Serotonin and neurofilament light chain in alcohol-related suicide: Preliminary case observations

Alcohol dependence significantly impacts both physiological and psychological health and is strongly linked to increased suicide attempt. However, the neurobiological mechanisms connecting alcohol use disorder (AUD) to suicidality remain inadequately understood. This study evaluated the severity of alcohol dependence in 24 patients diagnosed with AUD using the Alcohol Use Disorders Identification Test (AUDIT). In parallel, peripheral blood levels of neurofilament light chain (NfL), a bioindicator of neuronal injury, and serotonin, a neurotransmitter implicated in mood regulation and suicidality, were quantified. One patient with a prior history of suicide attempts exhibited markedly elevated plasma NfL levels (1350 pg/ml), greatly exceeding the mean observed in non-suicidal AUD patients (33.06 pg/ml). Despite the absence of detectable brain abnormalities on imaging, the patient presented with a lumbar vertebral burst fracture, suggesting spinal cord trauma as the source of neuronal injury. Moreover, serotonin levels in this individual were substantially reduced (89.41 ng/ml) relative to the group average (340.5 ng/ml). These findings suggest that elevated NfL levels may reflect neural injury originating from spinal, rather than cerebral, sources in AUD patients with suicide attempts. Additionally, reduced serotonin levels may serve as a clinically useful bioindicator to stratify suicide attempt in this population.