The characteristics of fractional amplitude of low frequency fluctuation among first-episode and drug-naive individuals with depressive disorder combined with internet addiction.

BACKGROUND

Major depressive disorder (MDD) and Internet addiction (IA) are common and cause significant impairment, yet their relationship remains unclear. This study aims to explore the neurobiological mechanisms of comorbid MDD and IA and to inform clinical interventions.

METHODS

This study recruited 141 first-episode, drug-naïve MDD patients (72 with IA, 69 without) and 61 healthy controls (HC). Clinical assessments included the Hamilton Depression Rating Scale (HAMD) and Internet Addiction Test (IAT). Resting-state fMRI data were acquired using a 3 T Siemens scanner, and fractional amplitude of low-frequency fluctuations (fALFF) was computed with the Data Processing Assistant for Resting-State fMRI (DPARSF) software. Statistical analyses involved ANOVA, MANCOVA, and partial correlation, with multiple comparisons corrected using the FDR and Bonferroni methods.

RESULTS

Compared to HC group, both MDD + IA and MDD groups exhibited common elevations in fALFF within the left superior medial frontal gyrus and right superior frontal gyrus, alongside reductions in the right middle occipital gyrus. Concurrently, group-specific alterations were identified: MDD + IA had higher fALFF in the right inferior frontal gyrus triangular region, while MDD exhibited lower fALFF in the right postcentral gyrus and left inferior temporal gyrus. MDD + IA had significantly higher fALFF in the left inferior parietal lobule than MDD. Furthermore, fALFF in this region was positively correlated with IAT scores.

CONCLUSIONS

MDD with IA is associated with distinct neurological alterations in frontal and parietal regions. The left inferior parietal lobule may serve as a potential neurobiological marker for MDD comorbid with IA, providing a target for future interventions.