Chronic pain is a widespread issue, affecting an estimated 35-51% of adults in the UK. Despite its prevalence, many people struggle to find effective relief. This often leads to self-medication with substances like opioids and cannabis.
The Overlap: Pain, Opioids, and Cannabis
Research shows a strong connection between chronic pain and substance use disorders (SUDs). SUDs involve compulsive drug use, loss of control, and withdrawal symptoms. In chronic pain sufferers, negative reinforcement plays a role – the drugs reduce pain and negative emotions, providing temporary relief.
While chronic pain and SUDs often coexist, the true extent of this problem is still unclear.
The authors of a recent study assessed the current evidence that shows how people with chronic pain are more likely to develop SUDs.
Chronic Pain and Substance Use Disorder (SUD)
SUDs are characterised by compulsive drug-seeking behaviour, loss of control, and withdrawal symptoms. For chronic pain sufferers, the allure of illicit substances lies in their ability to temporarily alleviate pain and associated negative emotions, providing a much-needed respite from their suffering. This cycle of negative reinforcement without proper clinical oversight can easily lead to dependence and addiction.
However, the exact nature of this relationship remains a subject of ongoing investigation. While chronic pain is undoubtedly a risk factor for SUDs, the causal mechanisms are not fully understood. Researchers are actively exploring the genetic, environmental, and psychological factors that may contribute to this complex interplay.
Chronic Pain and Opioid Use Disorder (OUD)
Opioids, powerful painkillers, have long been used in chronic pain management. However, their efficacy in treating long-term pain is controversial, and their potential for abuse and addiction is well-documented. A significant proportion of patients prescribed opioids for non-cancer chronic pain end up misusing them or developing OUD. This alarming trend has led to a reevaluation of opioid prescribing practices and a growing emphasis on alternative pain management strategies.
Chronic Pain and Cannabis Use Disorder (CUD)
Chronic pain is the most common reason for medical cannabis use with a reported 65% of US patients citing it as their top reason for use. Whilst medical cannabis can be prescribed for chronic pain, there is a potential risk for the development of dependency and addiction. This can be minimised by ensuring that medical cannabis is only prescribed at the appropriate doses for eligible patients with the correct clinical oversight. For people who use illicit cannabis, there are no safeguards to monitor and limit this potential risk.
A meta-analysis found that 22% of people who used cannabis in the past year met the criteria for a CUD, raising questions about the long-term consequences of its use, particularly in individuals who self-medicate with illicit cannabis.
Exploring the Brain-Pain-Addiction Connection
Recent research has delved into the neurobiological mechanisms underlying the link between chronic pain and SUDs. One key finding is the involvement of the brain’s dopamine system, a critical player in reward and motivation. Both chronic pain and substance misuse can lead to long-term changes in dopamine signalling, potentially exacerbating negative emotions and contributing to the cycle of addiction.
Additionally, brain imaging studies have revealed structural and functional alterations in specific brain regions associated with pain processing and reward pathways in both chronic pain patients and individuals with SUDs. These findings suggest that chronic pain may sensitise the brain to the rewarding effects of drugs, increasing the risk of developing an addiction.
Emerging Therapies and Future Directions
As our understanding of the chronic pain-SUD connection deepens, researchers are exploring novel therapeutic approaches. Kappa opioid receptor (KOR) antagonists, a class of drugs that modulate dopamine release, have shown promise in preclinical studies for treating both chronic pain and SUDs. Additionally, neuroimmune modulators, which target the inflammatory processes in the brain, are being investigated for their potential to reduce cravings and withdrawal symptoms.
Furthermore, there is growing interest in non-pharmacological interventions, such as cognitive-behavioural therapy and mindfulness-based stress reduction, which have shown efficacy in managing chronic pain and reducing the risk of substance misuse.
The intertwined nature of chronic pain and SUDs presents a significant challenge for healthcare providers and researchers alike.
Addressing this complex issue requires a multi-faceted approach that encompasses early identification of at-risk individuals, personalised pain management plans, and comprehensive addiction treatment programs. By unravelling the intricate connections between chronic pain, substance misuse, and the brain, we can pave the way for more effective and compassionate care for this vulnerable population.
