Nursing care supervision: A qualitative study of staff and auxiliary nurses' experiences in Limpopo province.

The rapid development of internet technology has dramatically changed the landscape of sexual stimulation, making pornography more accessible, anonymous, and affordable than ever before. While the majority of individuals consume pornography occasionally for entertainment without experiencing functional impairment (; ), a notable minority develop persistent and uncontrollable problematic pornography use (PPU). PPU is characterized by compulsive consumption of pornography, such as excessive preoccupation with pornography, repeated unsuccessful attempts to reduce use, continued use despite negative consequences, and reduced engagement in other rewarding activities (; ). Recent epidemiological studies indicate that the prevalence of PPU ranges from 3% to 10% among men and 1% to 7% among women (; ; ). PPU, which is a subtype of compulsive sexual behavior disorder (CSBD), has been officially recognized in the ICD-11 as an impulse control disorder, highlighting its clinical and public health significance (; ). However, growing empirical evidence supports conceptualizing CSBD and PPU within an addiction framework, rather than viewing them solely from an impulse-control perspective (; ; ; ). Despite increasing research, the core neurobiological mechanisms underlying PPU remain insufficiently understood, hindering the development of targeted interventions. A large body of neurobiological models supports the view that addiction is fundamentally characterized by imbalanced reward processing (; ; ). This central framework suggests that addictive behaviors arise from two complementary alterations in the brain’s reward system: heightened salience of addiction-related stimuli and blunted responsiveness to natural rewards. This dual-pathway model is supported by several influential theories of addiction. The incentive sensitization theory proposes that repeated exposure to addictive stimuli progressively enhances the salience of addiction-related cues, transforming them into powerful motivational magnets that elicit intense craving and compulsive approach behaviors (). The impaired response inhibition and salience attribution (IRISA) model extends this framework by emphasizing that addiction involves both hyper-reactivity to addictive cues and hypo-reactivity to natural rewards, which together disrupt inhibitory control and lead to maladaptive decision-making (). Similarly, the reward deficiency hypothesis suggests that inherently reduced sensitivity to natural rewards predisposes individuals to seek highly stimulating artificial rewards, such as drugs or compulsive behaviors, to compensate for dysfunctional reward circuits (). While incentive-sensitization models emphasize the heightened salience of addiction-related rewards and reward-deficit models focus on the reduced responsiveness to natural rewards, neither framework directly examines whether the differential valuation of these two reward types serves as a distinct risk marker for addiction. Instead, a set of complementary perspectives, including behavioral and neuroeconomic models of choice (; ) and computational neuroscience accounts of relative reward coding (), suggests that the relative difference between addiction-related and natural rewards is critical to addiction etiology. Behavioral economic and value-based decision-making frameworks emphasize that reward-seeking behavior is guided by the relative value of options, rather than absolute reward magnitude (). These models propose that the brain encodes a subjective value signal for each option, with addiction involving a biased valuation toward addiction-related rewards (; ). Computational neuroscience models extend this by formalizing how relative reward differences are dynamically updated via reinforcement learning. Chronic exposure to addictive stimuli progressively widens the gap between addiction-related and natural reward values (). Together, these frameworks suggest that the relative imbalance between addiction-related and natural rewards, rather than either system alone, confers vulnerability to addiction.