A recent study examined the effects of 72 hours of smartphone restriction on neural activity in young adults, identifying changes in brain regions linked to craving and reward processing.
Researchers, using functional magnetic resonance imaging (fMRI), found increased activation that was most prominent in the nucleus accumbens (NAcc) and anterior cingulate cortex (ACC)—areas in the brain linked to addiction-related cue-reactivity (P < .001). These changes correlated with dopamine and serotonin receptor probabilites (PFDR < .05), suggesting a potential neurochemical basis for smartphone-related craving. Their findings were published in Science Direct.
Researchers recruited 25 right-handed participants aged 18 to 30 years who underwent a 72-hour smartphone restriction period. Baseline and postrestriction assessments included fMRI scans and psychometric evaluations using the Beck Depression Inventory (BDI) and Mannheimer Craving Scale (MaCS).
In the PHONE > NEU condition (smartphone vs neutral stimuli), activation in bilateral NAcc correlated positively with baseline BDI scores, while right NAcc activation correlated with BDI after the restriction period. The right caudate, another brain region associated with reward processing, showed a similar correlation.
In the ON > OFF contrast (active vs inactive smartphone images), a decrease in left middle frontal gyrus and superior parietal lobule activation was observed after the 72 hours of restriction. These reductions correlated negatively with Smartphone Addiction Inventory-I (SPAI-I) sleep interference scores and positively with MaCS total scores—suggesting that decreased smartphone use may improve inhibitory control over compulsive smartphone behaviors.
According to the authors, these findings suggest that changes in reward processing during smartphone restriction may influence mood improvements, particularly in individuals with higher baseline depressive symptoms.
"This might indicate that changes of reward processing during smartphone restriction happen and support improved mood but depend on severity of depressiveness before smartphone restriction," wrote first study Mike M. Schmitgen, PhD, of the Department of General Psychiatry, Center for Psychosocial Medicine, Heidelberg University, and colleagues.
The study’s findings align with prior research on cue reactivity in substance addiction, where increased ACC activation has been observed during withdrawal. The authors noted that smartphone restriction may show parallels to drug abstinence or food cravings, but behavioral craving scores did not significantly change over time (P = .32), suggesting that neural craving signals do not always translate to self-reported experiences.
The researchers acknowledged the study’s limitations, including a modest sample size, lack of an objective verification mechanism for smartphone restriction, and the absence of a third control group with unrestricted smartphone use. They suggested that future studies should explore longer restriction periods and include qualitative assessments of mood and coping strategies.
While the study did not find significant changes in self-reported craving, its fMRI results provide evidence of cue-reactivity–driven neural changes in smartphone users following restriction of device use.
The authors reported no competing interests.
