Some factors that affect attention span in adults are attention deficit hyperactivity disorder (ADHD), fatigue, technology, and the side effect of certain medications. Millions of people live with ADHD, a disorder that can severely affect attention span in adults and children. Fatigue is another common factor and its symptoms are sometimes mistaken for ADHD or other chronic disorders and mental health problems. In addition, many studies show that spending a lot of time watching television on a frequent basis can shorten attention span. A shortened attention span is also a side effect of some prescription drugs and stimulants.
Attention deficit hyperactivity disorder is a common factor that influences attention span in adults. People who have ADHD have difficulty paying attention and may act on impulses most other people can dismiss. This problem is usually diagnosed in children when it is most obvious, and some evidence shows that it might run in families. Around half the children who develop ADHD are believed to have the same problems as an adult, but adults usually have better control over themselves and some capability of masking symptoms.
An inability to pay attention for long can also be caused by mental fatigue. Depression, anxiety, and poor sleep are some situations in which mental fatigue is likely to develop. Mental fatigue might also be accompanied by physical fatigue, but having physical fatigue does not necessarily mean a person exercised or worked themselves to exhaustion. Physical fatigue can be caused by many of the same things that cause mental fatigue.
Some studies show that toddlers who watch television have a decreased attention span in their later years. In addition, children continue to have trouble throughout grade-school if three or more hours of television is watched on a regular basis. The same study reported that college students who watch television seemed to experience even more problems paying attention than the preteens and early teenagers. Experts recommend two hours or less television per day, no matter the age of the person — but the subject matter of a television show should be taken into consideration. In general, however, less is better.
Prescription medication and drug abuse can also affect attention span in adults. For example, shortened attention span is a listed side effect of several medications prescribed by doctors. Drugs that act as stimulates are sometimes known to cause a shortened attention span also. Different people can be affected by the same drug in different ways, however, so an adult might not experience this particular effect.