What indicates physiological dependence on a substance?

Physiological dependence on a substance is characterized primarily by the presence of tolerance and withdrawal symptoms. Tolerance refers to the body's adaptation to the substance, resulting in the need for increased amounts of the substance to achieve the desired effect. Withdrawal symptoms occur when a person reduces or stops using the substance, leading to physical and psychological effects that can be uncomfortable or even severe.

The combination of these two factors—tolerance and withdrawal—signals that the body has become reliant on the substance to function normally. In contrast, increased craving for the substance, a reduction in negative emotional states, and increased social interaction may indicate psychological dependence or changes in behavior but do not necessarily signify physiological dependence. Therefore, the presence of tolerance and withdrawal is a definitive indicator of physiological dependence on a substance.