Latent anger profiles in chronic pain and their associations with current and long-term pain outcomes

Anger, a particularly salient emotion in chronic pain (CP), has been linked to increased symptom severity. However, much of the existing research tends to focus on a unidimensional assessment of anger in CP. The present study addresses this gap by using a data-driven approach (latent profile analysis, LPA) to identify idiosyncratic profiles based on a multidimensional assessment of anger, and examining how these anger profiles associated with pain outcomes cross-sectionally and longitudinally. Data were collected from 735 patients with CP of various etiologies attending the Stanford Pain Management Centers, with 242 completing a follow-up survey about 4-5 months thereafter. We assessed several forms of anger, including state and trait anger, anger expression (anger-in and anger-out), anger control (control-in and control-out), as well as a cognitive facet of anger in CP, namely perceived injustice. Pain variables included pain distribution, pain intensity, pain interference, pain behavior, and physical functions. Emotional distress was assessed using anxiety and depression scales. LPA identified four distinct anger profiles: Low Anger/Low Injustice (LALI, 49%), Low Anger/High Injustice (LAHI, 24%), Moderate Anger/Low Injustice (MALI, 20%), and High Anger/High Injustice (HAHI, 7%). These profiles demonstrated significant associations with pain variables at baseline and follow-up, with perceived injustice emerged as a potential major factor in worsening CP symptoms. Importantly, anger profiles predicted pain outcomes above and beyond anxiety and depression. These findings highlight the unique and multidimensional role of anger in CP, emphasizing the need for emotion-focused interventions that balance adaptive anger expression while mitigating its maladaptive effects.