Pain prospectively predicts alcohol use disorder among people living with HIV: A commentary on Palfai et al. (2024)

Abstract

Alcohol use and pain are common among People Living with HIV/AIDS (PLWH) and present a significant public health concern in this high-risk group. The Reciprocal Model of Pain and Substance Use posits that bidirectional interactions between pain and alcohol use maintain and exacerbate one another (Ditre et al., 2019). As research and clinical interest in pain–alcohol associations continue to grow, the field will be advanced by (a) prospective studies that are capable of identifying changes in pain and alcohol use over time, (b) research that focuses on high-risk populations who evince pain and alcohol-related health disparities, and (c) examination of pain–alcohol associations across a spectrum of pain and alcohol-related characteristics. Palfai et al. (2024) made a significant contribution to the literature in all of these domains through their examination of both pain intensity and interference as prospective predictors of heavy drinking and Alcohol Use Disorder (AUD) among a racially and ethnically diverse sample of PLWH. Leveraging data from an existing cohort study, they found that PLWH with moderate/severe pain (vs. no/mild pain) at baseline were more than twice as likely to meet DSM-5 criteria for AUD at 12-month follow-up. Moreover, those with moderate/severe pain-related interference (vs. no/mild interference) in daily functioning were more than 3 times more likely to meet criteria for AUD. In both instances, greater pain and interference were further associated with greater AUD severity. The study conducted by Palfai et al. (2024) provides a rich context for considering the current state-of-the-art and future directions in pain–alcohol research.

PLWH are an ideal population in which to study pain–alcohol associations because HIV is highly comorbid with both pain and alcohol use, and PLWH face disparities across numerous health outcomes. Indeed, prevalence rates of unhealthy alcohol use (i.e., a range that encompasses risky or potentially harmful drinking through AUD) are up to six times greater among PLWH than among the general population (e.g., Duko et al., 2019; SAMHSA, 2024). This is of particular concern given that PLWH experience disproportionate alcohol-related disease burdens because of the adverse effects on HIV-related outcomes (Molina et al., 2018). Like unhealthy alcohol use, chronic pain is more prevalent among PLWH, with rates about twice as high as the general population (Madden et al., 2020; Yong et al., 2022). This is reflected in baseline rates of pain and alcohol use in Palfai et al.'s (2024) sample, with nearly half of participants reporting moderate to severe pain intensity and interference and 53% reporting unhealthy alcohol use (i.e., either heavy drinking or AUD) at baseline.

Drawing from a larger literature on diverse pain conditions (e.g., musculoskeletal pain, arthritis), the Reciprocal Model of Pain and Substance Use posits that people who engage in unhealthy levels of alcohol use are at greater risk for developing chronic pain and poorer pain-related outcomes (Ditre et al., 2019). Conversely, pain is a potent motivator of drinking behavior, triggering both acute bouts of alcohol use/intoxication and predicting a progression to greater drinking severity over time. The effects of pain on alcohol use seem to be more pronounced as the spectrum of unhealthy use behavior increases from heavy or potentially hazardous drinking through AUD (e.g., Zale et al., 2015). Indeed, people seeking treatment for AUD reliably report using alcohol to cope with pain, escalating their alcohol use to control pain, and concern that pain will be a barrier to abstinence (Hall et al., 2023). The findings from Palfai et al. (2024) contribute to the rapidly growing literature that indicates pain–alcohol associations are relevant to people who live with a variety of painful conditions and further highlight the importance of understanding how maladaptive responses to pain (e.g., declines in daily functioning) might contribute to unhealthy drinking.

It is particularly notable that Palfai et al. (2024) found pain-related interference was more strongly associated with AUD than was pain intensity. Pain-related interference broadly refers to the extent to which pain negatively impacts daily activities and experiences (e.g., work, socialization, physical movement or activity, mood). Pain is a multidimensional construct that includes sensory, cognitive, motivational, and behavioral components. Pain-related interference has become a growing public health focus because of mounting evidence that it is not simply an analog transformation of pain intensity (Jordan et al., 2019). Pain-related interference can occur at any level of intensity, and more than half of people with chronic pain do not experience significant interference with their functioning (Dahlhamer et al., 2018). Palfai et al.'s (2024) findings suggest that PLWH whose functioning is most negatively impacted by pain are at the greatest risk for more severe AUD, but not heavy drinking. AUD is distinguished from heavy drinking, in part, when alcohol use causes impairments in functioning. Thus, it may be that pain serves as a marker of disparities in alcohol-related problems, regardless of consumption level. Future research is needed to better understand how interference from pain and alcohol use may compound or exacerbate one another. This work is particularly important to conduct among PLWH because they represent a group who disproportionately face social determinants of health, like unemployment and housing insecurity, that can significantly negatively impact functioning and outcomes of all three conditions (Aidala et al., 2016; Maulsby et al., 2020).

A related and important issue raised by Palfai et al. (2024) is that the HIV population is aging, with an average age of 50 years in their sample. This suggests a need to approach pain and alcohol research from a lifespan perspective, and future research will need to consider how age-related comorbidities may interact with pain–alcohol relations among PLWH. The prevalence rates of both HIV and substance use disorders are increasing in older adults, and biopsychosocial effects of aging place older adults at greater risk for substance-related harm and poorer HIV- and other health outcomes (Jones et al., 2023; Molina et al., 2018). The transition to late adulthood can also include psychosocial challenges in navigating potential physical and cognitive decline and role changes across multiple domains (e.g., retirement, family relationships, recreational opportunities). Thus, future research is needed to better understand how development in later adulthood can impact and be impacted by co-occurring pain and alcohol use. For example, pain-related interference with occupational functioning may be less important in a retired population, while older adults who face fewer social and recreational opportunities may be disproportionately impacted by any interruptions to their engagement. A prior review highlighted the potential role of alcohol's social facilitation effects in the context of diminishing social opportunities due to pain (Zale et al., 2015), and future research is needed to identify how and to what extent pain motivates alcohol use and escalation in aging populations due to developmental changes like declines in socialization.

The cohort study, from which these data were drawn, recruited participants with a recent history of illicit substance use, potentially hazardous alcohol use or nonprescribed medication use, or a lifetime history of substance use disorder (SUD) or injection drug use. Although data are not available to fully quantify all potential polysubstance use in the sample, Palfai et al. (2024) report that 64% of their participants endorsed past 30-day illicit substance use (i.e., not a prescribed medication) at baseline. The prevalence of chronic pain increases with a greater number of comorbid SUD diagnoses (John & Wu, 2020), and people with AUD who experience pain are more likely to report alcohol overdoses that occurred while using other substances (Fernandez et al., 2019). As such, the field is increasingly interested in identifying the effects of pain on the co-use of multiple substances. For example, co-use of alcohol and prescription opioids can have fatal consequences, and a recent review suggested that alcohol/opioid co-use could reflect maladaptive attempts to regulate negative affect or pursue analgesic effects beyond that which can be obtained from either substance alone (Zale et al., 2021). Indeed, greater pain intensity and interference are associated with the intention to co-use alcohol and opioids, which has a large association with simultaneous use that results in overlapping effects from both substances (Powers, Lape, et al., 2023). An interesting direction for future empirical inquiry would be to examine pain as a prospective predictor of co-use of alcohol and other substances among PLWH. Mechanistic studies capable of identifying modifiable factors that motivate co-use further have the potential to inform novel interventions. For example, experimental studies could test the effects of expectancies for analgesia (e.g., via an expectancy challenge) on craving and demand for co-use of alcohol and other substances. Ecological momentary assessment (EMA) could also be used to examine real-time associations between constructs identified as transdiagnostic vulnerabilities to pain and substance use (e.g., anxiety sensitivity, pain catastrophizing; Ferguson et al., 2020; Zale et al., 2021), pain intensity, and co-use of alcohol and other substances. The frequent assessment paradigm employed in EMA would be particularly suited to examining simultaneous use that results in overlapping effects of both substances within a short timeframe.

Palfai et al.'s (2024) findings that pain is a prospective predictor of AUD severity are consistent with a clinical literature that identifies pain as a unique barrier to alcohol treatment, and some of this formative work is being conducted among PLWH. For example, women living with HIV who were treated with naltrexone showed significantly slower declines in their alcohol use if they reported using alcohol to manage their pain, relative to those who did not use alcohol for pain management (Parisi et al., 2023). Qualitative work conducted by the lead author further indicates that although PLWH can identify using alcohol for pain coping, they may not readily identify the value or rationale of pain management interventions in the context of alcohol use (Palfai et al., 2019). Future clinical research can seek to further identify modifiable factors that impart vulnerability to both pain and alcohol use (e.g., maladaptive cognitive-affective and behavioral responses to aversive internal states; sleep disturbances; Zale et al., 2021), address motivation to use alcohol in the context of pain, provide education to patients about the potential harms of alcohol use in the context of pain and HIV, and assist patients in developing effective pain self-management strategies that enable coping without alcohol.

The authors identify important limitations to their work that also deserve further consideration. First, their heavy drinking variable was a dichotomous composite of two drinking indices measured over different time periods. Participants were considered to have engaged in heavy drinking if they exceeded a cutoff for total weekly consumption in the 2 weeks prior to the interview or if they engaged in at least one heavy drinking episode over the past month. It is possible that a more nuanced approach could elucidate associations between pain and heavy drinking that were not evident in the published analyses. For example, it would be interesting to know whether pain predicted differences in patterns of unhealthy alcohol use (e.g., elevated weekly consumption without engaging in heavy episodic drinking vs. episodes of heavy episode drinking punctuated by periods of abstinence), overall frequency/quantity of use, or other markers of risk such as peak BAC. Qualitative data indicate that some PLWH might overestimate the safety of heavy episodic drinking when they do not drink alcohol on most days of the week (Palfai et al., 2019), and differences in patterns of use could inform the development of novel treatment components.

Second, the time period of pain assessment was in the past week prior to baseline. Thus, these data cannot tell us about how additional variations in temporal aspects of pain, like chronicity or recurrence, are associated with unhealthy drinking in PLWH. However, the past week pain variable is commonly used in pain-substance use research and has shown utility for detecting the effects of pain on substance use across a range of substances and populations cross-sectionally and prospectively (e.g., Powers, Maisto, et al., 2023; Zale et al., 2015). A transdiagnostic approach considers that people may have characteristic ways of responding to pain (e.g., with escape/avoidance behaviors) that serve as mechanisms driving pain–substance use relations (e.g., Zale et al., 2021). In this context, past week pain appears to be a useful analogue for pain responding more generally. This notion is supported by the findings that pain interference (capturing behavioral and affective responses to pain) was more strongly related to AUD than pain intensity (capturing a momentary appraisal of the sensory pain experience).

In summary, PLWH face disproportionate burdens from pain and AUD, as well as unique social determinants of health that may negatively impact the progression of all three conditions. Longitudinal associations, like those provided by this study, further strengthen our understanding that pain predicts worsening of alcohol-related problems over time and that PLWH may require novel integrated interventions that are designed to address their unique needs. Future research and treatment development efforts should consider the context of social determinants of health, use a lifespan approach, and examine how variations in the pain experience predicts patterns of drinking over time. Finally, research is needed to better understand the complex interplay of reciprocal effects between pain and alcohol use (e.g., how does subsequent AUD severity predicted by baseline pain then, itself, predict changes in pain thereafter, and how do those reciprocal effects impact treatment for both conditions?) among PLWH. Findings from Palfai et al. (2024) and other work conducted among PLWH can further inform our understanding of pain–substance use associations across a spectrum of painful conditions and populations with unique needs or health disparities (e.g., multiple comorbidities, cancer-related pain).

None declared.