At the crux of many scientific debates is the age-old “nature versus nurture” question. Basically, everyone wants to know why people do what they do. Is it because they're “born that way” or because outside influences shape them?

The jury's still out on a decisive answer, but so far it looks like people's behaviors are determined by both natural and environmental (nurture-related) factors. That's certainly true for defiant behavior, though you may find your child is more influenced by one type of factor than another.

Children Whose Parents Use Drugs and Alcohol

Drugs and alcohol are two factors that can influence defiant behavior and a host of other problems. If your child was a victim of Fetal Alcohol Syndrome or was exposed to drugs in utero or in early childhood, he might have impaired brain functioning that can be a factor in his defiant behavior.

Drugs and alcohol impair brain functioning in two ways: directly and indirectly. The substances can act directly by altering the brain's natural chemistry, slowing down its ability to process information — not a good way for healthy thinking to develop. They act indirectly while a child is “under the influence,” because he's losing precious time to absorb crucial information and strengthen neural pathways.

Kids Who Abuse Substances

The same two tragic results occur when kids ingest substances on their own. As kids enter high school, the likelihood that they or their friends have tried alcohol or drugs increases. According to a study in the Bureau of Justice Statistics, about two-thirds of high school seniors have used alcohol at least once in the past year, and nearly a third have used marijuana in the same time frame.

While public awareness of these drugs has increased, it's easy to shrug off erratic behavior as “just a phase.” If you think some strange behavior could be influenced by substance abuse (including alcohol), take action immediately. Begin by talking to your child and increasing supervision, and don't hesitate to take your child to the hospital if you think a medical emergency is occurring.

Defiant behavior may be a factor in your child's drug use, or drug use may be a factor in defiant behavior. Either way, drugs pose a much more immediate threat to your child's well-being than defiant behavior in and of itself, so don't look the other way.

Oppositional Defiance Disorder

Kids can be born with a predisposition to ODD, so ODD can be a natural cause for defiant behavior. Briefly, ODD is a condition that interferes with a kid's ability to function, has been going on for quite some time, and can is characterized by a short temper, frequent defiance of authorities and rules, annoying behavior, and a spiteful or angry attitude. You'll find more detailed information on ODD in Chapter 4.

Organic (Brain) Issues

Defiant behavior can also stem from impaired brain functioning. A head injury, learning disability, or emotional or cognitive delay — anything that interferes with normal thought processes — can lead to defiant behavior.

Many people are surprised to learn that trauma can lead to impaired brain functioning. Anxiety, post-traumatic stress disorder (PTSD), depression, and other conditions resulting from trauma or violence can throw an adult for a loop, so imagine what they can do to a kid's ability to function and develop. Many people underestimate the debilitating nature of impaired brain functioning and conditions like these, insisting that the child “snap out of it” and “stop licking his wounds.” This old-school tough talk ignores the lasting impact that a few years of depression can have on a child's life. What your parents or grandparents may have described as dealing with tragedy and moving on may actually have been ignoring tragedy and burying it in years of silent heartache instead.