Attention-Deficit/Hyperactivity Disorder Combined in Adults

This subtype is different from the other two subtypes of ADHD in that one set of symptoms does not predominate. ADHD, Combined Presentation is approximately twice as prevalent in adult men as adult women.

ADHD is characterized by two main categories of symptoms:

• Inattention, which refers to difficulty paying attention to and carefully completing a given task, particularly in situations that require continued concentration or mental effort.
• Hyperactivity-impulsivity, which means having an unusually high level of activity and difficulty inhibiting impulses. Motor symptoms of hyperactivity maybe less prominent in adulthood, but difficulties persist with restlessness and impulsivity.

The Combined Presentation of ADHD is diagnosed if five or more symptoms of hyperactivity/impulsivity, and at least five symptoms of inattention, have been present for the past six months:

Inattention symptoms:

• Often fails to give close attention to details or makes careless mistakes on schoolwork or other activities
• Often has difficulty holding attention on tasks or leisure activities
• Often does not seem to listen when spoken to directly
• Often does not follow through on instructions and fails to finish errands or chores
• Often has difficulty with organization
• Often avoids or dislikes tasks that require continued mental effort
• Often loses necessary materials
• Is often easily distracted
• Is often forgetful in daily activities

Hyperactivity/impulsivity symptoms:

• Often fidgets with or taps hands or feet, or squirms in seat
• Often leaves seat in situations when remaining seated is expected
• Often feel restless
• Often unable to take part in leisure activities quietly
• Is often "on the go" acting as if "driven by a motor"
• Often talks excessively
• Often blurts out an answer before a question has been completed
• Often has trouble waiting his/her turn
• Often interrupts or intrudes on others (e.g., butts into conversations)

In order to meet criteria for ADHD, Combined Presentation, five or more symptoms of inattention and five or more symptoms of hyperactivity/impulsivity must be present in adults. These symptoms must be present for at least six months and inappropriate for the person's developmental level. Additionally, the following conditions must be met:

• Several symptoms were present before age 12
• Several symptoms are present in two or more settings, such as at work, home, and in social interactions
• Symptoms clearly interfere with or reduce the quality of the individual's work or social functioning
• Symptoms are not better explained by another psychiatric condition (for example, an anxiety or mood disorder) or occur only during the course of schizophrenia or another psychotic disorder

Historically, ADHD was considered to be a childhood disorder that most people outgrew. However, recent data suggest that symptoms of ADHD continue into adulthood in up to half of individuals with childhood ADHD. Although research on adult ADHD is reduced compared to childhood ADHD, there is growing evidence that ADHD may present somewhat differently in adulthood.

ADHD is characterized by deficits in neurocognitive processes. Specifically, individuals with ADHD have difficulty with executive function, which includes processes that are important for regulating attention and behavior, such as attentional control, inhibitory control, cognitive flexibility, and planning.

There are many known causes of ADHD, including a strong genetic component. Genetics appears to be the principal cause of ADHD, likely accounting for up to approximately 75% of all cases. In a smaller percentage of cases, ADHD may arise from early brain injuries, low birth weight, exposure to environmental toxins during gestation (e.g., maternal smoking) or youth (such as lead). Research does not support the claim that ADHD is a result of food additives, preservatives, or sugar.

In adults, ADHD frequently occurs with other psychiatric conditions, including mood disorders, anxiety, learning disorders, and substance use disorders. In fact, a large national study found 51% of adults with ADHD suffered from co-morbid anxiety and 32% suffered from co-morbid depression. Because of the amount of overlapping symptoms with other disorders, diagnosing ADHD can be complicated.