User:A peydai/sandbox

Signs and symptoms
ADHD is a neurodevelopmental disorder that is mainly characterized by symptoms of inattention (e.g., lack of focus and disorganization), hyperactivity (restlessness in adults), and impulsivity (e.g., inability to wait to talk or to react). The symptoms primarily present themselves in childhood and often continue into adulthood. The symptoms can be difficult to define, as it is hard to draw a line at where normal levels of inattention, hyperactivity, and impulsivity end and significant levels requiring interventions begin.[54] Frequent problems in individuals with ADHD are cademic difficulties and problems with relationships.[52]

Subtypes
Girls with ADHD tend to display fewer hyperactivity and impulsivity symptoms but more symptoms pertaining to inattention and distractibility.[56] Symptoms of hyperactivity tend to go away with age and turn into "inner restlessness" in teens and adults with ADHD.[27]

People with ADHD of all ages are more likely to have problems with social skills, such as social interaction and forming and maintaining friendships. This is true for all subtypes. About half of children and adolescents with ADHD experience social rejection by their peers compared to 10–15% of non-ADHD children and adolescents. People with attention deficits are prone to having difficulty processing verbal and nonverbal language which can negatively affect social interaction. They also may drift off during conversations, miss social cues, and have trouble learning social skills.[57]

Difficulties managing anger are more common in children with ADHD[58] as are poor handwriting[59] and delays in speech, language and motor development.[60][61] Although it causes significant difficulty, many children with ADHD have an attention span equal to or better than that of other children for tasks and subjects they find interesting.[17]

ADHD also affects academic achievement of individuals across the lifespan (i.e., from school age children and adolescents, to adults at the college level). For example, children with ADHD tend to have lower grades, poor verbal and mathematics standardized test scores, and greater chances of repeating a school year. Also, studies involving young adults with ADHD show that these individuals have a history of poor academic outcome with many dropping out of high school and college before graduation.

Executive function and motivation
The symptoms of ADHD arise from deficiency in certain executive functions (e.g., attentional control, inhibitory control, and working memory).[71][131][132][142] Executive functions are a set of cognitive processes that are required successfully select and monitor behaviors that facilitate the attainment of one's chosen goals.[71][132][142] Impairments in the executive function of individuals with ADHD leads to difficulties with organization, efficient time management, maintaining concentration, paying attention, ignoring distractions, regulating emotion, and remembering details. The impairments also cause excessive procrastination.[71][131][132] 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.[71][143] The criteria for an executive function deficit are met in 30–50% of children and adolescents with ADHD.[144] 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.[145] 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.[71]

ADHD has also been associated with motivational deficits in children.[146] Children with ADHD often find it difficult to focus on long-term over short-term rewards, and exhibit impulsive behavior for short-term rewards.[146] This impulsive behavior can hinder long-term goal pursuits such as academic achievement.

Studies that have looked at delay discounting (i.e., reduction in the present value of a reward when there is a delay to its receipt) in adults and children with ADHD have revealed that, these individuals tend to show a preference for smaller monetary rewards that are immediately available over larger monetary rewards that are available over time (e.g., prefer to have 31$ today instead of 85$ in seven days). This desire for smaller immediate rewards however, is not independent of IQ. That is, ADHD children with higher IQ tend to wait for a larger reward that is available in the future.

Diagnosis
Diagnosis of ADHD using quantitative electroencephalography (QEEG) is an ongoing area of investigation, although the value of QEEG in ADHD is currently unclear.[151][152] In the United States, the Food and Drug Administration has approved the use of QEEG to evaluate ADHD.[153] The approved test uses the ratio of EEG theta to beta activity to guide diagnosis; however, at least five studies have failed to replicate the finding.[154][155]

ADHD can also be diagnosed using computerized tests of attention, such as Continuous Performance Task (CPT). CPT is a computer based measure of attention and impulsivity and has been used in research with ADHD children for the past 40 years. Although a computerized test is not sufficient for a diagnosis of ADHD, the presence of at least one such test is necessary for diagnosis of specific cognitive deficits that may accompany ADHD.

Self-rating scales, such as the ADHD rating scale and the Vanderbilt ADHD diagnostic rating scale are used in the screening and evaluation of ADHD.[156] Another popular self-rating scale that is typically used for ADHD screening in adults is the Conner’s Adult ADHD Rating Scale (CAARS). The CAARS is used to measure the presence, and severity of ADHD symptoms in adults aged 18 and older.

Adults
It is estimated that between 2–5% of adults have ADHD.[27] Around 25–50% of children with ADHD continue to experience ADHD symptoms into adulthood, while the rest experiences fewer or no symptoms.[2][27] Currently, most adults remain untreated.[160] Many adults with ADHD without diagnosis and treatment have a disorganized life and some use non-prescribed drugs or alcohol as a coping mechanism.[31] Other problems may include relationship and job difficulties, and an increased risk of criminal activities.[27] Associated mental health problems include: depression, anxiety disorder, and learning disabilities.[31]

Many adults show subclinical symptoms of ADHD. That is, they do show traits such as inattention, hyperactivity, and impulsivity but do not meet the full criteria for a clinical diagnosis. Individuals with subclinical ADHD exhibit impaired functioning in various domains, much like the impact full ADHD symptoms exert. Examples include impaired social functioning and high association with other mental disorders such as anxiety or depression.

Applications
More recently these observations about discount functions have been used to study saving for retirement, borrowing on credit cards, and procrastination. It has frequently been used to explain addiction.[26][27] Hyperbolic discounting has also been offered as an explanation of the divergence between privacy attitudes and behaviour.[28] Discount functions have also been used in studies related to individuals with ADHD as a way to measure their impulsivity. Delay discounting has also been used in studies of academic performance, showing that adolescents with higher rates of discount (i.e., a preference for smaller immediate rewards over larger delayed rewards) have lower academic achievement.