Schizophrenia and Childhood Adversity

To the Editor: In his editorial, published in the January 2010 issue of the Journal, John H. Gilmore, M.D. (1), argues for a developmental perspective in relation to schizophrenia. However, it is perhaps no longer accurate to argue that "most studies have focused on pre- and perinatal environmental risk factors" (1, pp. 8, 9). Recently, researchers have found a range of adverse events in childhood to be significant risk factors for developing psychotic symptoms and/or being diagnosed with schizophrenia, even after controlling for family history of psychosis or schizophrenia in some cases. These adverse events include early loss of a parent; parental poverty; bullying; witnessing parental violence; emotional, sexual, or physical abuse; physical or emotional neglect; and insecure attachment (2, 3).

These findings support the editorial's call for "a new concentration of efforts on childhood brain development" (1, p. 9). The Traumagenic Neurodevelopmental model (4) is based on findings that differences in the brains of many adults diagnosed with schizophrenia are also found in children who have been severely traumatized, especially in the first years of life. These include overactivity of the hypothalamic-pituitary-adrenal axis; dopamine, norepinephrine, and serotonin abnormalities; hippocampal damage; cerebral atrophy; ventricular enlargement; and reversed cerebral asymmetry. Thus, the heightened sensitivity to stress evidenced by dysregulation of the brain's stress regulation mechanisms is not necessarily inherited. It can be caused by childhood trauma.

Gene-environment interactions will be best understood in terms of new knowledge about how epigenetic processes turn gene transcription on and off through mechanisms that are highly influenced by socioenvironmental experiences (3). It will be important to integrate these epigenetic processes, especially those involving the stress regulating functions of the hypothalamic-pituitary-adrenal axis, with research about the psychological mechanisms (cognitive distortions, attachment, dissociation, etc.) by which specific types of childhood trauma can lead to specific types of psychotic experiences (2, 3).

While it can be tempting to ignore childhood adversity, out of fear of being accused of family-blaming, many childhood adversities occur outside the family and those that occur within families tend to be intergenerational and are therefore areas in which many families need assistance. Indeed, we were pleased to see the implications for prevention mentioned in the editorial. We also feel that it is important to note that one environmental enrichment program for children ages 3 to 5 years reduced schizotypal personality scores in adulthood (5).