What is a common side effect of dependence on drugs?

Dependence on drugs leads to the body becoming accustomed to the presence of the substance. When the drug is not available, the body reacts negatively, often resulting in withdrawal symptoms. These symptoms can vary widely depending on the drug but may include physical symptoms like nausea, sweating, shaking, and psychological symptoms such as anxiety, irritability, and depression. This physiological reaction occurs because the body has adapted to the drug's effects, and its absence disrupts the normal functioning that has been modified by prolonged use of the substance.

In contrast, the other options do not accurately reflect the consequences of drug dependence. Increased physical energy, for instance, may only be a temporary effect of certain stimulants, while dependence typically leads to fatigue and lethargy. Improved mental clarity is also not associated with dependence; instead, many drugs can impair cognitive function. Lastly, dependence often leads to increased anxiety rather than a reduction because the absence of the substance can trigger anxiety or exacerbate existing issues. Thus, experiencing withdrawal symptoms when not using the drug is a clear manifestation of dependence.