Which of the following effects can methamphetamine and cocaine share?

Methamphetamine and cocaine are both powerful stimulant drugs that affect the central nervous system by targeting the dopamine pathways in the brain. The correct choice highlights their ability to inhibit dopamine reuptake, which is a significant mechanism by which both substances exert their stimulating effects.

When these drugs are consumed, they increase the levels of dopamine— a neurotransmitter associated with pleasure, reward, and motivation— by preventing its reabsorption (reuptake) into the neurons that released it. This leads to an accumulation of dopamine in the synaptic cleft, enhancing its effects and contributing to feelings of euphoria and increased energy. This increase in dopamine is a shared characteristic that plays a crucial role in the addictive potential of both substances.

The other effects listed, while associated with these drugs, are not shared characteristics in the same physiological sense. Enhancing mood stability is not a known effect of either drug, as both can lead to mood swings and emotional instability. Cognitive impairment can occur with frequent use or at high doses, but it is more a result of long-term effects rather than something that they share in a manner analogous to dopamine reuptake inhibition. Additionally, while both methamphetamine and cocaine can lead to insomnia, especially with heavy use, it isn't a direct pharmac