Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental condition characterized by an abnormally high activity level and an inability to concentrate. It affects a person's development and ability to carry out everyday tasks, commonly occurring in children before the age of seven. The global prevalence of ADHD is estimated at 5%, with males to females at 3:1, yet under-recognized in girls.
The cause of ADHD is unknown, yet evidence suggests a combination of environmental and genetic factors.
Risk factors for ADHD include prematurity, low birth weight, low paternal education, prenatal smoking, and maternal depression.
ADHD features are part of the normal range of childhood behaviours, yet require diagnosis when these features are adversely affecting the child's life. Typical features include a short attention span, quickly losing interest in tasks, fidgeting, impulsivity, disruptive behavior, poor organisational skills, and acting without thinking.
Differential diagnoses to consider when a child or adult presents with suspected ADHD are anxiety, depression, autism spectrum conditions, childhood trauma, PTSD, personality disorders, oppositional defiant disorder, conduct disorder, learning disabilities, and epilepsy.
ADHD is a clinical diagnosis and should be conducted by a specialist. It is essential for primary care settings to assess how symptoms are affecting the patient.
In school-aged children, enquire about friendships, school and personal safety. In adolescents, be aware of issues that may arise in school, work, relationships, and household tasks such as shopping or chores.
Primary care physicians with the appropriate training may use the Strengths and Difficulties questionnaire or the Conners' rating scale to aid their assessment. For adults, the Diagnostic Interview for ADHD in Adults (DIVA) questionnaire can be useful. These rating scales are not diagnostic, but help obtain structured information to aid diagnosis.
ADHD diagnosis is based on DSM-5 diagnostic criteria (Table 1). For children aged up to 16, six or more symptoms of inattention and six or more symptoms of hyperactivity and impulsivity are required. For those aged 17 and over, only five or more symptoms are needed from each category. The symptoms must occur in multiple settings, have been present for at least six months, and are not better explained by another disorder.
If a child only displays these behaviours at school, but not at home, there is a likely environmental cause. If behaviours only continue for two weeks, then they may be explained by situational causes.
Table 1. DSM-5 diagnostic criteria for ADHD.
The symptoms must occur in multiple settings (e.g. at home and school), have been present for at least six months and are not better explained by another disorder.
For adults, impulsivity may be reflected in drug or alcohol use, forensic history and employment history.
Initially, patients with ADHD should take a period of watchful waiting for up to ten weeks and at the same time practice self-help techniques and simple behavioral management. Establishing a healthy diet and engaging in regular exercise can have significant benefits for their behavior. Families should be referred to an ADHD-focused support program to meet other people with similar experiences, benefit from peer advice, and feel less isolated.
Effective behavior management techniques include reward charts, positive redirection, 1-2-3-reward visuals, and use of self-imposed concentration breaks. Instead of pointing out undesired behavior, the child should be instructed on what they should do. The 1-2-3-reward visuals breaks tasks into three simple steps, allowing the child to track their progress. For example, for bedtime an individual can break the routine into (1) changing into their pajamas, (2) brushing their teeth, (3) getting into bed, and (4) being rewarded with a story.
If symptoms are severe or persist after self-help measures, a referral to child and adolescent mental health services or a specialist paediatrician is necessary.
First-line management for ADHD is an ADHD-focused parent training program. If symptoms are still causing significant issues, medication may be recommended. The primary medication prescribed is methylphenidate. Cognitive based therapy may also be included.
Methylphenidate is a central nervous system stimulant that can cause growth retardation, weight loss, tachycardia, and hypertension. As such, children taking this medication need to have their height, weight, heart rate and blood pressure measured every six months.
Studies suggest that symptoms of ADHD continue into adulthood for as many as 60% of affected individuals, leading to lower educational and employment attainment, poor self-esteem, criminal behaviour, relationship issues, sleep disturbance, substance abuse, road traffic accidents, and self-harm.
