“…The latter can be divided into two broad categories: internalizing (e.g., depression, anxiety) and externalizing (e.g., disruptive behaviour, attention problems, hyperactivity) symptoms. Indeed, numerous cross-sectional studies have found that altered HCC was associated with internalizing ( Ford et al, 2019 , Gray et al, 2018 , Lu et al, 2018 , Rietschel et al, 2016 , Sandstrom et al, 2021 , Stalder et al, 2017 ) and externalizing ( Grotzinger et al, 2018 , Kao et al, 2018 , Pauli-Pott et al, 2017 , Pauli-Pott et al, 2019 , Schloß et al, 2018 , White et al, 2017 ) symptoms in youth. Nevertheless, findings regarding the directionality of these effects (positive vs. negative) are inconclusive.…”