Stop taking a drug and the body protests. That is dependence, a physiological adaptation that occurs when the body adjusts to the presence of a substance. It is not the same as addiction, though the two often travel together. You can be dependent on a drug without being addicted to it, and you can be addicted without being physically dependent.

The distinction matters. Beta blockers, antidepressants, and corticosteroids can all produce dependence. Stopping them abruptly causes withdrawal symptoms, sometimes dangerous. But nobody craves a beta blocker or steals to get one. Addiction involves compulsive use and continued use despite harm. Dependence is about the body's adaptation. A patient on long-term opioids for chronic pain may be physically dependent but not addicted. A person using cocaine may be addicted but not physically dependent in the classic sense.

What characterizes dependence:

• Tolerance. The same dose produces a smaller effect over time.
• Withdrawal. Symptoms appear when the drug is stopped or reduced.
• Physical adaptation. The body has changed to compensate for the drug's presence.
• Not a moral failing. It is a physiological response to repeated exposure.

Managing dependence means tapering gradually and treating withdrawal symptoms. Abrupt cessation can be dangerous for some drugs, including benzodiazepines and alcohol.