There are also contradictory results regarding whether physical exercise interventions enhance plasma brain-derived neurotrophic factor (BDNF) in people with schizophrenia (Ikai et al., 2014; Kim et al., 2014; Kimhy et al., 2015; Firth et al., 2017b), which is suggested to be the underlying factor for the beneficial changes in brain structure and functional connectivity gained through exercise interventions for people with schizophrenia. The gene discussed is BDNF; the disease is schizophrenia.