Opioids attach to receptors in the brain. Normally these opioids are the endogenous variety that are created naturally in the body. Once attached, they send signals to the brain of the "opioid effect" which blocks pain, slows breathing, and has a general calming and anti-depressing effect. The body cannot produce enough natural opioids to stop severe or chronic pain nor can it produce enough to cause an overdose.
opioids can activate receptors because their chemical structure mimics that of a natural neurotransmitter. This similarity in structure "fools" receptors and allows the drugs to lock onto and activate the nerve cells. Although these drugs mimic brain chemicals, they don't activate nerve cells in the same way as a natural neurotransmitter, and they lead to abnormal messages being transmitted through the network.
Opioids target the brain's reward system by flooding the circuit with dopamine. Dopamine is a neurotransmitter present in regions of the brain that regulate movement, emotion, cognition, motivation, and feelings of pleasure. The overstimulation of this system, which rewards our natural behaviors, produces the euphoric effects sought by people who misuse drugs and teaches them to repeat the behavior.
Our brains are wired to ensure that we will repeat life-sustaining activities by associating those activities with pleasure or reward. Whenever this reward circuit is activated, the brain notes that something important is happening that needs to be remembered, and teaches us to do it again and again, without thinking about it. Because drugs of abuse stimulate the same circuit, we learn to abuse drugs in the same way.
To suppress the debilitating symptoms of cravings and withdrawal, enabling the patient to engage in therapy, counseling and support, so they can implement positive long-term changes in their lives which develops into the new healthy patterns of behavior necessary to achieve sustained addiction remission. - explain -