When most people think of medication for severe pain they think of morphine, the prototypical opioid used in the West today. Opioids have long been the mainstay for the management of chronic pain. Much has been written on their benefits and negative effects. Their popularity has waxed and waned over the years. It is currently waning.
The use of opioids can cause changes in the structure and function of the brain. These changes appear to correlate with declining effectiveness of the drugs and can appear within as little as one month of daily use.
Opioids cause changes in the anatomy, physiology, and function of the brain when taken daily. We can see brain changes on fMRI, and we can correlate these morphological changes with observed behavioral and functional changes in people who take opioids.
Opioid drugs start out as very effective. The typical patient with pain responds to a few hydrocodone tablets per day in the early phases of treatment, but soon finds that the medication becomes less effective which results in taking more frequent and higher doses to achieve the same result.
The net result is that opioids don’t work well over the long term.