What is drug addiction?

Addiction is defined as a chronic, relapsing disorder characterized by compulsive drug seeking, continued use despite harmful consequences, and long-lasting changes in the brain. It is considered both a complex brain disorder and a mental illness. Addiction is the most severe form of a full spectrum of substance use disorders and is a medical illness caused by repeated misuse of a substance or substances. 

What is the difference between physical dependence, tolerance, and addiction?

Physical dependence can occur with the regular (daily or almost daily) use of any substance, legal or illegal, even when taken as prescribed. It occurs because the body naturally adapts to regular exposure to a substance (e.g., caffeine or a prescription drug). When that substance is taken away, (even if originally prescribed by a doctor) symptoms can emerge while the body re-adjusts to the loss of the substance. Physical dependence can lead to craving the drug to relieve the withdrawal symptoms. Tolerance is the need to take higher doses of a drug to get the same effect. It often accompanies dependence, and it can be difficult to distinguish the two. Addiction is a chronic disorder characterized by drug seeking and use that is compulsive, despite negative consequences.

How do drugs work in the brain to produce pleasure?

Nearly all addictive drugs directly or indirectly target the brain’s reward system by flooding the circuit with dopamine. Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, cognition, motivation, and reinforcement of rewarding behaviors. When activated at normal levels, this system rewards our natural behaviors. Overstimulating the system with drugs, however, produces effects which strongly reinforce the behavior of drug use, teaching the person to repeat it.

Is drug use or misuse a voluntary behavior?

The initial decision to take drugs is generally voluntary. However, with continued use, a person’s ability to exert self-control can become seriously impaired. Brain imaging studies from people addicted to drugs show physical changes in areas of the brain that are critical for judgment, decision-making, learning, memory, and behavior control. Scientists believe that these changes alter the way the brain works and may help explain the compulsive and destructive behaviors of a person who becomes addicted.

Can addiction be treated successfully?

Yes. Addiction is a treatable, chronic disorder that can be managed successfully. Research shows that combining behavioral therapy with medications, if available, is the best way to ensure success for most patients. The combination of medications and behavioral interventions to treat a substance use disorder is known as medication-assisted treatment. Treatment approaches must be tailored to address each patient’s drug use patterns and drug-related medical, psychiatric, environmental, and social problems.