Impairment of which hormone/neurotransmitter is linked to higher drug dependency?

• A. Dopamine
• B. Serotonin
• C. Norepinephrine
• D. GABA

Answer: (A)

Dopamine is the neurotransmitter most closely tied to reward and reinforcement in the brain. When the dopaminergic reward system functions normally, it helps us learn which actions are rewarding and should be repeated. Drugs of abuse hijack this system by flooding it with dopamine, especially in the mesolimbic pathway (from the ventral tegmental area to the nucleus accumbens). Over time, repeated drug exposure can alter dopamine signaling—through changes in receptor density and transporter function—leading to tolerance and withdrawal. This dysregulation makes the brain seek more of the drug to achieve the same level of reward, increasing the risk of dependence.

While serotonin, norepinephrine, and GABA play important roles in mood, arousal, impulse control, and inhibition, the strongest link to the development and maintenance of drug dependency is with dopamine's reward signaling.