The co-release of 5-HT and glutamate has been evidenced by the presence of the vesicular glutamate transporter 3 (VGLUT3) in some 5-HT varicosities and the co-release of the 2 neurotransmitters has been proposed to play an important role in controlling the reward system (Liu et al., 2014; Sengupta et al., 2017) and anxiety-related behaviours (Amilhon et al., 2010; Sakae et al., 2019). The gene discussed is SLC17A8; the disease is Anxiety.