Dopamine is the primary neurotransmitter involved in the rewarding effects of drugs of abuse. It is released in the brain's reward pathway, which is a network of brain regions that are involved in pleasure, motivation, and reinforcement.

Tolerance is the process by which the brain adapts to the presence of a drug of abuse. It occurs when the brain reduces its response to the drug, requiring higher doses to achieve the same effect.

The nucleus accumbens is a brain region that is primarily involved in the development of drug addiction. It is part of the brain's reward pathway and is involved in the processing of pleasure and reward.

Withdrawal is the term for the physical and psychological symptoms that occur when a person stops using a drug of abuse. These symptoms can range from mild to severe and can include anxiety, depression, insomnia, and cravings for the drug.

GABA is the primary neurotransmitter involved in the development of drug dependence. It is an inhibitory neurotransmitter that helps to regulate brain activity. When GABA levels are decreased, it can lead to an increase in anxiety and cravings for drugs of abuse.

Sensitization is the process by which the brain becomes more sensitive to the effects of a drug of abuse. It occurs when repeated exposure to the drug leads to an increase in the brain's response to the drug.

The prefrontal cortex is a brain region that is primarily involved in the control of impulsive behavior. It is responsible for planning, decision-making, and inhibiting inappropriate behavior.

Classical conditioning is the process by which a person learns to associate a drug of abuse with a particular environment or situation. This can lead to cravings for the drug when the person is exposed to the associated cues.

Serotonin is the primary neurotransmitter involved in the regulation of mood and emotion. It is also involved in sleep, appetite, and memory.

Operant conditioning is the process by which a person learns to associate a drug of abuse with a particular behavior. This can lead to the development of drug-seeking behavior, in which the person takes the drug in order to obtain a desired outcome.

The hippocampus is a brain region that is primarily involved in the processing of memories. It is responsible for the formation, consolidation, and retrieval of memories.

Dependence is the process by which a person's brain and body adapt to the presence of a drug of abuse. It is characterized by a physical and psychological need for the drug, and can lead to withdrawal symptoms when the drug is stopped.

GABA is the primary neurotransmitter involved in the regulation of sleep and wakefulness. It is an inhibitory neurotransmitter that helps to promote sleep.

Tolerance is the process by which a person's brain and body become less sensitive to the effects of a drug of abuse. It occurs when repeated exposure to the drug leads to a decrease in the brain's response to the drug.

The prefrontal cortex is a brain region that is primarily involved in the regulation of attention and focus. It is also involved in planning, decision-making, and working memory.