Substance abuse and addiction are serious health problems in the United States, costing the US economy over $480 billion each year.  To name a few statistics, 10-22% of car crashes are drug-related (often involving alcohol as well).  50% of arrests for major violent crimes are due to drugs (murder, theft, assault, etc.).  11 to 30% of all cancer deaths are due to tobacco usage.  

Besides the economic cost, there is the emotional burden on friends and family members, and possible disruption in school. Child abuse and domestic violence may occur as a result of addiction.  Clearly, the consequences of substance abuse and addiction can be severe.   But, what is substance abuse? And, when does drug abuse become drug addiction?  

What is substance abuse?
The definition of substance abuse can be extremely tricky. In general, substance abuse occurs when a person takes a chemical to purposely alter mood. Most all drugs interfere with the brain's ability to process 'rewards' or positive feelings.  During substance abuse, drugs mimic the brain's own chemicals OR overuse the brain's ability to recognize 'rewards.'   This is why the brain can be fooled into spending additional time on the drug, because of the unusually high amplification of positive or good feelings, the 'reward.'  

Substance abusers may forgo normal, healthy life habits (spending time with friends; eating; etc.) in lieu of using the substance (or drug).   The extent of abuse depends on the age of the person and/or the quantity of chemical consumed.  

What is drug addiction?
A person addicted to a substance - any substance - experiences a strong psychological urge to consume a drug, chemical or mind - altering substance. This urge may be so strong that it is viewed as a 'need.' During addiction, physical dependence on the drug or substance may or may not be present and withdrawal symptoms may occur if the substance is not consumed.  

Drugs interfere with the normal process of understanding and receiving information in the brain. In fact, addiction is a serious, complicated brain disease in which a substance is desired, sought, and used even though the consequences may be entirely negative to both the individual, and to broader society.   Furthermore, addiction is chronic disease; relapses are common, even years after chemicals have been removed from the body.

Neurotransmitters: the science of addiction
Doctors have identified the neurotransmitter "dopamine" as a naturally occurring brain chemical that is linked to emotion and motivation.  During drug use, dopamine can be over-produced or may not be metabolized in a normal way, and creates an intense sense of euphoria or pleasure.  Over time, the brain itself reacts to these higher than normal levels of dopamine in the brain.  The brain may respond by either producing less dopamine itself, or by reducing the ability to receive as much dopamine.  The result?  A person has to use more and more of the drug in order to feel 'normal' or in order to get the previous high.  

Tolerance is predictable outcome of drug use. When a body is tolerant to a drug, it requires a higher drug dosage to receive the same effects.  The brain responds to the abnormal levels neurotransmitters (chemicals) by rewiring itself.  Learning processes, judgment, decision making, etc. can all be affected. Therefore, addicts experience intense drug cravings that compel them to seek out and use drugs, despite the negative consequences.  Now addicted, the substance abuser cannot just quit, of his own free will, but rather requires a complicated process of treatment that may rely on multiple strategies.

Who is at risk of addiction?  What risk factors can contributes to the development of drug addiction? Keep reading here for more information on causes of drug addiction.