Which of the following is a behavioral indicator of substance use disorder?

Increased tolerance to the substance represents a key behavioral indicator of substance use disorder. Tolerance occurs when a person needs to consume larger amounts of a substance to achieve the same effects they once felt with smaller amounts. This is a physiological response that can indicate that the person's body has adapted to the substance, and it often signifies that the individual may be developing a dependency on it. Tolerance is a well-established criterion in diagnosing substance use disorders, as it reflects changes in behavior and body chemistry that are linked to the increased consumption of the substance.

Other options do not represent definitive indicators of a substance use disorder. Taking substances only during social events, for example, could indicate a social or situational use rather than a disorder. Exercising regularly to compensate for drug use may suggest an attempt to manage health but does not directly indicate a dependency or disorder. Having occasional cravings for substances may occur without constituting a disorder, as cravings can be normal even for non-dependent individuals in certain contexts.