Dopamine is a neurotransmitter. Neurotransmitters are released from neurons and travel in microscopic spaces (called “synapses”) to inter-connected neurons to send messages from one brain cell to another. To accomplish this, neurotransmitters “dock” with “receptors on the surface of message-receiving neurons, stimulating them via an electro-chemical exchange. Dopamine creates the feeling of pleasure by docking with neurons in the Reward System, stimulating those neurons and the Reward System as a whole.
Excessive drug use can cause permanent change to the Reward System neurons.This results from increasing drug tolerance, a process of accelerating change that makes the Reward System less efficient and requires users to take more drugs to obtain the same high they used to get from less drugs. Tolerance alters brain cells physically, changing their function. Eventually, as tolerance deepens, it alters the nature of the drug using experience, from liking drugs for their euphoric effects to needing them simply to feel normal and hold off withdrawal.
The brain must be balanced to operate properly and has a defensive systems to monitor and correct imbalances. If the brain encounters drug-induced over-stimulation occasionally, the brains defensive system respond to each as an individual event. However, if the Reward System is over-stimulated regularly over a long period of time, the brain learns to anticipate the over stimulation, prompting a much more powerful and long lasting – even permanent defensive reaction.
In other words, in the face of chronic over stimulation by drugs, the brain’s defensive systems cause physical and structural changes in the Reward Systems. Ultimately, adaptions that drug exposure elicits in individual neurons alter the functioning of those neurons, which in turn alters the functioning of neural circuits in which those neurons operate. This leads eventually to the complex behaviors that characterize an addictive state. Essentially, long term predictable drug abuse causes the brain to reprogram itself in defense. That’s what tolerance does.
However, since tolerance dulls the high that drugs evoke, users retaliate by taking more.They increase the amount of dopamine by increasing the dose and the frequency of drugs, or both, so they get the same reward they used to with less, before tolerance developed. The brain, in turn responds tries to counteract drug abuse by gumming up the reward system ever further while users compensate by taking more and more drugs. This prompts further brain change, which in turn elicits increasing drug taking, accelerating a continual downward spiral. That’s a key reason addiction is a progressively worsening disease. The changes caused by tolerance establish what scientist refer to as a “new normal” for the addictive brain – a less effective Reward System.
There are ways to reverse the effect drugs have on the brain, it’s called recovery, and just as addiction is progressive, recovery is a process, when practiced can lead to a new life, rebuilding and refreshing the Reward System.
More will be revealed in upcoming posts, allow me to guide you on the journey of recovery.