“…If environmental stress exposure is linked to illness onset, especially during key developmental periods (Walker et al, 2001(Walker et al, , 2010, then central nervous system (CNS) HPA-axis dysfunction should be present in schizophrenia. In support of this HPA-axis dysfunction, for over 30 years, researchers have identified high concentrations of cortisol present in schizophrenia samples (Coppen et al, 1983;Tandon et al, 1991;Walker et al, 2013). These findings, coupled with documented evidence of diminished hippocampal volume, further highlight the mediating role of the HPAaxis functioning between environmental stressors and psychiatric illness (Stansbury and Gunnar, 1994;Walker and Diforio, 1997).…”