No one is born addicted or destined for a life of dependence and addiction. With many diseases, the more risk factors a person has, the greater the chances of contracting the disease. For example, heart disease runs in families. Why do some people become addicted and others don't? Family studies that include identical twins, fraternal twins, adoptees, and siblings suggest that up to half of a person's risk of becoming addicted to nicotine, alcohol, or other drugs depends on their genetic makeup.
Finding the biological basis for this risk is an important avenue of research for scientists trying to solve the problem of drug addiction. Addiction is due 50 percent to genetic predisposition and 50 percent to poor coping skills. This has been confirmed by numerous studies. One study examined 861 identical twin couples and 653 fraternal (non-identical) twin couples.
When an identical twin was addicted to alcohol, the other twin had a high chance of being addicted. But when a non-identical twin was addicted to alcohol, the other twin didn't necessarily have an addiction. Based on the differences between identical and non-identical twins, the study showed that 50-60 percent of addiction is due to genetic factors. Drug use can also cause the baby to be born dependent on drugs and have to suffer withdrawal at birth.
Babies who were regularly exposed to opioids in utero may develop neonatal withdrawal syndrome (NAS), a set of problems that occurs because the baby is suffering opioid withdrawal after birth. For example, by studying twins and children who were born to addicted parents but were later adopted by non-addicted families, scientists have found that their genes are responsible for about half of their chances of becoming addicted. Some children are born with so many risk factors for addiction that it seems that they are destined to become addicted.