What might be indicated by tolerance in substance use?

The correct response identifies that tolerance in substance use signifies a need for increased doses to achieve the same effect. Tolerance develops when an individual's body becomes accustomed to a substance over time, requiring them to consume higher quantities to attain the previously experienced effects. This phenomenon occurs because the body adapts to the presence of the substance, leading to changes in metabolism, receptor sensitivity, or neurotransmitter levels.

As tolerance increases, the person may find that the initial dose no longer provides the desired outcome, thereby prompting them to raise their dosage, which can be a concerning sign of escalating substance use or possible dependency. This aspect of tolerance is crucial to understand in recognizing impairments in the workplace since it may indicate the individual is consuming more of a substance in an attempt to gain the same effects, which can impair their cognitive and physical abilities.

Other options do not accurately reflect the definition of tolerance. For example, improved function suggests that the person is utilizing substances effectively, which contradicts the impact that tolerance generally has. Decreased drug use would imply a reduction in consumption, which is contrary to the concept of tolerance. Lastly, withdrawal symptoms typically emerge when a substance is reduced or discontinued, rather than describing the gradual adaptations leading to tolerance.