Scoring systems have been derived to assess the likelihood of opiate addiction in chronic pain patients. Prescription opioids are the source of nearly half of misused opioids and the majority of these are initiated for trauma or surgery pain management. Further to this, healthcare practitioners have long been aware that despite the effective use of opioids for managing pain, the empirical evidence that supports the use of opioids long term is minimal. In addition to this, many studies that involved patients with chronic pain have failed to show any sustained improvement in their pain or ability to function with long term opioid use.According to position papers on the treatment of opioid dependence published by the United Nations Office on Drugs and Crime and the World Health Organization, care providers should not treat opioid use disorder as the result of a weak moral character or will but as a medical condition. Some evidence suggests the possibility that opioid use disorders occur due to genetic or other chemical mechanisms which may be difficult to identify or change, such as dysregulation of brain circuitry involving reward and volition. However, the exact mechanisms involved are unclear, leading to debate regarding the influence of biology and free will. Mechanism
Addiction
Addiction is a brain disorder characterized by compulsive drug use despite adverse consequences.
Signs and symptoms
Signs and symptoms include:
Drug seeking behavior
Increased use over time
Legal or social ramifications secondary to drug use
Multiple prescriptions from different providers
Multiple medical complications from drug use (HIV/AIDS, hospitalizations, abscesses)
Opioid cravings
Withdrawal symptomsAddiction and dependence are components of a substance use disorder and addiction represents the more severe form. Opioid dependence can occur as physical dependence, psychological dependence, or both. Withdrawal
Opioid withdrawal can occur with a sudden decrease in, or the cessation of, opioids after prolonged use. Onset of withdrawal depends on which opioid was used last. With heroin this typically occurs five hours after use, while with methadone it might not occur until two days later. The length of time that major symptoms occur also depends on the opioid used. For heroin withdrawal, symptoms are typically greatest at two to four days, and can last for up to two weeks. Less significant symptoms may remain for an even longer period, in which case the withdrawal is known as post-acute-withdrawal syndrome. Treatment of withdrawal may include methadone and buprenorphine. Medications for nausea or diarrhea may also be used. Opioid intoxication
Signs and symptoms of opioid intoxication include:

Opioid overdose
Signs and symptoms of opioid overdose include, but are not limited to:
Pin-point pupils may occur. Patient presenting with dilated pupils may still be experiencing an opioid overdose. Decreased heart rate
Decreased body temperature
Decreased breathing
Altered level of consciousness. People may be unresponsive or unconscious. Pulmonary edema (fluid accumulation in the lungs)
Shock
Death

Cause
Opioid use disorder can develop as a result of self-medication.