Which drug is primarily associated with dependence characterized by needing increasing amounts to achieve the same calming effect?

The drug primarily associated with dependence characterized by needing increasing amounts to achieve the same calming effect is benzodiazepines. This phenomenon, known as tolerance, often occurs with substances that affect the central nervous system, particularly those that have sedative or calming properties like benzodiazepines.

Benzodiazepines work by enhancing the effect of the neurotransmitter gamma-aminobutyric acid (GABA), which results in decreased neuronal excitability and a calming effect. Over time, with repeated use, the body may adapt to the presence of the drug, leading individuals to require higher doses to achieve the same anxiety-reducing or sedative effects. This progressive need for larger doses is a hallmark of physical dependence on these medications.

While other substances listed can also lead to dependence, they do not primarily exhibit tolerance in the same way benzodiazepines do. For example, cocaine typically leads to a short-lived high that can result in increased use, but the mechanism of dependence is markedly different from that of benzodiazepines. Alcohol and opioids can also lead to tolerance and dependence, but the question specifically highlights the calming effect, which aligns more closely with benzodiazepines.