Almost one-fourth of opioids prescribed for chronic pain are misused, a new study concludes. A review of studies found average rates of misuse were 21 to 29 percent. Average rates of opioid painkiller addiction were 8 to 12 percent.

Researchers reviewed 38 studies of opioid misuse, abuse or addiction, HealthDay reports. Misuse was defined as using opioids in a way other than prescribed by a doctor, regardless of whether there were harmful effects. Abuse was defined as intentional use of the opioid for a nonmedical purpose, such as getting high or altering one’s state of consciousness. Addiction was defined as continued opioid use with actual or potential harmful effects, along with craving.

Lead author Kevin Vowles of the University of New Mexico and colleagues wrote in the journal Pain that the findings raise questions about the benefits of widespread opioid use for chronic pain, given the harmful consequences.

They wrote, “If it is accurate that approximately one in four patients on opioids display patterns of opioid misuse, but not addiction, then perhaps more efficient targeting of treatment resources would be of benefit.” For example, they note in a journal news release, “Even low-intensity interventions, such as patient education and monitoring, might be a viable alternative to simply not prescribing the medications for those at risk of misuse.”