Again, most researchers suggest that true ADHD is not caused by environmental factors. However, the following environmental factors may exacerbate symptoms of true ADHD, or create ADHD-like symptoms: prenatal and perinatal complications (e.g., low birth weight, fetal distress), prenatal alcohol or tobacco exposure, lead poisoning, pesticides, moderate to severe protein deficiency, head injuries that involve the frontal lobe, allergies, abuse or violent trauma. All of these environmental stressors must be examined more fully to determine their exact link, if any, to ADHD.
Children are not able to respond to environmental stressors in the same way as adults. For example, if adults were faced with severe interpersonal relationship problems, they might read about and use self-help strategies to resolve problems, seek therapy, or leave the relationship. In contrast, children may begin having problems paying attention and monitoring their behavior. These findings emphasize that there are various potential environmental contributors to ADHD-like symptoms that must be considered when evaluating a child for diagnosis. The examination of different situations that create similar behavioral problems clearly demonstrates the importance of an accurate diagnosis.
Some researchers believe that at least part of the reason for the increase in ADHD diagnoses is related to the influence of modern lifestyle changes. These theories are based on the notion that the brains of very young children (i.e., under age 2) are not yet sophisticated enough to accurately process media images. It is thought that viewing media at this age may disrupt the brain's normal developmental process, which is gained through experiences with real people and objects. As a result, introducing artificial images to very young children may result in faulty brain development, inaccurate perceptions of the world, attention deficits, diminished reading ability, and even obesity. Video games, and the fast-cut modern style of music videos and some movies are also thought to be problematic for some individuals. Young children require more time to sort through visual images than do older children and adults, leaving them vulnerable to becoming disoriented and agitated from viewing fast-cut media.
Other professionals believe that frequent exposure to intense lightning-fast visual images can disrupt cognitive functioning by teaching young developing brains to become dependent on excessive stimulation. This experience may train many young people to constantly shift attention from one stimulus to the next, thus making them become easily bored with a more real-world pace. In settings without fast-paced media images (like school or the playground), these children feel under-stimulated, cannot focus on other tasks, and compulsively seek physical activity or increased stimulation. This type of behavior sounds very much like true ADHD, but it is not likely the result of neurological changes, and does not usually meet the DSM criteria for diagnosing ADHD. Although there is no scientific evidence to date showing that media exposure causes ADHD, many professionals agree that this type of media may at least compound the attention difficulties of individuals with ADHD.
Frequent exposure to violent images has also been hypothesized as a contributing factor to ADHD symptoms. Developing brains that are bombarded by violent images may be flooded with high levels of cortisol (a stress hormone) in response to fear and emotional distress. Some studies suggest that high levels of cortisol can create permanent changes in the brain. Whether or not these brain changes can result in true ADHD or simply symptoms similar to ADHD has yet to be determined.
Even if viewing violent images does not cause ADHD, this type of media can cause high levels of distress, disorientation and faulty information processing skills. Research solidly supports the notion that young children need to be shielded from much of today's violent content. As a child ages and becomes increasingly mature, violent content can be gradually introduced, if necessary. Given that TV is a relatively recent phenomenon, we are only recently identifying the unintended consequences of excessive media exposure for all ages.
Although research has clearly shown that nutrition and eating habits do not cause ADHD, there are indications that children with this disorder are metabolically different from others. However, there have not yet been a large number of systematic research studies in this area. Too much sugar, too many refined foods, too many artificial foods and food substances, too few fruits and vegetables, red food dyes, and a deficiency in Omega-3 fatty acids have all been implicated as potential factors that can aggravate ADHD symptoms in some children.
The Feingold Diet involves removing salicylates (compounds found in plants that are used as preservatives in processed food products) artificial colors and flavors, and certain synthetic preservatives from children's diets. Originally developed as a method to identify food allergies, changes in behavior were noted in children on the diet. Artificial preservatives, colors, etc. are in almost everything we eat today. Proponents of the Feingold diet suggest that the buildup caused by frequent ingestion of these products may be part of the reason behind dramatic increase in the prevalence of ADHD.
Children who have been breast fed at least six months are less likely to develop ADHD than children who are bottle fed. Some researchers speculate that the presence of Omega-3 fatty acids (essential fats that promote healthy brain development) in breast milk plays a protective role, so many manufacturers now put these acids into infant formulas. It is also thought that a lack of Omega-3 fatty acids in older children's diets can exacerbate existing ADHD or trigger the development of ADHD-like symptoms. More research is necessary to clarify whether early intake of sufficient amounts of Omega-3 fatty acids can alter the physiological changes that are apparent in children diagnosed with ADHD.
Since ADHD is present in individuals from a very early age, understanding it's origin is quite challenging. The fact that most children are identified at a later age reduces the possibility of conducting meaningful research with very young children who have ADHD. In contrast, a great deal is known about school aged children with ADHD. The diagnosis appears to result in similar experiences for most ADHD children in the primary social arenas of their lives.