Substance abuse may be seen with opioids, cannabis, cocaine, hypnotics and sedatives. Cannabis is the drug most frequently abused (45 %). The prevalence of substance abuse in chronic non-malignant pain is between 5 and 25 %. Patients having addiction may show an intense desire for the drug. They may increase the dosage without clinical advice. They may continue medications even if the pain is not there. They may try to manipulate to obtain medications. This must be distinguished from “pseudo-addiction” whose patients seek additional medication due to inappropriate pain management.

The predictability of a person becoming an addict to opioids depends on genetic, environmental, social and cultural factors. Those that are from lower social class, are unemployed and have less education are more likely to be prone to addiction. Depression and anxiety also make a person more prone to addiction.