Final answer:
Addictive drugs increase dopamine levels in the brain, leading to euphoria and the drug's addictive properties. Cocaine, for example, inhibits dopamine reuptake in the nerve synapses. Continuous use can deplete neurotransmitters and lead to mood and cognitive disturbances.
Step-by-step explanation:
Addictive drugs rapidy increase levels of the neurotransmitter dopamine in the brain. This increase in dopamine occurs because many addictive substances act as stimulants, and their action prevents nerve cells from reabsorbing dopamine from the synapse. Cocaine, for instance, acts by inhibiting the reuptake of dopamine, leading to higher concentrations available to stimulate pleasure centers in the brain, which is responsible for the drug's 'high' and addictive quality.
The result of increased dopamine action is a feeling of euphoria or pleasure, often leading to the compulsive use of the substance despite the potential negative consequences. However, after intense stimulation of the reward system, dopamine levels can deplete rapidly, leaving a user feeling a lack of pleasure and with a strong craving for more of the drug. Prolonged use of stimulants like cocaine and amphetamines can ultimately lead to a depletion of dopamine and other neurotransmitters, resulting in mood disturbances and cognitive issues.
Understanding the role of dopamine in drug addiction is critical as it sheds light on the biochemical processes involved in the compulsive seeking and use of addictive drugs.