Physiological dependence on a drug is primarily determined by which of the following factors?

Physiological dependence on a drug is primarily indicated by the presence of tolerance or symptoms of withdrawal. When an individual becomes physiologically dependent, their body adapts to the drug's presence by requiring increasing amounts to achieve the same effect—this is known as tolerance. Additionally, if the drug use is reduced or halted, the individual may experience withdrawal symptoms, which can range from mild discomfort to severe physical reactions depending on the substance. These symptoms arise because the body's normal functioning has been altered by the drug, and it is now struggling to regain its balance in the absence of that substance. Thus, the combination of tolerance and withdrawal symptoms is a clear marker of physiological dependence.

While the addictive properties of the drug, behavioral patterns of use, and psychological desire to use certainly play roles in an individual's relationship with substances, they do not specifically define physiological dependence, which is distinctly characterized by these physiological adaptations to the drug.