Identifying underlying mechanisms of social functioning challenges in OUD is critical for developing more effective interventions. Our study found that patients in recovery from OUD who exhibit some level of social impairment have higher impulsivity scores, greater depressive symptoms, and increased PFC activity when attempting to regulate their impulses compared to those without any detectable social impairment. We also found that, when controlling for depressive symptoms, ACEs moderated the relationship of social impairment and impulsivity, such that those with a higher degree of trauma exposure displayed increased impulsivity and decreased social functioning. These results highlight the importance of integrative care framed in trauma informed approaches, taking into account not only mental health symptom burden but also trauma history to help promote social functioning, which facilitates the ability to build and form relationships critical for recovery.
Previous literature has found that impulsivity is both a risk factor and a contributor to the maintenance of OUD (54), with some highlighting that more impulsivity is linked to poorer treatment outcomes (55). However, very few studies investigate what lies behind this self-regulation challenge and how it further impacts patients during recovery. One study traced negative indicators of social functioning in patients recovering from OUD (56), analyzing demographic (age, gender, race, etc.) as well as socioeconomic (employment and residential status) factors. Yet, the study did not explore potential behavioral variables such as impulsivity. Inhibition is thought to be central to controlling social behavior (17). This has been corroborated in prior studies such as the one authored by Von Hippel & Gonsalkorale (2005), which revealed that cognitive inhibition predicted more appropriate social behavior (6). Our study extends this idea to those in recovery, as increased impulsivity is linked to social impairment. Therefore, beyond being a risk factor and a contributor to OUD, impulsivity also further impacts patients’ relationships. Since patient-provider relationships and support networks (57) are crucial during treatment, impulsivity represents a drawback in recovery.
This study adds to this initial finding, exploring the potential mechanisms that underlie this relationship. The added layer of trauma might impact the impulsivity of those in recovery (58). Peck et al. (2022) found that those with comorbid Post-Traumatic Stress Disorder (PTSD) and OUD were more impulsive in the context of negative emotions compared to those in recovery without PTSD (58). Furthermore, research has pointed out that experiencing adversity during childhood is linked to poor social outcomes (59) and impulsivity (60, 61). Aligned with these ideas, our study found that, when controlling for depressive symptoms, the relationship between impulsivity and social functioning is moderated by childhood trauma history. To our knowledge, this was the first study to find the moderation role of childhood adversity in the context of social functioning and impulsivity for those in recovery. This result suggests that the relationships between trauma, impulsivity, and OUD might be additive.
It is not surprising that those with social impairment revealed more significant levels of depression symptoms. Previous studies have found that, in those who have SUD, social impairment is more prominent when it is comorbid with mental health issues (62, 63). Considering its relevance in the context of OUD, depressive symptoms were considered at every step of our analysis to explore potential relationships that exist beyond its notorious effects. As discussed, childhood adversity emerged as a moderator only when controlling the effects of depression symptomology. This may indicate that trauma history affects patients above and beyond the mental health burden alone. Although unexpected, this finding aligns with previous literature that uncovered the broader impact of trauma history on survivors, surpassing mental health concerns (64).
In this study, we explored brain activity during an affective inhibitory task to better understand the neural underpinnings of social functioning. In particular, we aimed to understand if those with social impairment had differential brain activity while engaging in impulse control. While the socially impaired group exhibited higher levels of self-reported impulsivity, there were no differences of performance on the fNIRS Go-No-go task. The lack thereof is not unique to this study; similar results have been reported in other studies employing this paradigm (65–67). This result could be attributed to the task's inherent simplicity, corresponding to the observed ceiling effect on performance. Conversely, this facilitated the identification of notable differences in brain activation during comparable behavior.
The SI group revealed greater activation in the dorsolateral (Optodes 1 and 15), ventrolateral (Optode 16), and ventromedial (Optode 10) PFC compared to the N-SI group. In line with existing literature (68), differences in neural activation during response inhibition were primarily found in the lateral regions of the PFC. Experiments with clinical populations that exhibit impulse control challenges, such as Attention-Deficit/Hyperactivity Disorder (ADHD) and mania, also revealed activation differences in the ventrolateral (69, 70) and dorsolateral (67) PFC during the Go-No/Go task. The studies, however, reported attenuated activation of these regions for the clinical groups compared to control during impulse inhibition, while in our sample, the socially impaired group displayed increased activation. One of the primary differences between this study and the others is the affective nature of our Go/No-Go task, which may elicit higher responses in those with impairment.
The implication of both right (Optode 1) and left (Optode 15) dorsolateral PFC aligns with its established role in top-down regulation of behavior, especially in task-relevant responses (71). Notably, research has pointed out that directly stimulating this region can improve response inhibition (72, 73). Hence, it would be reasonable to assume that detected heightened activation corresponds to enhanced inhibition. In our sample, however, the enhanced activation of the dorsolateral PFC did not align with increased performance. One possible explanation for this lies in the suggested role of the dorsolateral PFC in cognitive flexibility. It posits that increased activation of this region is associated with adaptive cognitive control (74, 75), helping implement adjustments to adapt to errors or conflicts detected. This could represent a compensatory mechanism, as Weissman et al. (2008) proposed that the role of the dorsolateral PFC in adaptive cognitive control extends to social contexts (76). Individuals with social impairment may require greater mental effort to adapt their behavior, inhibit responses, and adjust to social norms. This might provide a hint for resilience pathways: those with social impairment may have learned how to be resilient to underlying neurological differences – as revealed by the equivalent performance in the task – but are still making more effort to inhibit their impulses.
Limitations and Future Directions
Considering this was a secondary analysis of a modestly sized sample, it is crucial to replicate these findings with a larger sample. Moreover, study variables should be analyzed in a more gender-balanced context, as studies have found sex differences impact social functioning in those in recovery (4). Beyond the sample limitations, our study is limited by the complexity of studying social functioning. Due to its relative neglect in research, there are considerable challenges with operationalizing the concept, finding a standardized measure, and establishing an effective methodology for its study. Future research is needed in which participants are recruited based on their social functioning levels while implementing a standardized measure and an experimental approach to evaluate this variable comprehensively. While validated measures were used, the impact of social desirability and self-report items should still be considered. Finally, despite being a more trauma-informed and community-engaged option for neuroimaging studies, fNIRS restricted our analysis solely to the PFC. Therefore, more investigation is needed, taking advantage of other technologies to analyze these relationships in different brain areas. Despite these limitations, this study is, to our knowledge, the first of its kind to uncover impulsivity and childhood trauma as potential variables underlying the social challenges faced by patients in recovery from OUD.
Clinical Implications
Developing and maintaining relationships is a critical ingredient for the recovery process (77, 29). Approaches that take advantage of interpersonal relationships, such as peer recovery support (78), have shown great promise in SUD recovery. However, some patients face more social functioning challenges than others, which possibly hampers their recovery process. This study aims to acknowledge and identify areas for potential intervention that could aid in the recovery journey. Our results reveal that, beyond self-reported impulsivity, these individuals have differential connectivity in their brains, which may help explain the social challenges they are experiencing. Understanding the neural differences in those with and without social functioning challenges can help us destigmatize patients in recovery.
Additionally, as underscored by Van Reekum et al. (2020), there is an evident gap in addressing the social needs of patients with OUD during recovery (4). Impulsivity, along with corresponding neural alterations, may, hence, represent a new treatment target. Considering the impact of impulsivity on social impairment varies depending on the history of childhood trauma, it is crucial to implement a trauma-informed, holistic, transdiagnostic approach to OUD recovery. This was particularly true when looking beyond the impact of mental health symptoms, which highlights the importance of, in addition to mental health evaluations, implementing trauma history screening before, and throughout the development of the recovery care plan. This could help generate more personalized and productive strategies to support the social functioning needs of those in recovery.