Use and perceived usefulness of a just-in-time resonance breathing intervention adjunct for substance use disorder: Contextual and physiological predictors.

Craving for alcohol and other drugs is often described as a momentary hyperarousal state that interferes with one's ability to use top-down strategies. As such, it may be best interrupted 'in the moment' through bottom-up modulation. We recently reported that episodic resonance paced breathing (eRPB) delivered via mobile phone app as an add-on to outpatient treatment for substance use disorder (SUD) was effective at dampening craving over the course of an 8-week intervention (NCT#02579317). However, not all participants engaged with the eRPB app and there was high intra- and inter-individual variability in weekly ratings of usefulness. Here we examined baseline demographic, physiological, and psychiatric measures as well as time-varying exposure to positive, negative, and temptation craving triggers as predictors of frequency of eRPB app use and ratings of usefulness. Seventy-seven outpatient women were randomized to an eRPB (0.1 Hz) or a faster paced breathing sham (0.23 Hz) condition. Baseline measures were assessed within the first 3 weeks of treatment entry prior to randomization. App use frequency, ratings of usefulness, and trigger exposure were measured weekly throughout the intervention. Variables were entered into marginal means models with forward stepwise model selection and examined as predictors of use and usefulness. Frequent app use was associated with a lifetime alcohol use disorder (AUD) diagnosis (p = 0.026), higher ratings of usefulness (p < 0.001), and fewer exposures to positive triggers (e.g., celebration, socialization; p < 0.001). There was a trend-level association between frequency of app use and greater cardiovascular capacity at baseline (p = 0.088). Higher ratings of usefulness were associated with greater exposure to negative triggers (e.g,. loneliness, frustration; p < 0.001) and parasympathetic dysregulation at baseline (p = 0.05). A positive relationship between app use frequency and ratings of usefulness was present only in the eRPB group (p = 0.045). Matching ideal candidates and moments to an arousal modulation anti-craving intervention can help streamline screening and implementation of eRPB in the treatment of SUD. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT02579317, identifier NCT02579317.

Cognitive training in recently-abstinent individuals with alcohol use disorder improves emotional stroop performance: Evidence from a randomized pilot trial.

BACKGROUND: Cognitive training interventions appear capable of improving alcohol-associated neurobehavioral deficits in recently detoxified individuals. However, efficacy remains incompletely characterized in alcohol use disorder (AUD) and available data address only non-affective cognitive outcomes; enhancement of social cognition remains uninvestigated. We utilized a training paradigm in which successfully ignoring emotionally-valent stimuli benefitted task performance. We hypothesized trained individuals would display improvements in an affective inhibitory control task, and that individuals trained with high valence (relative to neutral) stimuli would evince greater improvement. METHODS: 42 recently detoxified inpatients with AUD were assigned to one of three groups (Emotional Training, Neutral Training, or Treatment as Usual [TAU]). Training consisted of two computerized working memory tasks (dual-modality n-back task; attend/ignore task) which included task-irrelevant stimuli (emotional vs. neutral). Post-training performance efficiency (indexing speed-accuracy tradeoffs) in an emotional Stroop task was the outcome of interest. RESULTS: Significant group by time interactions were detected for emotional Stroop performance, supporting our hypothesis that trained groups would exhibit greater improvement than TAU controls (F[2,39]=8.61, p < .01). Additionally, the emotional training condition appeared to result in greater improvement relative to neutral training (F[1,26]=4.98, p < .01). CONCLUSION: Results are consistent with current literature suggesting the potential of training to enhance cognitive recovery in early abstinence. Findings inform the development of training protocols, suggesting integration of task-irrelevant distractor stimuli in training may enhance cognitive control outcomes. Further, they expand the relevant domains for application of training approaches, providing novel evidence that among individuals with AUD, training-associated benefits may extend to social cognitive domains.

Effects of arousal modulation via resonance breathing on craving and affect in women with substance use disorder.

BACKGROUND: Craving for alcohol and other drugs is a complex in-the-moment experience that involves within-person changes in physiological arousal and affect. We evaluated the utility of a just-in-time, self-administered resonance breathing smartphone application (app) to reduce craving and improve affect in women during outpatient treatment for substance use disorders (SUD). METHODS: Women (N = 57) receiving outpatient addiction treatment were randomized to practice either cardiovascular resonance breathing (0.1 Hz/6 breaths per minute) or a sham (∼0.23 Hz/14 breaths per minute) in the face of urges over an 8-week intervention. Craving (Penn Alcohol Craving Scale) and affect (Positive and Negative Affect Scale) were collected weekly throughout the intervention. App data were uploaded weekly to assess frequency of use. Generalized Estimated Equations modeled craving and affect as a function of group randomization and app use frequency across the 8-week intervention. FINDINGS: Higher levels of craving were associated with more frequent app use. The group X app use interaction was significant for craving. Frequent app use during the intervention phase was associated with lower craving levels in the resonance breathing group relative to the sham group over the 8-week intervention. There was no effect of app use frequency on affect measures. CONCLUSIONS: Women assigned to practice sham breathing who used the intervention frequently experienced elevations in craving that are commonly reported during outpatient SUD treatment. Women assigned to resonance breathing who used the intervention frequently did not experience such increases. Resonance breathing may be protective against triggers in outpatient treatment. Physiological mechanisms are discussed.

Intimate partner violence, substance use, and health comorbidities among women: A narrative review.

Exposure to intimate partner violence (IPV), including physical, sexual, and psychological violence, aggression, and/or stalking, impacts overall health and can have lasting mental and physical health consequences. Substance misuse is common among individuals exposed to IPV, and IPV-exposed women (IPV-EW) are at-risk for transitioning from substance misuse to substance use disorder (SUD) and demonstrate greater SUD symptom severity; this too can have lasting mental and physical health consequences. Moreover, brain injury is highly prevalent in IPV-EW and is also associated with risk of substance misuse and SUD. Substance misuse, mental health diagnoses, and brain injury, which are highly comorbid, can increase risk of revictimization. Determining the interaction between these factors on the health outcomes and quality of life of IPV-EW remains a critical need. This narrative review uses a multidisciplinary perspective to foster further discussion and research in this area by examining how substance use patterns can cloud identification of and treatment for brain injury and IPV. We draw on past research and the knowledge of our multidisciplinary team of researchers to provide recommendations to facilitate access to resources and treatment strategies and highlight intervention strategies capable of addressing the varied and complex needs of IPV-EW.

Addressing Structural Racism in Psychiatry With Steps to Improve Psychophysiologic Research.

Importance: The American Medical Association has acknowledged the public health threat posed by racism in medicine. While clinicians in psychiatry have echoed the sentiment, the research community has largely been silent. Current understanding of the biological domains that underlie psychiatric disorders was historically established by studying White populations, often leaving widely used treatments ineffective for Asian, Black, Hispanic, Indigenous, and other racial and ethnic minority individuals. This article addresses how undersampling of racial and ethnic minority individuals has led to overgeneralized physiological findings, the implications for development of psychiatric treatments, and steps to improve service to racially diverse communities. Observations: Three primary observations regarding differences associated with race and ethnicity have been addressed in the existing psychiatric research: misdiagnosis, medication nonadherence, and treatment efficacy and expression of adverse effects. While cultural factors have been discussed as potential factors associated with these differences, a lack of understanding of physiologic systems may be foundational to each of these issues. Recent evidence points to race differences in psychophysiological measures, likely attributed to factors including the lived experience of racism as opposed to inherent biological differences. This mounting evidence supports a reassessment of existing work to examine potential divergent patterns within racial and ethnic groups. The following strategies may improve understanding of the influence of racism on physiology, allowing clinicians to better address psychiatric symptoms and improve existing treatment approaches. Thus, psychiatric researchers need to (1) understand the historic and current terminology for race and ethnicity and use appropriate terms and categories as defined by sociologists, population health experts, and databases while respecting individuals' right to self-identify, (2) refine research questions, and (3) reexamine research data to determine whether patterns observed in largely White populations can extend to other groups. To appropriately implement these steps, researchers must accept the discomfort that accompanies growth, invite scientists from diverse backgrounds to participate, and use resources to increase diversity in recruitment of study participants. This will require a commitment from funding agencies to provide adequate support to recruit and investigate large, diverse samples. Conclusions and Relevance: To create more suitable medical treatments and improve the quality of care received by those with psychiatric conditions, further discussion is needed surrounding the physiologic toll that racism has had on multiple generations of racial and ethnic minority groups and how that may alter responsivity to biobehavioral interventions. To better inform psychiatric research, the resources provided must be expanded, basic physiologic studies should be replicated with more diverse samples and adequate analyses, and psychiatry scientists must reconsider approaches to clinical research.

SUBSTANCE USE AND ADDICTION AFFECT MORE THAN THE BRAIN: THE PROMISE OF NEUROCARDIAC INTERVENTIONS.

Purpose of Review: Addiction and excessive substance use contribute to poor mental and physical health. Much research focuses tightly on neural underpinnings and centrally-acting interventions. To broaden this perspective, this review focuses on bidirectional pathways between the brain and cardiovascular system that are well-documented and provide innovative, malleable targets to bolster recovery and alter substance use behaviors. Recent Findings: Cardiovascular signals are integrated via afferent pathways in networks of distributed brain regions that contribute to cognition, as well as emotion and behavior regulation, and are key antecedents and drivers of substance use behaviors. Heart rate variability (HRV), a biomarker of efficient neurocardiac regulatory control, is diminished by heavy substance use and substance use disorders. Promising evidence-based adjunctive interventions that enhance neurocardiac regulation include HRV biofeedback, resonance paced breathing, and some addiction medications. Summary: Cardiovascular communication with the brain through bidirectional pathways contributes to cognitive and emotional processing but is rarely discussed in addiction treatment. New evidence supports cardiovascular-focused adjunctive interventions for problematic substance use and addiction.

Retrospective Hair Cortisol Concentrations from Pretreatment to Early Recovery in Alcohol Use Disorder.

Cortisol profiles are known to vary across phases of alcohol use disorder (AUD; e.g. chronic use, withdrawal and early/sustained recovery). These patterns have largely been established through between-subjects contrasts. Using a segmental hair cortisol concentrations (HCC) approach, retrospective longitudinal analyses are feasible. Here, we examine monthly cortisol secretion in treatment-seekers with AUD from alcohol use to abstinence. At ~6 weeks of recovery we collected hair samples from individuals with moderate-to-severe AUD. We examined HCC from three consecutive segments; proximal to the scalp representing the most recent month (sustained abstinence from alcohol), the midsegment representing the previous month in which abstinence was attained, and the distal segment representing 2 months prior during active drinking. Analyses examined main and interactive effects of segment and sex, controlling for monthly alcohol consumption. Best fit by a quadratic shape, within-subject change was significant (F1,15 = 5.27, P = 0.04, ηpartial2 = 0.26). The distal and midsegments did not differ from one another (P = 0.51). The proximal segment was significantly lower than both the distal (M∆ = 0.200, P = 0.004) and mid (M∆ = 0.175, P < 0.001) segments. An effect of sex approached significance suggesting women had modestly higher HCC than men (MWOMEN = 1.37 vs. MMEN = 1.02, P = 0.10). Consistent with previous cross-sectional reports, these data confirm nonlinear patterns of cortisol accumulation with elevations apparent during periods of alcohol consumption and a decrease in abstinence. Capturing these within-subject patterns via HCC trajectories may serve as a valuable resource in identifying profiles associated with increased risk and post-treatment outcomes.

The impact of emotional face stimuli on working memory performance among men and women with alcohol use disorder.

BACKGROUND: Individuals with alcohol use disorder (AUD) often display compromise in emotional processing and non-affective neurocognitive functions. However, relatively little empirical work explores their intersection. In this study, we examined working memory performance when attending to and ignoring facial stimuli among adults with and without AUD. We anticipated poorer performance in the AUD group, particularly when task demands involved ignoring facial stimuli. Whether this relationship was moderated by facial emotion or participant sex were explored as empirical questions. METHODS: Fifty-six controls (30 women) and 56 treatment-seekers with AUD (14 women) completed task conditions in which performance was advantaged by either attending to or ignoring facial stimuli, including happy, neutral, or fearful faces. Group, sex, and their interaction were independent factors in all models. Efficiency (accuracy/response time) was the primary outcome of interest. RESULTS: An interaction between group and condition (F1,107 = 6.03, p < .02) was detected. Individual comparisons suggested this interaction was driven by AUD-associated performance deficits when ignoring faces, whereas performance was equivalent between groups when faces were attended. Secondary analyses suggested little influence of specific facial emotions on these effects. CONCLUSIONS: These data provide partial support for initial hypotheses, with the AUD group demonstrating poorer working memory performance conditioned on the inability to ignore irrelevant emotional face stimuli. The absence of group differences when scenes were to be ignored (faces remembered) suggests the AUD-associated inability to ignore irrelevance is influenced by specific stimulus qualities.

Alcohol Use Disorder Masks the Effects of Childhood Adversity, Lifetime Trauma, and Chronic Stress on Hypothalamic-Pituitary-Adrenal Axis Reactivity.

BACKGROUND: Individuals with alcohol use disorder (AUD) and those who have experienced traumas or chronic stress exhibit dysregulated hypothalamic-pituitary-adrenal (HPA) axis reactivity. Whether and how trauma and stress histories interact with AUD to affect HPA axis reactivity has not been assessed. METHODS: In the present study, 26 healthy male controls and 70 abstinent men with AUD were administered a pharmacologic probe [ovine corticotropin-releasing hormone (oCRH)] and psychosocial stressor to assess HPA axis reactivity. Plasma adrenocorticotropin hormone (ACTH) and cortisol were assessed every 10-20 minutes. Hierarchical clustering of multiple measures of trauma and stress identified 3 distinct clusters: childhood adversity, lifetime trauma, and chronic stress. General linear model procedures were used to examine main effects of group (AUD/control) and interaction effects of the 3 clusters upon net-integrated ACTH and cortisol response. RESULTS: We found that higher levels of childhood adversity, lifetime trauma, and chronic stress were each associated with blunted oCRH-induced ACTH reactivity in controls, but not in the AUD group. Recent chronic stress within the prior 6 months had the strongest influence upon ACTH reactivity in the control group, and lifetime trauma, the least. CONCLUSIONS: Childhood adversity, lifetime trauma, and chronic stress likely exert persistent, measurable effects upon HPA axis functioning in healthy controls. This association appears to be masked in individuals with AUD, potentially confounding studies examining the effects of stress, adversity, and/or trauma upon the HPA axis in this population during the protracted withdrawal phase of recovery. Future work targeting stress exposure and reactivity should consider the heightened effect of previous alcohol use relative to past adversity and trauma.

The Efficacy of Lidocaine in Disrupting Cocaine Cue-Induced Memory Reconsolidation.

RATIONAL: Cue-induced craving memories, linked to drug-seeking behaviors, require key molecular processes for memory reconsolidation. Lidocaine, a sodium channel blocker, inhibits NMDA receptor activation and suppresses nitric oxide and ERK production. These processes are required for memory re-consolidation; inhibiting them may reduce cue-related craving memories in cocaine dependent subjects. OBJECTIVES: To assess the efficacy of lidocaine in decreasing cue-induced cocaine craving and cocaine use. METHODS: Treatment-seeking cocaine-dependent participants (n = 33, 25 men) were recruited. Personalized craving and relaxation scripts were developed. Participants were then randomly assigned in a double-blind design to either receive intravenous lidocaine immediately following a cocaine craving script (lidocaine/craving), saline following a craving script (saline/craving), or lidocaine following a relaxation script (lidocaine/relax). One week following the infusion, cue-induced craving was assessed in the same paradigm without an infusion. Cocaine use and craving were assessed for 4 weeks following infusion. RESULTS: The administration of lidocaine during craving induction (lidocaine/craving) did not decrease cue-induced craving during craving reactivation one week later or craving and cocaine use over the 4-week follow-up period compared to the saline/craving group. There were no significant differences in craving and cocaine use between the lidocaine/relax and saline/craving groups. CONCLUSION: Lidocaine administered following craving induction did not decrease subsequent cue-induced craving or cocaine use. Blocking the reconsolidation of craving-related memories with pharmacological agents remains an important area of investigation.

Working Memory Performance Following Acute Alcohol: Replication and Extension of Dose by Age Interactions.

OBJECTIVE: Despite the substantial number of older adult drinkers, few studies have examined acute alcohol effects in aging samples. We have explored these interactions across a variety of neurobehavioral domains and modalities and have consistently observed age-contingent vulnerabilities to alcohol-associated decrements in neurobehavioral functions. However, these studies have not been sufficiently powered to address sex differences, and, thus far, no attempt has been made to replicate results. The current study addresses these gaps. METHOD: The study used a double-blind, placebo-controlled, factorial design with two age groups (older, 55-70 years; younger, 25-35 years) and three doses (target breath alcohol concentrations: .00, .04, and .065 g/dl). Replication analyses used an independent sample (n = 90) to replicate age-contingent alcohol effects reported by Boissoneault (n = 90). Samples were combined (N = 180; 91 women) to enable sex analyses. The dependent measure was performance efficiency in a visual working memory task. RESULTS: A complex interaction between sex, age, and dose, F(2, 178) = 4.15, p = .02, appeared driven by age-contingent divergence in working memory performance, which was most pronounced between women at the .065 dose, t(28) = 4.61, p < .01, d = 1.68. Replication analyses revealed a pattern of age differences consistent with previous results, although the previously reported age by alcohol interaction failed to reach statistical significance. CONCLUSIONS: Results provide further support for the hypothesis that neurobehavioral effects of acute alcohol are age dependent and offer evidence that this interaction may be moderated by sex. Extensions of this work are needed to identify underlying processes and ascertain the functional impact of these effects on the health and well-being of aging adult drinkers.

Emotional Face Processing among Treatment-Seeking Individuals with Alcohol Use Disorders: Investigating Sex Differences and Relationships with Interpersonal Functioning.

BACKGROUND: Individuals in treatment for alcohol use disorder (AUD) display deficits across a broad range of cognitive processes. Disruptions in affective processing are understudied, but may be particularly important for interpersonal functioning and post-treatment adaptation. In particular, the role of sex in AUD-associated emotion processing deficits remains largely unaddressed and was a focus of the current investigation. METHODS: Fifty-six treatment seekers with AUD and 54 healthy community controls (N = 110) were administered an emotional face discrimination task. Non-affective tasks included a sex-discrimination task and two brief measures of executive functioning. Two measures of interpersonal function were included. RESULTS: Emotion processing deficits were evident among women with AUD relative to other groups. This sex-contingent relationship was not observed in measures of executive function, sex-discrimination or interpersonal problems, although individuals with AUD performed more poorly on these measures. CONCLUSIONS: Results were consistent with extant literatures examining cognitive, affective and interpersonal functioning among individuals with AUD, and provided novel evidence of vulnerability to alcohol-associated deficits in emotion processing among women. While similar sex-contingent effects were not apparent among other measures, results support modest interrelationships, specifically including the import of emotion processing to interpersonal functioning in AUD. These data offer guidance for further systematic investigation and highlight important considerations for future relapse-prevention and recovery-facilitation efforts.

Differences in pituitary-adrenal reactivity in Black and White men with and without alcohol use disorder.

BACKGROUND: Treatment-seeking men with alcohol use disorder (AUD) classically exhibit a blunted hypothalamic-pituitary-adrenal (HPA) axis response to pharmacologic and behavioral provocations during the early phases of abstinence from alcohol. Independent of alcohol, a significant muting of HPA axis reactivity is also observed among racial minority (e.g. Black) individuals. The effect of AUD upon the altered HPA axis response of racial minority individuals has not been explored. The current work represents a secondary analysis of race and AUD status among a sample of men. METHODS: Healthy male controls (17 White, 7 Black) and four-to six-week abstinent men with AUD (49 White, 13 Black) were administered a psychosocial stressor and two pharmacologic probes [ovine corticotropin releasing hormone (oCRH) and cosyntropin] to assess HPA axis reactivity. Plasma cortisol and adrenocorticotropin hormone (ACTH) were assessed at 10-20 min intervals prior to and following behavioral and pharmacological stimulation. Basal and net-integrated responses following provocations were analyzed to identify potential group differences. A measure of childhood adversity was also obtained to consider the implications of prior stressors upon HPA axis function. RESULTS: A three-fold increase in oCRH-induced ACTH was seen in Black men relative to White men regardless of AUD status. Adversity exerted a dampening effect on this pituitary sensitivity within Black controls only. Adjusted for adversity, a significant blunting effect of AUD status on ACTH reactivity was identified within White participants following oCRH. No group differences were present following cosyntropin administration. In response to the psychosocial stressor, White, but not Black, men with AUD experienced the expected blunting of cortisol reactivity relative to White controls. Rather, Black men with AUD exhibited greater cortisol reactivity relative to White men with AUD. CONCLUSIONS: Differences in HPA axis reactivity associated with race were present in men with and without AUD. Explanatory biological mechanisms of the relationship between alcohol use and/or stress, in both healthy and unhealthy populations, may require a reassessment in different racial populations.

Brain intrinsic network connectivity in individuals with frequent tanning behavior.

BACKGROUND: Emergent studies suggest a bidirectional relationship between brain functioning and the skin. This neurocutaneous connection may be responsible for the reward response to tanning and, thus, may contribute to excessive tanning behavior. To date, however, this association has not yet been examined. OBJECTIVES: To explore whether intrinsic brain functional connectivity within the default mode network (DMN) is related to indoor tanning behavior. METHODS: Resting state functional connectivity (rsFC) was obtained in twenty adults (16 females) with a history of indoor tanning. Using a seed-based [(posterior cingulate cortex (PCC)] approach, the relationship between tanning severity and FC strength was assessed. Tanning severity was measured with symptom count from the Structured Clinical Interview for Tanning Abuse and Dependence (SITAD) and tanning intensity (lifetime indoor tanning episodes/years tanning). RESULTS: rsFC strength between the PCC and other DMN regions (left globus pallidus, left medial frontal gyrus, left superior frontal gyrus) is positively correlated with tanning symptom count. rsFC strength between the PCC and salience network regions (right anterior cingulate cortex, left inferior parietal lobe, left inferior temporal gyrus) is correlated with tanning intensity. CONCLUSION: Greater connectivity between tanning severity and DMN and salience network connectivity suggests that heightened self-awareness of salient stimuli may be a mechanism that underlies frequent tanning behavior. These findings add to the growing evidence of brain-skin connection and reflect dysregulation in the reward processing networks in those with frequent tanning.

Effects of acute alcohol and driving complexity in older and younger adults.

RATIONALE: Our previous work demonstrated differential neurobehavioral effects of low-dose alcohol consumption on older and younger adults in a driving simulator. However, the ability to enhance or suppress a response in such context has yet to be examined. OBJECTIVES: The current study contrasted older and younger drivers' responses to specific stimuli (i.e., relevant, irrelevant) in scenarios of differing complexity following low-dose acute alcohol administration. METHODS: Healthy older (55-70) and younger (25-35) adults completed two driving scenarios (i.e., country and metropolis) both before and after consuming beverages targeted to reach peak BrACs of 0.00, 0.04, or 0.065%. Throughout the simulation, participants encountered relevant stimuli (e.g., pedestrians walking into the street) and irrelevant stimuli (e.g., pedestrians walking parallel). Peak deceleration, range of steering, and distance until brake application were assessed within a 450-ft window preceding each stimulus. RESULTS: Following low-dose alcohol consumption, older adults shifted from a strategy using both deceleration and steering to relying solely on deceleration in responding to relevant stimuli in the country. Older adults under both low and moderate alcohol conditions displayed an inability to withhold responses to irrelevant stimuli in the metropolis. CONCLUSION: These findings are consistent with our prior work showing differential effects of low-dose alcohol on older, relative to younger, adults. The interactive effects of age and alcohol, however, depend on stimulus type and environmental complexity. Continued investigation of neurobehavioral mechanisms in ecologically valid paradigms is necessary for understanding the implications of the combined impairing effects of alcohol and older age.

Dopamine efflux in response to ultraviolet radiation in addicted sunbed users.

Compulsive tanning despite awareness of ultraviolet radiation (UVR) carcinogenicity may represent an "addictive" behavior. Many addictive disorders are associated with alterations in dopamine (D2/D3) receptor binding and dopamine reactivity in the brain's reward pathway. To determine if compulsive tanners exhibited neurobiologic responses similar to other addictive disorders, this study assessed basal striatal D2/D3 binding and UVR-induced striatal dopamine efflux in ten addicted and ten infrequent tanners. In a double-blind crossover trial, UVR or sham UVR was administered in separate sessions during brain imaging with single photon emission computerized tomography (SPECT). Basal D2/D3 receptor density and UVR-induced dopamine efflux in the caudate were assessed using (123)I-iodobenzamide ((123)I-IBZM) binding potential non-displaceable (BPnd). Basal BPnd did not significantly differ between addicted and infrequent tanners. Whereas neither UVR nor sham UVR induced significant changes in bilateral caudate BPnd in either group, post-hoc analyses revealed left caudate BPnd significantly decreased (reflecting increased dopamine efflux) in the addicted tanners - but not the infrequent tanners - during the UVR session only. Bilateral ∆BPnd correlated with tanning severity only in the addicted tanners. These preliminary findings are consistent with a stronger neural rewarding response to UVR in addicted tanners, supporting a cutaneous-neural connection driving excessive sunbed use.