A review of the neurobiological underpinning of comorbid substance use and mood disorders

•Neurobiological associations for comorbid affective and substance disorders are not fully elucidated.•Neuroimaging supports dopaminergic dysfunction in depression and tobacco use.•Positive association between alcohol use and hippocampal glutamate concentrations.•Alcohol may further reduce prefrontal glutamate concentrations in comorbid bipolar disorder.•Inflammation and oxidative stress biomarkers were identified in comorbid depression and tobacco use.