At present, there is no scientific evidence that demonstrates media exposure causes ADHD. However, some researchers believe that the rise of ADHD diagnoses may be partially related to the influence of modern media and technologies. Why might this be so? The normal development of children's brains is gained through experiences with real people and objects. The brains of very young children (age 2 or less) are not adequately developed to accurately process media or screen images. As a result, introducing artificial images to very young children may cause inaccurate perceptions of the world; abnormal brain development; attention deficits; diminished reading ability; and even obesity (Kirkorian, et al., 2008).
The visual speed of video games, and modern, fast-paced, audio-visual entertainment may also be problematic. Young children require more time to sort through visual images than do older children and adults. This leaves them vulnerable to becoming disoriented and agitated from viewing high-speed media images.
Some professionals believe that frequent exposure to intense, lightning-fast visual images can disrupt cognitive functioning by allowing young developing brains to become dependent on excessive stimulation. As a result, children may become easily bored with the pace of the real world. In a similar manner, our experiences with computers and the Internet have taught us to expect an immediate answer within seconds of asking a question. Once accustomed to such speed, settings without this rapid pace (like school or the playground) may leave children feeling under-stimulated and unable to sustain focus beyond a few seconds. While this would apply to all children, it would make things worse for someone who already has pre-existing attention problems.
Frequent exposure to violent images has also been implicated in ADHD. Exposure to violent images increases cortisol levels (a stress hormone) in response to fear and emotional distress. Developing brains that are bombarded by violent images may be flooded with high levels of cortisol. Some studies suggest that high levels of cortisol can create permanent changes in the brain. Whether these brain changes can affect ADHD symptoms has yet to be determined. Nonetheless, viewing violent images can cause high levels of distress, disorientation, and faulty information-processing. Research solidly supports the notion that young children need to be shielded from much of today's violent content. As children grow and mature, violent content can be gradually introduced, with fewer negative effects. Given that TV is a relatively new phenomenon, we are only recently identifying the unintended consequences of excessive media exposure for all ages.