Furthermore, since DA is involved in various aspects of motivational behaviors and psychotic states (Efimova et al., 2016; Howe et al., 2018), the abnormal behaviors of DAT-KO animals may have relevance also for endophenotypes of other psychiatric disorders such as schizophrenia, bipolar disorder, autism, mania, obsessive–compulsive disorder, and addiction disorders (Arime et al., 2012; Wong et al., 2012; Jones et al., 2015; Mereu et al., 2017; Weinstein et al., 2017; Chang et al., 2018; Cinque et al., 2018; Chao et al., 2020). The gene discussed is SLC6A3; the disease is bipolar disorder.