Addiction is hard to understand. If someone has a bad habit that is lifethreatening why don’t they just stop? Addiction comes in many varieties. Excessive eating, gambling, shopping, drug abuse, and smoking are a few examples of addiction. Scientists have found that addictive behavior is difficult to control because ‘addictive’ activities apparently hijack the brain’s reward mechanisms.
Neurons in the reward pathway make us feel good when they release the neurotransmitter dopamine at a synapse—a small gap between two neurons. The dopamine acts as a transmitter, in turn stimulating the following neuron by binding to specialized receptors. Addictive substances hijack this system by increasing the amount of dopamine in the synapse. (There is an ins diagram of this process on Time Magazines’ website).
Research suggests that there may be a genetic predisposition to addiction. There is no such thing as an ‘addiction gene.’ However, some people do carry a combination of genes that make them more susceptible to addictive behavior. Environmental factors also play a role in whether addictive behavior is expressed or not.
Drug abuse is commonly related to criminal or violent activity. For example, according to the ONDCP Drug Policy Fact Sheet, “Data collected from male arrestees in 1998 in 35 cities showed that the percentage testing positive for any drug ranged from 42.5 percent in Anchorage, Alaska, to 78.7 percent in Philadelphia, Pennsylvania. Female arrestees testing positive ranged from 33.3 percent in Laredo, Texas, to 82.1 percent in New York, New York.”
It's unreasonable to claim that criminals are genetically predisposed to addiction and therefore abuse drugs. It's not my useful to claim that drug abuse leads people to commit violent crimes. However, what is known about addiction in the brain does suggest that perhaps some of these individuals would benefit from treatment for addiction in addition to legal prosecution for their crimes.