The cognitive-serotonergic interface of gaming: understanding how mobile game-play shapes the young adult brain

In recent years mobile gaming has become the preferred leisure activity especially among young adults. Although behavioural and cognitive effects of gaming have been widely examined, far less attention has been given to its biochemical foundations - particularly the role of serotonin, a neurotransmitter crucial for impulse regulation, inhibitory control, and cognitive flexibility. Therefore, in the present study we assessed and compared the cognitive performance and serum serotonin levels among gamers playing action mobile game (AMG) and puzzle mobile game (PMG) genres and also evaluated the predictive role of gaming characteristics on cognition and serum serotonin levels of mobile gamers.

30 participants each, who played ≥5 h/week of respective mobile game genre in past 6 months were recruited into AMG and PMG group. 30 participants who had not played any genre of mobile-game for ≥1 h/week in past 6 months and are non-gamers (NG) were recruited as controls. Sleep quality was assessed using the Pittsburgh sleep quality index (PSQI). Cognitive functions were assessed using pen-paper version of trail making test (TMT), Stroop colour word test (SCWT), letter cancellation test (LCT) and Ruffs figural fluency test (RFFT). Auditory and visual reaction times were recorded with the help of audio-visual reaction timer. Serum serotonin levels were assessed by immunoassay.

Multivariate analysis revealed a significant effect of gaming group on combined cognitive measures (Pillai's trace=0.657, F(26,140)=2.63, p<0.001, η ²=0.328). The action mobile gamers exhibited faster auditory reaction time (ART) compared to the puzzle gamers (p<0.05) as well as had significantly lower serum serotonin levels than both puzzle gamers as well as non-gamers (p<0.001). Regression analyses model showed that gaming characteristics like gaming frequency, duration, age of onset, and expertise, accounted for 22 % of variance in ART (p=0.017) and 66 % of variance in serum serotonin levels (p<0.001).

These findings illustrate a genre-specific effect of mobile gaming on cognitive-serotonergic profile among young adults. Results further demonstrate that both the type and intensity of gameplay contribute to cognitive and neurochemical outcomes. However, no statistically significant differences emerged across groups in broader executive-function tasks suggesting that mobile gaming is not a uniform cognitive stimulus; rather, its effects are selective, genre-dependent, and influenced by the intensity and duration of engagement, linking gameplay behaviour to both cognitive performance and peripheral neurochemical profiles.