What does physical dependence signify?

Physical dependence signifies a state in which the body has adapted to a substance, resulting in withdrawal symptoms when the substance is not available. This occurs because the body has become accustomed to the presence of the drug, altering its normal physiological functions. When the substance is suddenly removed or significantly reduced, the body may react negatively, leading to a range of withdrawal symptoms that can vary in severity. This phenomenon is a key indicator of physical dependence and highlights the body's reliance on the substance for normal functioning.

Other aspects such as unresponsiveness to drugs, resistance to treatment, and increased tolerance levels, while related to substance use, do not specifically define physical dependence. Unresponsiveness refers to a reduced reaction to the drug rather than dependence on it; resistance to treatment indicates challenges in addressing substance use without pertaining to the body's physiological adaptations; and increased tolerance levels involve needing more of the substance to achieve the same effect, which is a related but distinct concept. All these factors contribute to the complex nature of substance use disorders but do not encapsulate the essence of physical dependence as withdrawal symptoms do.