Dopamine efflux in response to ultraviolet radiation in addicted sunbed users

Abstract

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 123I-iodobenzamide (123I-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 ΔBPnd 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.

Indoor Tanning Dependence in Young Adult Women

“…The strength of association was greater than studies reporting comorbidities associated with non-dependent tanning behavior and comparable to those reported for indoor tanning dependence (18, 20, 54). This evidence, in conjunction with research indicating indoor tanning can produce mood-enhancing effects (11, 14, 15), suggests a potential mechanism whereby young women experiencing depressed mood or other psychological distress may indoor tan because it alleviates such symptoms. However, there remains a need for research to understand how psychiatric comorbidity, affect-oriented motives, and indoor tanning dependence unfold over time.…”

“…One hypothesis is that synthesis of β-endorphin as a byproduct of ultraviolet (UV) radiation exposure may produce opioid-like drug response (10). Evidence from pre-clinical (10) and clinical studies (11–16) supports this model of indoor tanning addiction.…”

“…In clinical studies, frequent indoor tanners endorse subjective preference for UV light over sham light when blinded to the source (12, 16), and this preference diminishes with pharmacologic opioid antagonism (16). Exposure to UV light among frequent tanners has been shown to activate reward-based brain regions (13) and to produce increased dopamine response (11) similar to other forms of addiction. Frequent indoor tanners have also been observed to endorse responses characteristic of drug exposure after tanning, such as improved mood and euphoria (14, 15).…”

Review of interventions to reduce ultraviolet tanning: Need for treatments targeting excessive tanning, an emerging addictive behavior.

“…Harrington and colleagues (2012) found that frequent indoor tanners exhibited increases in blood flow to brain areas associated with drug-induced rewards when using UVR tanning beds. A follow-up study provided evidence for dopamine receptor activity in response to UVR exposure among frequent tanners (Aubert et al, 2016). The intensity of this effect was higher among tanners with higher rates of past use.…”

Predictors of tanning dependence in white non‐Hispanic females and males

“…Results from a similarly designed double‐blind study in fibromyalgia patients found a significant positive association between mood (positive effect, well‐being, relaxation) and UV light . In addition, increased activity in the brain regions associated with the experience of reward was observed in subjects when using a UV tanning bed, but not when using a sham tanning bed without UV light, suggesting that UV light may have centrally rewarding properties . This has come to be known as tanning dependence (TD) in the literature.…”