Difficulty in Attention Switching and Its Neural Basis in Problematic Smartphone Use

Area of Science:

• Neuroscience
• Psychiatry
• Digital Health

Background:

• Problematic smartphone use (PSU) is characterized by excessive engagement, impacting daily function.
• PSU is associated with attentional control deficits and altered reward processing.
• The nucleus accumbens (NAcc), part of the reward system, may play a role in difficulty disengaging from digital content.

Purpose of the Study:

• To investigate the relationship between nucleus accumbens (NAcc) volume, attentional switching, and nighttime screen time in individuals with problematic smartphone use (PSU).
• To explore the neurobiological underpinnings of excessive smartphone engagement and its impact on cognitive functions.

Main Methods:

• Fifty-three participants (≥13 years) diagnosed with PSU underwent psychological assessments, MRI scans, and smartphone logging.
• Attentional switching was assessed using the Autism Spectrum Quotient subscale.
• Nighttime screen time (00:00-06:00) was objectively measured; NAcc volumes were normalized to gray matter volume.

Main Results:

• Difficulty in attention switching correlated with larger right NAcc volume and increased nighttime screen time.
• Right NAcc volume was positively correlated with nighttime screen time.
• Regression analysis indicated that right NAcc volume predicted nighttime screen time, independent of attentional switching.

Conclusions:

• A larger right NAcc volume is an independent predictor of prolonged nighttime smartphone use in individuals with PSU.
• Structural variations in the NAcc are associated with impaired attentional switching and may underlie difficulty disengaging from digital content.
• Combining neurobiological, cognitive, and behavioral data provides a comprehensive framework for understanding PSU.