Methadone does not alter key parameters of adult hippocampal neurogenesis in the heroin-naïve rat

► The effect of methadone on adult hippocampal neurogenesis was studied in rats. ► Methadone decreased weight gain and exploratory locomotor activity. ► However, methadone did not alter key aspects of adult hippocampal neurogenesis. ► Methadone appears distinct from other opiates in having no effect on neurogenesis. ► Disrupted neurogenesis may not always be associated with cognitive deficits.