How Do Opioids Affect the Brain?

Opioids act on opioid receptors in the brain and spine. They essentially hijack the brain’s reward systems, which results in a cascade of other health effects. 

Opioids have both short and long term effects. Short term, opioids suppress pain and cause a euphoric rush. Long term, they can actually lead to a number of health concerns including increased pain over time (called opioid induced hyperalgesia). Learn more below. 

Types of Opioids

Opioids can be classified in a few different ways. 

Long-Acting vs. Short-Acting Opioids

One of the more helpful ways to categorize opioids is as either long-acting opioids or short-acting opioids.[1] Long-acting opioids spend a longer time affecting the body and generally have a less powerful overall effect compared to short-acting opioids. One of the most common long-acting opioids is methadone.

Short-acting opioids tend to have effects that last for a shorter period, and they are more potent. Common examples are heroin and fentanyl. While both short- and long-acting opioids can be addictive and can cause overdose, short-acting opioids will generally have a higher risk of both addiction and overdose risk. 

Natural, Semi-Synthetic & Synthetic Opioids

Opioids can also be categorized by how they were produced, with an opioid falling into one of three groups:

• Natural opioid (“opiate”)
• Semi-synthetic opioid
• Synthetic opioid

Natural opioids (previously referred to as opiates) are opioids that come from poppy plants. Heroin is the most widespread opioid of this type. 

Synthetic opioids are drugs that are synthesized in a lab. They chemically act upon opioid receptors in the brain despite not generally coming directly from poppy plant materials. 

Semi-synthetic opioids sit in the middle of these two groups. They come from poppy plant materials in part but are also processed in a lab to change their properties. 

While this is one way to classify opioids, it can lead to some misconceptions: Just because an opioid is “natural” from the poppy plant does not mean it is “safer”. For example, heroin is a “natural” opioid and yet it is much more potent than oxycodone, which is a synthetic opioid. 

How Opioids Affect the Brain & Body

Opioids work by activating opioid receptors in the brain and spinal cord.[2] This then causes the release of various neurotransmitters, the most well understood of which is dopamine. Dopamine then goes on to cause various changes in the body both short and long term. 

Short-Term Effects

In the short term, dopamine will suppress a person’s pain and cause them to feel a euphoric rush. It will also tend to sedate an individual, making them feel more relaxed. Common side effects from short term opioid use include dizziness, nausea, vomiting, constipation, and respiratory depression.[3] With heavy use or if combined with other drugs that can cause respiratory depression, a person can experience an overdose, which can be life threatening. 

Long-Term Effects

In the long term, opioid use can cause physical dependence, meaning a person will experience withdrawal symptoms if they quit using the drugs abruptly. One can also develop a tolerance for opioids over time, needing more opioids to achieve the same effect that a lesser amount of opioids once caused. Lastly, there is the phenomenon of “opioid induced hyperalgesia”, where one is so used to pain signals being blocked by opioids that stimuli that would normally not cause pain all of a sudden do, causing increased full body pain and a worsening of chronic pain overtime. For this reason, most societal guidelines recommend strongly AGAINST the use of long term use of opioids for chronic pain.

In addition, long term use of opioids has a number of physical health risks. A 2021 study found long-term opioid use can lead to a higher risk of cardiovascular complications, sleep-disordered breathing, infections, fractures, bowel dysfunction, overdose, and death.[4] This is true whether or not an individual is misusing opioids or if they are taking them as prescribed for a medical pain condition. The risk is real even for patients taking opioids as prescribed. 

Are the Changes Opioids Cause Reversible?

It depends. Many of the cellular level changes produced by long term use of opioids can be reversed, but it takes time (weeks to months or even years). For example, opioid induced constipation will certainly abate after stopping opioid use. 

However, if any organ damage occurs as the result of drug use, it may not fully heal even with abstinence. In addition, cognitive damage from chronic opioid use or ischemia after an overdose can lead to permanent, non-reversible damage. Moreover, the brain changes that leave an individual susceptible to psychological cravings persist life long in some individuals. 

Chronic vs. Untreatable

Addiction is a chronic condition, but it isn’t untreatable. [5] With appropriate treatment, a person with OUD can gain control over their drug use and lessen the degree to which they feel compelled to use opioids. They may even be able to achieve lifelong abstinence. 

Getting Help for Opioid Use Disorder

If you struggle with opioid use disorder (OUD), speak with an addiction professional. They can help get you an official diagnosis for your condition and answer any questions you may have about addiction. Then, they can work with you to put together a treatment plan to help you start the recovery process. 

OUD is usually best treated with a combination of talk therapy like cognitive behavioral therapy (CBT) and medication.[6] CBT is a form of therapy where you work with a professional to better understand how you think about drugs and the behaviors you engage in to help prevent you from repeating those behaviors in the future. 

While therapy is the first backbone of addiction treatment, medication is the second. 

Medications like methadone and Suboxone (buprenorphine/naloxone) can help to control drug cravings and eliminate withdrawal. MAT is highly evidence-based and supported by a large variety of government and medical organizations.[7]

MAT has been shown to improve treatment retention rates and long-term outcomes in patients with OUD.[8] These medications can save lives. These medications can be used for a few months during acute withdrawal or for years or even life long in patients who wish to prevent relapse. If you have questions about MAT for addiction recovery, reach out to Bicycle health today to learn more.