The official definition of Attention Deficit Hyperactivity Disorder (ADHD) as it appears in the Diagnostic and Statistical manual of the American Psychiatric Association is: ADHD is a disorder that can include a list of nine specific symptoms of inattention and nine symptoms of hyperactivity/impulsivity. 


Individuals with ADHD may know what to do but do not consistently do what they know because of their inability to efficiently stop and think prior to responding, regardless of the setting or task. 


Characteristics of ADHD have been demonstrated to arise in early childhood for most individuals. This disorder is marked by chronic behaviors lasting at least six months with an onset often before seven years of age. At this time, four subtypes of ADHD have been defined. These include the following: 


1. ADHD Inattentive type is defined by an individual experiencing at least six of the following
characteristics: 


a. Fails to give close attention to details or makes careless mistakes 
b. Difficulty sustaining attention 
c. Does not appear to listen 
d. Struggles to follow through on instructions 
e. Difficulty with organization 
f.  Avoids or dislikes requiring sustained mental effort 
g. Often loses things necessary for tasks 
h. Easily distracted 
i. Forgetful in daily activities 


2. ADHD hyperactive/impulsive type is defined by an individual experiencing six of the following characteristics: 


a. Fidgets with hands or feet or squirms in seat 
b. Difficulty remaining seated 
c. Runs about or climbs excessively (in adults may be limited to subjective feelings of restlessness) 
d. Difficulty engaging in activities quietly 
e. Acts as if driven by a motor 
f. Talks excessively 
g. Blurts out answers before questions have been completed 
h. Difficulty waiting in turn taking situations 
i. Interrupts or intrudes upon others 


3. ADHD combined type is defined by an individual meeting both sets of attention and hyperactive/impulsive criteria. 


4. ADHD not otherwise specified is defined by an individual who demonstrates some characteristics but an insufficient number of symptoms to reach a full diagnosis. These symptoms, however, disrupt everyday life. 


The majority of adults with ADHD have been described as experiencing symptoms very similar to the problems experienced by children. They are often restless, easily distracted, struggle to sustain attention, are impulsive and impatient. They have been described as experiencing problems with stress intolerance leading to greater expressed emotion. Within the workplace they may not achieve vocational positions or status commensurate with their siblings or intellectual ability. 


Children and adults who have ADHD exhibit degrees of inattention or hyperactivity/impulsivity that are abnormal for their ages. This can result in serious social problems, or impairment, of family relationships, success at school or work or in other life endeavors. 


Children and adults can exhibit other psychiatric disorders (medically known as comorbidity), along with their ADHD symptoms. Most commonly, these include oppositional defiant or conduct disorder, along with or separate from internalizing disorders, such as anxiety and depression. 


Other definitions have existed, such as that for Attention Deficit disorder, or ADD. These use different labels for the same conditions and can be interchanged with ADHD. For the purposes of this fact sheet, however, we will continue to use ADHD. 


Statistics: 
About 1% to 3% of the school-aged population has the full ADHD syndrome, without symptoms of other disorders. Another 5% to 10% of the school-aged population have a partial ADHD syndrome or one with other problems, such as anxiety and depression present. 


Another 15% to 20% of the school-aged population may show transient, subclinical, or masquerading behaviors suggestive of ADHD. A diagnosis of ADHD is not warranted if these behaviors are situational, do not produce impairment at home and school, or are clearly identified as symptoms of other disorders. 


Gender and age affect the ways in which people with ADHD express their symptoms. Boys are about three times more likely than girls to have symptoms of ADHD. Symptoms of ADHD decrease with age, but symptoms of associated features and related disorders increase with age. Between 30% and 50% of children still manifest symptoms into adulthood. 


Causes: 


Experts have investigated genetic and environmental causes for ADHD. Some children may inherit a biochemical condition, which influences the expression of ADHD symptoms. Other children may acquire the condition due to abnormal fetal development, which has subtle effects on brain regions that control attention and movement. 


Recently, scientists have uncovered research based on brain imaging to localize the brain areas involved in ADHD and have found that areas in the frontal lobe and basal ganglia are reduced by about 10 percent in size and activity in ADHD children. 


Recent research based on genetic mechanisms has focused on dopamine as the primary neurotransmitter involved in ADHD. Dopamine pathways in the brain, which link the basal ganglia and frontal cortex, appear to play a major role in ADHD. 


Commonly suspected causes of ADHD have included toxins, developmental impairments, diet, injury, ineffective parenting and heredity. 


How is ADHD diagnosed? 


While there is no biological or psychological test that makes a definitive diagnosis of ADHD, a diagnosis can be made based on one's clinical history of abnormality and impairment. 


An evaluation for ADHD will often include assessment of intellectual, academic, social and emotional functioning. Medical examination is also important to rule out low occurring but possible causes of ADHD like symptoms (e.g., adverse reaction to medications, thyroid problems, etc.). The diagnostic process must also include gathering data from teachers as well as other adults who may interact on a routine basis with the individual being evaluated. 


It is even more important in the ADHD adult diagnostic process to obtain a careful history of childhood, academic, behavioral and vocational problems. With the increased recognition that ADHD is a disorder presenting throughout the life span, questionnaires and related diagnostic tools for the assessment of adult ADHD have been standardized and are increasingly available. 


ADHD diagnoses are based on a person having three different symptoms. The full syndrome is diagnosed when at least nine symptoms from both sets of subtypes (above) are present. Partial syndromes, which are predominantly inattentive or hyperactivity/impulsivity subtypes, are diagnosed when six or more symptoms are present from just one set. 


Treatment: 


There are two modalities of treatment that specifically target symptoms of ADHD. One uses medication and the other is a non-medical treatment with psychosocial interventions. The combination of these treatments is called multimodality treatment. 


Treating ADHD in children requires a coordinated effort between medical, mental health and educational professionals in conjunction with parents. This combined set of treatments offered by a variety of individuals is referred to as multi-modal intervention. A multi-modal treatment program should include: . Parent training concerning the nature of ADHD as well as effective behavior management strategies . An appropriate educational program . Individual and family counseling, when needed, to minimize the escalation of family problems . Medication when required 


Psychostimulants are the most widely used medications for the management of ADHD symptoms. At least 70% to 80% of children and adults with ADHD respond positively to psychostimulant medications. 

Stimulant medications have been used to treat the cognitive and behavioral symptoms of ADHD for more than 50 years. A study by Wilens and Biederman (1997) summarized the findings of controlled trials validating the use of these medications. Treatment with stimulants is beneficial in about 80% of children with ADHD. 

Behavior modification techniques have been used to treat the behavioral symptoms of ADHD for more than a quarter of a century. A summary of the literature on trials that have validated the efficacy of this approach shows that, in many cases, behavior modification alone has not been sufficient to address severe symptoms of ADHD. 

Classroom success for children with ADHD often requires a range of interventions. Most children with ADHD can be taught in the regular classroom with either minor adjustments in the classroom setting, the addition of support personnel, and/or special education programs provided outside of the classroom. The most severely affected children with ADHD often experience a number of occurring problems and require specialized classrooms. 

Laws passed during the last five years have mandated educational interventions for children with ADHD. Today, modifications and special placements in public school settings are part of treatment of ADHD. The coordination of school-based interventions with medical interventions has become possible (but remains difficult) due to these changes in educational law regulations.