Attention Deficit Hyperactivity Disorder (ADHD) is a problem with attention or concentration capacity in children receding fast.

ADHD includes over-activity, impulsivity, or a combination of all. It is the most commonly studied and diagnosed psychiatric disorder in children, affecting about 3 to 5 percent of children globally and diagnosed in about 2 to 16 percent of school aged children.

A study by the Harvard School of Public Health's Center for Global Tobacco Control in Boston revealed that children exposed to second-hand smoke or passive smoking are at higher risk of developing attention-deficit/hyperactivity disorder, said a lomalinda.patch report.

They're in a developmental stage and their body is growing, potentially putting them at greater risk of disruptions to their brains than adults, said study co-author Hillel R. Alpert, a research scientist at the Center.

Although the study does not establish the fact that tobacco smoke can harm children's brains, or does not indicate as to how much smoke is too much, it does add to the evidence that children are vulnerable to the effects of smoke exposure, according to the School of Public Health center.

People with ADHD often act and think a little different, according to information provided by the Loma Linda University Medical Center.

They may have trouble in school because they get distracted easily, Loma Linda officials said in the release. They may feel bored all the time for no simple reason, lose things, say or do whatever is on their mind at the time without thinking, and interrupt when other people are talking.

Just about everyone has trouble concentrating or paying attention in class from time to time, Loma Linda officials said. But for teens with attention deficit hyperactivity disorder, symptoms like being unable to pay attention and follow instructions can cause problems at school and in many other areas of their lives.