Signs and symptoms
Inattention, hyperactivity (restlessness in adults), disruptive behavior, and impulsivity are common in ADHD. Academic difficulties are frequent as are problems with relationships. 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.
To be diagnosed per DSM-5, symptoms must be observed in multiple settings for six months or more and to a degree that is much greater than others of the same age. They must also cause problems in the person's social, academic, or work life. Based on the presenting symptom ADHD can be divided into three subtypes: predominantly inattentive, predominantly hyperactive-impulsive, and combined type.
An individual with inattention may have some or all of the following symptoms:
• Be easily distracted, miss details, forget things, and frequently switch from one activity to another
• Have difficulty maintaining focus on one task
• Become bored with a task after only a few minutes, unless doing something enjoyable
• Have difficulty focusing attention on organizing and completing a task or learning something new
• Have trouble completing or turning in homework assignments, often losing things (e.g., pencils, toys, assignments) needed to complete tasks or activities
• Not seem to listen when spoken to
• Daydream, become easily confused, and move slowly
• Have difficulty processing information as quickly and accurately as others
• Struggle to follow instructions
An individual with hyperactivity may have some or all of the following symptoms:
• Fidget and squirm in their seats
• Talk nonstop
• Dash around, touching or playing with anything and everything in sight
• Have trouble sitting still during dinner, school, doing homework, and story time
• Be constantly in motion
• Have difficulty doing quiet tasks or activities
These hyperactivity symptoms tend to go away with age and turn into "inner restlessness" in teens and adults with ADHD. An individual with impulsivity may have some or all of the following symptoms:
• Be very impatient
• Blurt out inappropriate comments, show their emotions without restraint, and act without regard for consequences
• Have difficulty waiting for things they want or waiting their turns in games
• Often interrupt conversations or others' activities
People with ADHD more often have difficulties 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 ADHD have attention deficits which cause difficulty processing verbal and nonverbal language which can negatively affect social interaction. They also may drift off during conversations, and miss social cues. Difficulties managing anger are more common in children with ADHD as are poor handwriting and delays in speech, language and motor development. Although it causes significant impairment, particularly in modern society, many children with ADHD have a good attention span for tasks they find interesting.
Associated disorders
In children ADHD occurs with other disorders about ⅔ of the time. Some commonly associated conditions include:
• Learning disabilities have been found to occur in about 20–30% of children with ADHD. Learning disabilities can include developmental speech and language disorders and academic skills disorders. ADHD, however, is not considered a learning disability, but it very frequently causes academic difficulties.
• Tourette syndrome has been found to occur more commonly in the ADHD population.
• Oppositional defiant disorder (ODD) and conduct disorder (CD), which occur with ADHD in about 50% and 20% of cases respectively. They are characterized by antisocial behaviors such as stubbornness, aggression, frequent temper tantrums, deceitfulness, lying, and stealing. About half of those with hyperactivity and ODD or CD develop antisocial personality disorder in adulthood. Brain imaging supports that conduct disorder and ADHD are separate conditions.
• Primary disorder of vigilance, which is characterized by poor attention and concentration, as well as difficulties staying awake. These children tend to fidget, yawn and stretch and appear to be hyperactive in order to remain alert and active.
• 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.
• Anxiety disorders have been found to occur more commonly in the ADHD population.
• Obsessive-compulsive disorder (OCD) can co-occur with ADHD and shares many of its characteristics.
• Substance use disorders. Adolescents and adults with ADHD are at increased risk of developing a substance use problem. 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.
• 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.
• 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.
There is an association with persistent bed wetting, language delay, and developmental coordination disorder (DCD), with about half of people with DCD having ADHD. The language delay in people with ADHD can include problems with auditory processing disorders such as short-term auditory memory weakness, difficulty following instructions, slow speed of processing written and spoken language, difficulties listening in distracting environments e.g. the classroom, and weakness in reading comprehension.