Attention-Deficit/Hyperactivi... Health Article

Causes and symptoms

The causes of AD/HD are not specifically known. However, it is a neurologically based disease that may be genetic. Children with an AD/HD parent or sibling are more likely to develop the disorder themselves. Although the exact cause of AD/HD is not known, an imbalance or deficiency of certain neurotransmitters—the chemicals in the brain that transmit messages between nerve cells—is believed to be the mechanism behind AD/HD symptoms.

A widely publicized study conducted by Dr. Ben Feingold in the early 1970s suggested that allergies to certain foods and food additives caused the characteristic hyperactivity of AD/HD children. By eliminating the food allergen, the premise was that AD/HD characteristics would disappear. Although some children may have adverse reactions to certain foods and food additives that can affect their behavior, carefully controlled follow-up studies have uncovered no link between food allergies and AD/HD. Another popularly held misconception about food and AD/HD is that the consumption of sugar causes the hyperactive behavior in an AD/HD child. Again, studies have shown no link between sugar intake and AD/HD. (In a recent study conducted by the National Institute of Mental Health, the level of glucose use in the brain was actually lower in individuals with AD/HD. Since glucose is the main source of fuel for the brain, this is a significant finding.) Finally, parenting style is not a cause for AD/HD. While certain parenting skills and/or deficiencies can affect the environment of an AD/HD child and, as a result, exasperate or help manage the characteristics of AD/HD, it appears that neurological issues are the primary causal agents at play.

In order to diagnose AD/HD, psychologists and other mental health professionals typically use the criteria listed in the DSM-IV. DSM-IV requires the presence of at least six of the following symptoms of inattention, or six or more symptoms of hyperactivity and impulsivity combined.

Inattention:

• fails to pay close attention to detail or makes careless mistakes in schoolwork or other activities
• has difficulty sustaining attention in tasks or activities
• does not appear to listen when spoken to
• does not follow through on instructions and does not finish tasks
• has difficulty organizing tasks and activities
• avoids or dislikes tasks that require sustained mental effort (e.g., homework)
• is easily distracted
• is forgetful in daily activities

Hyperactivity:

• fidgets with hands or feet or squirms in seat
• does not remain seated when expected to
• runs or climbs excessively when inappropriate (in adolescence and adults, feelings of restlessness)
• has difficulty playing quietly
• is constantly on the move
• talks excessively

Impulsivity:

• blurts out answers before the question has been completed
• has difficulty waiting for his or her turn
• interrupts and/or intrudes on others

Of those symptoms, AD/HD can be categorized further by three subtypes. Each subtype exhibits particular behaviors that make up the general symptoms of a child with AD/HD. They are:

AD/HD predominantly inattentive type (AD/HD-I)

• is disorganized
• is easily distracted
• is forgetful
• has unsustained attention
• has difficulty following instructions
• appears to have poor listening skills
• makes careless mistakes

AD/HD predominantly hyperactive-impulsive type (AD/HD-HI)

• fidgets
• is unable to engage in quiet activity
• is interruptive or intrusive
• cannot remain seated
• speaks out of turn
• climbs or runs about inappropriately
• talks excessively

AD/HD combined type (AD/HD-C) is a combination of the symptoms exhibited by the other two subtypes (inattentive type and hyperactive-impulsive type). Also, for a complete diagnosis, DSM-IV requires that some symptoms develop before age seven, and that they significantly impair functioning in two or more settings (e.g., home and school) for a period of at least six months.