Fentanyl's rewarding properties, like other opioids, make its abuse more probable, both in its illegal and legal guises. Fentanyl binds to opioid receptors in the brain, located in the regions responsible for processing pleasure and mood.

Long-term fentanyl usage is associated with the development of tolerance, which results in the requirement for higher doses of the drug to produce the same effects.

Individuals who abuse fentanyl often report developing a tolerance to the drug, which results in them needing increasingly greater dosages to get the same effects. Fentanyl addiction may develop in certain users over time.

When someone develops a dependency on a substance, their body has adapted physiologically to having that substance present; as a result, they experience withdrawal symptoms if they try to reduce or stop using the drug.

Someone with a high degree of physiological dependency may drink excessively or use drugs compulsively to stave off the unpleasant effects of quitting.

Researchers have shown that fentanyl withdrawal is complicated by some variables that might lead to more severe symptoms and even more bouts of withdrawal. A few examples of them are:

• Quantity, frequency, and duration of fentanyl usage.

• The mode of delivery.

• Combination usage of fentanyl and other drugs is referred to as "polysubstance use."

• Root causes related to physical and psychological health.