EEG correlates associated with the severity of gambling disorder and serum BDNF levels in patients with gambling disorder

Background and aims: This study aimed to evaluate the association between the severity of pathological gambling, serum brain-derived neurotrophic factor (BDNF) level, and the characteristics of quantitative electroencephalography (EEG) in patients with gambling disorder. Methods: A total of 55 male patients aged 18-65 with gambling disorder participated. The severity of pathological gambling was assessed with the nine-item Problem Gambling Severity Index from the Canadian Problem Gambling Index (CPGI-PGSI). The Beck Depression Inventory and Lubben Social Network Scale were also assessed. Serum BDNF levels were assessed from blood samples. The resting-state EEG was recorded while the eyes were closed, and the absolute power of five frequency bands was analyzed: delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), and gamma (30-50 Hz). Results: Serum BDNF level was positively correlated with theta power in the right parietal region (P4, r =.403, p =.011), beta power in the right parietal region (P4, r =.456, p =.010), and beta power in the right temporal region (T8, r =.421, p =.008). Gambling severity (CPGI-PGSI) was positively correlated with absolute beta power in the left frontal region (F7, r =.284, p =.043) and central region [(C3, r =.292, p =.038), (C4, r =.304, p =.030)]. Conclusions: These findings support the hypothesis that right-dominant lateralized correlations between BDNF and beta and theta power reflect right-dominant brain activation in addiction. The positive correlations between beta power and the severity of gambling disorder may be associated with hyperexcitability and increased cravings. These findings contribute to a better understanding of brain-based electrophysiological changes and BDNF levels in patients with pathological gambling.