Researchers now know that intense memories, called conditioned responses, create physical changes in the brain. Some memories are very powerful and are easily brought back with certain triggers. Drug use is thought to be one of those memories that is, for addicts, very strong.
The feeling of euphoria is an intense memory for someone in recovery. That memory is stamped onto the brain. Driving by a corner where you used to buy your drugs or the sight of a hypodermic needle are both triggers. These triggers bring back memories of using, making staying in recovery difficult. They create a strong desire for someone in recovery to use.
The only way to try to change these memories is to find other coping mechanisms when you encounter these triggers. If you drive past a corner that triggers a memory, then you can avoid the craving associated with that memory by taking a different route. If a needle triggers a memory of use then try to go every year for a flu shot with your child or make sure you go for your child’s yearly shots so you can start to develop new associations. These triggers aren’t just psychological weaknesses. They are the result of physical changes in the brain caused by long-term opioid use.
This is part of the reason why addiction, and specifically opioid use disorder, is defined as a chronic brain disease. The physical changes in the brain as a result of long-term opioid use are as real as any physical symptom associated with other diseases, such as heart disease or diabetes.
Unlike withdrawal symptoms and physical cravings, no medication assisted treatment will wipe-out memories. People are prescribed Suboxone (or other buprenorphine based medications) by their doctor to help them with withdrawal and cravings, but only behavioral therapy can help manage the triggers associated with intense memories.
For anyone interested in a more technical explanation, below is a quote from The Neurobiology of Opioid Dependence: Implications for Treatment (Kosten & George, 2002):
One of the brain circuits that is activated by opioids is the mesolimbic (midbrain) reward system. This system generates signals in a part of the brain called the ventral tegmental area (VTA) that result in the release of the chemical dopamine (DA) in another part of the brain, the nucleus accumbens (NAc) (Figure). This release of DA into the NAc causes feelings of pleasure. Other areas of the brain create a lasting record or memory that associates these good feelings with the circumstances and environment in which they occur. These memories, called conditioned associations, often lead to the craving for drugs when the abuser reen-counters those persons, places, or things, and they drive abusers to seek out more drugs in spite of many obstacles.