NRG1 and schizophrenia: A limited number of gene mutations which increase risk for developing schizophrenia appear associated with cannabis abuse [e.g. Neuregulin 1 (NRG1) (Han et al. 2012) see also (Aukst Margetic et al. 2019)] and alcohol abuse [e.g. brain derived neurotrophic factor (Cheah et al. 2014; Zai et al. 2018), Neuregulin 1 (NRG1) (Vaht et al. 2017)]; however, no association has been shown for other genetic variants [e.g. cocaine and amphetamine regulated transcript with nicotine and alcohol abuse (Busto et al. 2010)].