Many drugs acting on 5‐HT receptors, such as 5‐HT1A agonists, 5‐HT1A/B agonists, 5‐HT2A antagonists or 5‐HT transporter (SERT) inhibitors have been tested and proven to be effective in reducing l‐DOPA‐induced dyskinesia in animal models (Bibbiani, Oh, & Chase, 2001; Bishop et al., 2012; Grégoire et al., 2009; Hamadjida et al., 2018; Lindgren, Andersson, Lagerkvist, Nissbrandt, & Cenci, 2010). Here, SLC6A4 is linked to drug-induced dyskinesia.