Depression and pain: the influence of substance abuse

Pain is a common problem for cancer patients, with approximately 70% of patients experiencing severe pain at some point in the course of their illness. Nearly 75% of advanced cancer patients in the USA have pain and, despite the availability of treatments, 25% of cancer patients still die in severe pain. Many factors can influence the pain experience for the cancer patient. One major factor is the presence of clinical depression. Studies have shown that approximately 25% of cancer patients will experience clinical depression during the course of their illness that will require treatment with antidepressants. Certainly, the presence of a clinical depression will negatively impact how patients experience their cancer pain, making them more vulnerable to stress. With the rapidly increasing incidence of substance abuse in the USA, one way that many people cope with their depression and other stressors is with the misuse and abuse of substances. The cancer patient is not immune to this form of self-medication or frank abuse. Understanding the role of depression and substance abuse in the expression and experience of pain is essential for the pain physician working with this complex patient population. Incorporation of screening questions, both verbal and written, to the comprehensive pain evaluation can increase the physician’s recognition of risk factors for depression and substance abuse, allowing for earlier referral to mental health practitioners who can actively participate in the multidisciplinary pain assessment and treatment.