Is ADD Hereditary? (Attention Deficit Disorder)

Is ADD hereditary? Is there a gene for it? Will all my children have it if my son does now? Gina Hozie, Greenwood, SC

Attention deficient disorder, or ADD, is a very common medical condition. Approximately three to five percent of American school-age children have this diagnosis. For reasons unknown, ADD is diagnosed six times more frequently in males than in females. Individuals with ADD may also be hyperactive (attention deficit/hyperactivity disorder or ADHD). Both conditions cause children to have problems in performance and in learning, although they are not necessarily learning disabled. Symptoms of ADD usually become apparent in the elementary school years because of disruptive behavior and difficulty staying on task. Affected children will be more inattentive, impulsive, and easily distracted than other children their age. The specific biologic defect is still unknown, but studies have shown decreased activity in areas of the brain responsible for regulating our impulses, planning and memory abilities. Approximately 70% of children with AD(H)D respond to stimulant medications that target dopamine receptors in these brain regions.

There are probably multiple causes of AD(H)D. We know that these conditions do clearly run in families. About 30% of individuals with AD(H)D have a close relative with this condition. Some studies have shown an increased frequency of other psychiatric disorders, including anxiety and mood disorders, in individuals with AD(H)D and their family members. Additionally, 30% of children with AD(H)D may also have a learning disability, often a reading disability. Adoption and twin studies also support a genetic basis for AD(H)D. The recurrence risk for families to have another child with AD(H)D may be as high as 25%, for each subsequent pregnancy. The individual genes responsible for AD(H)D have not yet been found, but this is currently a very active area of research. Genes that encode certain chemical receptors in the brain are being investigated, as are genes related to the immune system. Even mouse models are being studied to determine genetic factors in this condition.

As with all medical conditions, proper diagnosis is important for individuals who exhibit signs or symptoms of AD(H)D. An educational evaluation is required to determine if a learning disability is contributing to the learning problems. A medical and neurological evaluation is also necessary to rule out other medical conditions that could mimic AD(H)D. An effective treatment plan can then be established to combine proper medical therapy, with specific parenting and teaching strategies, that are optimal for the child. For more information, please contact the Attention Deficit Disorder Association at (305) 587 - 3700.