When scientists first began studying addiction in the 1930s, it was widely accepted that people who were addicted to drugs or alcohol were morally flawed and simply lacked willpower. This led to a widespread view in society that addiction was a moral failing, rather than the brain disease it’s known to be today.

Incredible discoveries through scientific research have led to a much better understanding of addiction. As it turns out, addiction is the result of real and tangible changes in brain function that affect thought and behavior, and it’s regarded by the medical community as a disease that can be systematically diagnosed and successfully treated.

Unfortunately, few people among the general population understand why and how addiction develops and how treatment works to end an addiction for the long-term. The stigma of addiction as a moral failing persists in many circles, making things more difficult for people who are addicted to drugs or alcohol.

In this eBook, we aim to help you understand the complex ways in which drug and alcohol abuse affect brain function and how these changes may lead to a compulsion to use drugs. Once you understand how addiction’s compulsive behaviors develop, it’s easier to see how treatment can help an individual successfully end even the most severe, long-term drug or alcohol addiction.

Neuroscience 101: Neurons and Neurotransmitters

Your brain is a highly complex network of about one hundred billion neurons. Neurons are nerve cells that transmit information throughout the body by sending chemical and electrical messages back and forth thousands of times a minute, controlling everything we think, feel and do.

At the receiving end of a neuron, branched structures known as dendrites receive an electrical signal that is transported into the cell body, where it’s processed. From the cell body, the signal travels into a long, slim nerve fiber known as the axon. The neuron terminates at the end of the axon.

Between neurons is a gap known as a synapse. When one neuron needs to relay an electrical message to an adjoining neuron, it manufactures chemical messengers known as neurotransmitters. The neuron stores these chemicals in little packets called vesicles. The electrical signal causes the vesicles to open up and release the neurotransmitters into the synapse.

The neurotransmitters travel across the synapse and, like a key in a lock, link up to specialized receptors on the receiving neuron. Once the message has been received by the receiving neuron, the neurotransmitter molecules disconnect from the receptors and move back into the synapse, where they re-enter the sending neuron through a special structure called a transporter. Once back in the sending neuron, the neurotransmitters become available again to send future messages. The process of neurotransmitters moving back into the sending neuron is known as “reuptake.”

Scientists have identified dozens of neurotransmitters, and each individual neuron manufactures one or more of them. Each type of neurotransmitter produces particular effects, depending on what area of the brain it acts on.

Neurotransmitters Affected by Drugs

A number of neurotransmitters are affected by…

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