Cannabis Use Moderates the Relationship between Pain and Negative Affect in Adults with Opioid Use Disorder
Marian Wilson, Hannah Y. Gogulski, Carrie Cuttler, Teresa L. Bigand, Oladunni Oluwoye,Celestina Barbosa-Leiker, MaryLee A. Roberts
Addictive Behaviors, 2017, 30 p.
doi : 10.1016/j.addbeh.2017.10.012
Introduction : Adults in Medication-Assisted Treatment (MAT) for opioid addiction are at risk for substance use relapse and opioid overdose. They often have high rates of cannabis use and comorbid symptoms of pain, depression, and anxiety. Low levels of self-efficacy (confidence that one can self-manage symptoms) are linked to higher symptom burdens and increased substance use. The effects of cannabis use on symptom management among adults with MAT are currently unclear. Therefore, the primary purpose of this study is to examine whether cannabis use moderates the relationships between pain and negative affect (i.e., depression and anxiety) and whether self-efficacy influences symptom interactions.
Methods : A total of 150 adults receiving MAT and attending one of two opioid treatment program clinics were administered a survey containing measures of pain, depression, anxiety, self-efficacy, and cannabis use.
Results : Cannabis use frequency moderated the relationships between pain and depression as well as pain and anxiety. Specifically, as cannabis use frequency increased, the positive relationships between pain and depression and pain and anxiety grew stronger. However, cannabis use was no longer a significant moderator after controlling for self-efficacy.
Conclusions : Results suggest that cannabis use strengthens, rather than weakens, the relationships between pain and depression and pain and anxiety. These effects appear to be driven by decreased self-efficacy in cannabis users. It is important to understand how self-efficacy can be improved through symptom self-management interventions and whether self-efficacy can improve distressing symptoms for people in MAT.
Keywords : Anxiety, Cannabis Use, Depression, Opioid Addiction, Pain, Self-Efficacy
The number of Americans with an opioid use disorder related to prescription pain relievers climbed from 1.4 million to 1.9 million in the last 10 years (Substance Abuse and Mental Health Services Administration [SAMHSA], 2015). Opioid overdose death rates have more than tripled in the past two decades and are now the second leading cause of accidental death in the United States (U.S.) (Centers for Disease Control and Prevention [CDC], 2017). Death certificate data indicate that states with legalized medical cannabis have 25% lower annual opioid-related deaths (Bachhuber, Saloner, Cunningham, & Barry, 2014). While the root cause of this relationship is unknown, it has been hypothesized that the ability to obtain cannabis easily may reduce opioid use (Bradford & Bradford, 2016; Miller, 2016) and that cannabis may be used as a substitute drug (Corroon, Mischley, & Sexton, 2017). Still, more robust research is needed to assess positive and negative effects of cannabis prior to endorsing its use as a harm reduction strategy to reduce opioid overdose deaths. Unmeasured factors could account for improvements in death rates, such as concomitant reductions in opioid prescribing and policy changes (Hall & Weier, 2015).
Widespread use of cannabis has been documented among adults in Medication Assisted Treatment (MAT) for opioid use disorders (Bawar, 2015). Individuals prone to opioid misuse often use substances, including cannabis, to “self-medicate” disturbing symptoms (Alford et al., 2016). While as many as 62% of adults in MAT present with co-existing chronic pain (Dunn, Brooner, & Clark, 2014), little is known about their cannabis use in relation to pain and management of other symptoms. Some studies indicate that adults in MAT experience cooccurring depression and anxiety at the respective rates of 19-22% and 44% (Batki, Canfield, & Ploutz-Snyder, 2011; Savant et al., 2013). Still lacking is sufficient empirical understanding of opioid-cannabis interactions related to symptom relief. More specifically, a dearth of knowledge exists about cannabis’ effects on pain and affective symptoms among adults receiving MAT. Because the relapse rates for people in MAT are high (up to 86%) (Termorshuizen et al. 2005; Tkacz, Severt, Cacciola, & Ruetsch, 2012), and the risk for overdose is three times greater posttreatment (Cornish, Macleod, Strang, Vickerman, & Hickman, 2010; Davoli et al., 2007), it is important to consider whether adjuncts, including cannabis, could assist in reducing distressing symptoms of pain and affect, opioid dosages, risk of overdose deaths, and/or relapses. Such information is essential to guide patients regarding risks and benefits of cannabis, particularly as clinicians strive to limit opioid dosages and follow recommendations to reduce overdose risk for people with pain and/or opioid use disorders (National Institute on Drug Abuse, 2015).
Medical cannabis patients primarily report using cannabis to manage three conditions: pain, anxiety, and depression (Sexton, Cuttler, Finnell, & Mischley, 2016). A consensus committee of the U.S. National Academy of Sciences, Engineering, and Medicine (2017) concluded that there is “substantial” evidence for cannabis use to relieve chronic pain symptoms. The strongest evidence they cite comes from a systematic review that includes 28 randomized controlled studies and concludes that moderate quality evidence exists supporting cannabinoids to improve chronic pain (Whiting et al., 2015). Yet, little substantial evidence exists on cannabis use and pain relief that is specific to MAT populations. Rodent models suggest that agonists targeting the cannabinoid 2 and mu opioid receptors act synergistically to reverse inflammatory, post-operative, and neuropathic pain while preventing opioid-induced reward behaviors (Grenald et al., 2017). In addition, findings from animal studies indicate that activating the endocannabinoid system may help minimize stress and depression (Haj-Dahmane & Shen, 2014). Despite frequent reports of cannabis use to alleviate negative affect, limited evidence supports its use for improving either depression or anxiety in human trials (National Academy of Sciences, Engineering, and Medicine, 2017). Intermittent cannabis use has been found to diminish opioid withdrawal symptoms for individuals in naloxone treatment (Raby et al., 2009), and medical cannabis patients report that they are able to decrease amounts of opioids they consume when they use cannabis for pain (Reiman, Welty, & Solomon, 2017). While these outcomes are encouraging, it is critical to ascertain if using cannabis to self-manage symptoms may lead to untoward effects, especially due to the insufficiency of research in this area.