ADHD Myths

ADHD is caused by too much sugar (or aspartame, or preservatives, etc.) in the diet.

Among the causal myths about ADHD, some have targeted common dietary substances, including sugar, aspartame (an artificial sweetener), various food colorings, and preservatives. However, the role of dietary factors has been investigated for three decades without producing evidence of a relationship. In 1982, at a consensus conference convened by the National Institutes of Health, researchers reviewed over 20 studies and found that no relationships existed between dietary variables and the symptoms of ADHD. Neither those studies nor others conducted since that time have yielded any evidence of a relationship between the consumption of specific substances and the symptoms of ADHD (Hoover & Milich, 1994; Shaywitz et al., 1994; Wolraich et al., 1994; Wolraich, Milich, Stumbo, & Schultz, 1985).

When a complete causal explanation of ADHD is established, it will not be so simple as the effects of ingesting sugar or artificial sweetener. Nor is it likely that it will involve a single cause. Just as a number of causal elements have been found for medical conditions such as heart and bone diseases, scientists believe multiple factors will ultimately be identified as causes of ADHD (LaHoste et al., 1996).

ADHD is caused by poor parenting.

Although some members of the public have stated that poor child-raising practices are responsible for causing ADHD, research has found no evidence to support this myth. However, research has revealed that in a significant number of cases, parents' genetic contributions to their children may "cause" ADHD. One study that investigated the role of genetic inheritance found that when one parent had ADHD, the risk to his or her offspring was 57% (Biederman et al., 1995). Although researchers have not identified a genetic link in all cases of ADHD, they have found that individuals with a family history of the disorder are more likely to have it themselves. This risk may be increased when combined with factors that parents may or may not be able to control, including prenatal health and environmental toxins (Milberger, Biederman, & Faraone, 1994; Sprich-Buckminster, Biederman, Milberger, Faraone, & Lehman, 1993).

Among the studies that have investigated the heritability of ADHD several have found that the parents and siblings of children diagnosed with ADHD are much more likely to have the disorder themselves (Cantwell, 1972; Biederman et al., 1992; Deutsch, Matthysse, Swanson, & Farkas, 1990; Faraone et al., 1993; Hechtman, 1994). Studies of twins have found that if one identical twin has ADHD, the chances have been estimated at 80-90% that the other twin will have it as well (Hechtman, 1994; Levy, Hay, McStephen, Wood, & Waldman, 1997). Findings of the same study indicated that if one non-identical twin has ADHD, there is a 30% chance that the sibling twin will have it as well. Other studies have demonstrated genetic transmission factors in children who have both ADHD and learning disabilities (Faraone et al., 1993; Gilger, Pennington. & DeFries, 1992; Gillis, Gilger, Pennington, & DeFries, 1992; Semrud-Clikeman et al., 1992).

Researchers are currently investigating the relationship of multiple genetic factors to ADHD. In 1995, a dopamine-related gene was linked to novelty-seeking behavior (Cook et a1., 1995; Benjamin et al.,1996; Ebstein et al., 1996). Two years later, researchers confirmed that it is involved in some cases of ADHD (Gill, Daly, Heron, Hawi, & Fitzgerald, 1997; Swanson et al., 1997).

Although a causal link has not been demonstrated between parenting practices and ADHD, this is not necessarily the case for two other conditions that co-occur at a high rate of frequency with ADHD. Studies have indicated that two disorders associated with significantly difficult and negative behaviors, Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD), may in some cases be connected with parents' behavior. The behaviors associated with ODD and CD appear to be precipitated or exacerbated by some parents' communication styles and child-rearing practices (Sprich-Buckminster et al., 1993).