Regardless of how it is consumed, alcohol and other drugs eventually make their way into the brain via the bloodstream. Once there, they affect how messages are sent through the brain.The brain is a massive communication centre passing messages back and forth to regulate what we think, feel and do. The messages are sent by chemicals in the brain called neurotransmitters.Drugs work in various ways. They eitherincrease or decreasethe production of neurotransmitters like dopamine (pleasure), noradrenaline (fight or flight) and serotonin (mood); or affect how much neurotransmitter stays active and for how long; or bind to natural receptors to mimic and artificially activate natural neurotransmitter pathways.

Reinforcement

Every drug affects different neurotransmitter pathways in different ways. Some affect more than one neurotransmitter. But most drugs impact the dopamine system in some way.Dopamine regulates emotion, motivation and feelings of pleasure. It’s the brain’s reward system. Our brains are hard-wired to ensure we repeat activities that are pleasant. When we do something enjoyable we get a little burst of dopamine, which signals to the brain we should do it again.Drugs release much larger amounts ofdopaminethan other dopamine-activating activities, like eating and sex, so they are more rewarding. As a result, there is a strong internal drive to repeat drug taking. The brain becomes primed to repeat drug taking over and over without really thinking about it.