Mechanism-based subtypes of problematic use of the internet and corresponding neurobehavioral characteristics among...

The global prevalence of problematic use of the internet (PUI) has increased over time, particularly among youth. To enhance the efficacy of treatments and identify personalized intervention targets, it is important to classify subtypes based on differences in underlying mechanisms rather than solely on symptom severity. This study aimed to identify reliable subtypes of PUI among youth by examining three neurofunctional domains commonly implicated in addictive behaviors-reward processing, negative emotionality, and executive function - and to assess how the identified subtypes differed regarding clinical characteristics and resting-state functional connectivity.

Data were drawn from the Healthy Brain Network (HBN) study, comprising 484 children and adolescents (ages 6-21; 37.4% female), including 242 individuals with PUI and 242 matched controls. Latent profile analysis, along with sensitivity analyses, was conducted on phenotypic data reflecting the three addiction-related domains. The resulting subtypes were then evaluated for clinical characteristics and resting-state brain functional connectivity to consider their clinical and biological relevance.

Three stable PUI subtypes were identified: a 'High approach with low executive function' subtype characterized by steeper delay discounting and poorer executive function, frequently co-occurring with learning disorders (n = 20); a 'Negative emotionality' subtype with elevated negative affect, frequently co-occurring with affective disorders (n = 37); an 'Emotional stress' subtype that only exhibited higher negative affect compared to matched controls and showed no marked dysfunction across other domains (n = 185). Furthermore, each subtype demonstrated distinct patterns of resting-state functional connectivity.

The findings provide empirical evidence that youth with PUI are heterogeneous across three core neurofunctional domains, offering insights for the development of more tailored, subtype-specific interventions.