents with excessive <unk> and restlessness , hyperactivity , difficulty waiting and remaining seated , immature behavior ; destructive behaviors may also be present .
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ADHD , combined type is a combination of the first two subtypes .
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This subdivision is based on presence of at least six out of nine long @-@ term ( lasting at least six months ) symptoms of inattention , hyperactivity – impulsivity , or both . To be considered , the symptoms must have appeared by the age of six to twelve and occur in more than one environment ( e.g. at home and at school or work ) . The symptoms must be not appropriate for a child of that age and there must be evidence that it is causing social , school or work related problems .
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= = = International Classification of Diseases = = =
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In the ICD @-@ 10 , the symptoms of " hyperkinetic disorder " are analogous to ADHD in the DSM @-@ 5 . When a conduct disorder ( as defined by ICD @-@ 10 ) is present , the condition is referred to as hyperkinetic conduct disorder . Otherwise , the disorder is classified as disturbance of activity and attention , other hyperkinetic disorders or hyperkinetic disorders , unspecified . The latter is sometimes referred to as hyperkinetic syndrome .
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= = = Adults = = =
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Adults with ADHD are diagnosed under the same criteria , including that their signs must have been present by the age of six to twelve . Questioning parents or guardians as to how the person behaved and developed as a child may form part of the assessment ; a family history of ADHD also adds weight to a diagnosis . While the core symptoms of ADHD are similar in children and adults they often present differently in adults than in children , for example excessive physical activity seen in children may present as feelings of restlessness and constant mental activity in adults .
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= = = Differential diagnosis = = =
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Symptoms of ADHD such as low mood and poor self @-@ image , mood swings , and irritability can be confused with dysthymia , <unk> or bipolar disorder as well as with borderline personality disorder . Some symptoms that are due to anxiety disorders , antisocial personality disorder , developmental disabilities or mental retardation or the effects of substance abuse such as intoxication and withdrawal can overlap with some ADHD . These disorders can also sometimes occur along with ADHD . Medical conditions which can cause ADHD type symptoms include : hyperthyroidism , seizure disorder , lead toxicity , hearing deficits , hepatic disease , sleep apnea , drug interactions , untreated celiac disease , and head injury .
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Primary sleep disorders may affect attention and behavior and the symptoms of ADHD may affect sleep . It is thus recommended that children with ADHD be regularly assessed for sleep problems . <unk> in children may result in symptoms ranging from the classic ones of yawning and rubbing the eyes , to hyperactivity and inattentiveness . <unk> sleep apnea can also cause ADHD type symptoms .
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= = Management = =
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The management of ADHD typically involves counseling or medications either alone or in combination . While treatment may improve long @-@ term outcomes , it does not get rid of negative outcomes entirely . Medications used include stimulants , atomoxetine , alpha @-@ 2 adrenergic receptor agonists , and sometimes antidepressants .
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= = = Behavioral therapies = = =
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There is good evidence for the use of behavioral therapies in ADHD and they are the recommended first line treatment in those who have mild symptoms or are preschool @-@ aged . Psychological therapies used include : psychoeducational input , behavior therapy , cognitive behavioral therapy ( CBT ) , interpersonal psychotherapy , family therapy , school @-@ based interventions , social skills training , behavioral peer intervention , organization training , parent management training , and neurofeedback . Behavior modification and neurofeedback have the best support .
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Parent training and education have been found to have short @-@ term benefits . There is little high quality research on the effectiveness of family therapy for ADHD , but the evidence that exists shows that it is similar to community care and better than a placebo . Several ADHD specific support groups exist as informational sources and may help families cope with ADHD .
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Training in social skills , behavioral modification and medication may have some limited beneficial effects . The most important factor in reducing later psychological problems , such as major depression , criminality , school failure , and substance use disorders is formation of friendships with people who are not involved in delinquent activities .
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Regular physical exercise , particularly aerobic exercise , is an effective add @-@ on treatment for ADHD in children and adults , particularly when combined with stimulant medication , although the best intensity and type of aerobic exercise for improving symptoms are not currently known . In particular , the long @-@ term effects of regular aerobic exercise in ADHD individuals include better behavior and motor abilities , improved executive functions ( including attention , inhibitory control , planning , and cognitive processing speed , among other cognitive domains ) , and better memory without causing any side effects . Exercising while on stimulant medication augments the effect of stimulant medication on executive function . It is believed that these short @-@ term effects of exercise are mediated by an increased abundance of synaptic dopamine and norepinephrine in the brain .
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= = = Medication = = =
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Stimulant medications are the pharmaceutical treatment of choice . They have at least some effect in the short term in about 80 % of people . Methylphenidate appears to improve symptoms as reported by teachers and parents .
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There are a number of non @-@ stimulant medications , such as atomoxetine , bupropion , guanfacine , and clonidine that may be used as alternatives , or added to stimulant therapy . There are no good studies comparing the various medications ; however , they appear more or less equal with respect to side effects . Stimulants appear to improve academic performance while atomoxetine does not . There is little evidence on their effects on social behaviors . Medications are not recommended for preschool children , as the long @-@ term effects in this age group are not known . The long @-@ term effects of stimulants generally are unclear with one study finding benefit , another finding no benefit and a third finding evidence of harm . Magnetic resonance imaging studies suggest that long @-@ term treatment with amphetamine or methylphenidate decreases abnormalities in brain structure and function found in subjects with ADHD . <unk> , due to its lack of addiction liability , may be preferred in those who are at risk of recreational or compulsive stimulant use . Guidelines on when to use medications vary by country , with the United Kingdom 's National Institute for Health and Care Excellence recommending use only in severe cases , Switzerland strongly limits the authorised medications , while most United States guidelines recommend medications in most age groups .
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<unk> of stimulants may occur and result in a lack of response or later loss of effectiveness . This is particularly common in adolescents and adults as approved dosing is based on school @-@ aged children , causing some practitioners to use weight based or benefit based off @-@ label dosing instead .
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While stimulants and atomoxetine are usually safe , there are side @-@ effects and contraindications to their use . A large overdose on ADHD stimulants is commonly associated with symptoms such as stimulant psychosis and mania ; although very rare , at therapeutic doses these events appear to occur in approximately 0 @.@ 1 % of individuals within the first several weeks after starting amphetamine or methylphenidate therapy . Administration of an antipsychotic medication has been found to effectively resolve the symptoms of acute amphetamine psychosis . Regular monitoring has been recommended in those on long @-@ term treatment . Stimulant therapy should be stopped periodically to assess for continuing need for medication , decrease possible growth delay , and reduce tolerance . Long @-@ term misuse of stimulant medications at doses above the therapeutic range for ADHD treatment is associated with addiction and dependence . Untreated ADHD , however , is also associated with elevated risk of substance use disorders and conduct disorders . The use of stimulants appears to either reduce this risk or have no effect on it . The safety of these medications in pregnancy is unclear .
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= = = Diet = = =
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