“…For example, through sensitization, the reward system of someone who started smoking early in adolescence may develop in such a way that (s)he may be more vulnerable to other addictions including food addiction, and vice versa. In line with the gateway hypothesis, it has been proposed that sugar may act as a gateway 'substance', increasing the risk of becoming addicted to substances of abuse (Liester & Moore-Liester, 2015). Longitudinal studies are needed to further examine potential causal pathways.…”