There are more similarities than differences in brain structures and functioning as most people’s brains work in predictable ways. For example, the effect of recreational drugs on synaptic transmission e.g., heroin is an agonist so binds to opioid receptors to trick the brain into releasing endorphins which relieves pain/reduces stress and increase dopamine which improves mood and gives the user a feeling of ‘euphoria’. This mode of action is the same for everyone and therefore the damage caused to the brain of addicts is the same.
