STS and Anxiety: Work in male rodents has shown that deletion of the Sts gene, or acute inhibition of the STS enzyme, is associated with numerous behavioural phenotypes including inattention, anxiety-related behaviours, aggression, perseveration, learning and enhanced memory, and behavioural inhibition (Johnson et al. 2000; Nicolas et al. 2001; Davies et al. 2009; Trent et al. 2012b; Babalola et al. 2012; Trent et al. 2013; Davies et al. 2014); these phenotypes may be partially related to serotonergic and cholinergic differences in the hippocampus (Trent et al. 2012a; Trent et al. 2013; Yue et al. 2016).