Which sign of drug abuse may involve mood swings or irritability?

Sudden mood changes or angry outbursts are a well-documented sign of drug abuse, primarily because many substances affect the brain's chemistry and emotional regulation. When an individual uses drugs, they may experience significant fluctuations in their mood due to the impact of the substance on neurotransmitters like serotonin and dopamine, which are directly associated with emotional well-being. These abrupt emotional shifts can manifest as irritability, aggression, or extreme emotional responses that deviate from the individual's baseline behavior.

Understanding that drug abuse can alter a person's emotional state is essential for recognizing the signs and potentially providing support or seeking intervention. This is particularly relevant in supervising special populations, where it's crucial to maintain awareness of behavioral changes that could indicate substance use issues. The other options reflect stable emotional states, which are typically not associated with drug abuse.