Brain iron and mental health symptoms in youth with and without prenatal alcohol exposure

Prenatal alcohol exposure (PAE) negatively affects brain development and increases the risk of poor mental health. We investigated if brain susceptibility, measuring iron, or volume were associated with internalizing or externalizing symptoms in youth with and without PAE. T1-weighted and quantitative susceptibility mapping (QSM) MRI scans were collected for 19 PAE and 40 unexposed participants aged 7.5-15 years. Magnetic susceptibility and volume of basal ganglia and limbic structures were extracted using FreeSurfer. Internalizing and externalizing problems were assessed using the Behavioural Assessment System for Children (BASC-2-PRS). Susceptibility in the nucleus accumbens was negatively associated with internalizing problems, while amygdala susceptibility was positively associated with internalizing problems across groups. In the PAE group, thalamus susceptibility was negatively associated with internalizing problems, and putamen susceptibility was positively associated with externalizing problems. Brain volume was not related to internalizing or externalizing symptoms. These findings highlight that brain iron is related to internalizing and externalizing symptoms differently in some brain regions for youth with and without PAE. Atypical iron levels (high or low) may indicate mental health problems across individuals, and iron in the thalamus and putamen may be particularly important for behaviour in individuals with PAE.