Psychological vulnerability and opioid medication use disorder risk in chronic pain: the mediating role of affective states and gender differences

Introduction Chronic pain is a leading cause of disability and a major public health concern, frequently accompanied by anxiety and depressive symptoms that may increase vulnerability to opioid medication misuse (OMUD). While affective mechanisms linking pain intensity to the risk of suffering an opioid use disorder have been documented primarily in Anglo-Saxon populations, evidence from Southern European healthcare contexts remains limited. Replicating these pathways across healthcare systems is essential to inform prevention-oriented pain management strategies. This study examined whether negative affective states mediate the relationship between subjective pain intensity and opioid medication use disorder risk in a Spanish clinical sample and whether these associations differ by gender. Methods Ninety-seven patients attending a specialized pain unit in Spain completed validated measures of pain intensity (visual analog scale, VAS), anxiety (Beck Anxiety Inventory, BAI), depression (Beck Depression Inventory II fast screen, BDI-FS), anhedonia (Snaith–Hamilton Pleasure Scale, SHAPS), and OMUD risk (current opioid misuse measure, COMM). Correlational, mediation (Sobel test), gender-stratified, and cluster analyses were conducted. Results Pain intensity was positively associated with anxiety, depression, and OMUD risk. Anxiety and depression significantly mediated the association between pain and OMUD risk, with effects observed in women but not in men. The cluster analysis identified a subgroup characterized by elevated negative affect that showed significantly higher pain intensity and markedly greater OMUD risk. Discussion These findings replicate affective mediation models in a Spanish healthcare context and underscore the systemic relevance of psychological vulnerability in chronic pain. From a public health perspective, integrating routine psychological screening in pain services may strengthen risk stratification, support safer opioid prescribing, and promote more integrated models of care. Consideration of gender differences may further enhance equity and precision in chronic pain management policies.