Childhood trauma and altered response of retinal neurons as an early risk endophenotype of schizophrenia and mood disorder

Background

Exposure to childhood trauma may cause several alterations in brain structure and connectivity in adult patients having a major psychiatric disorder. Recent reports have shown that adult patients and young healthy offspring of patients carry similar abnormal retinal response. Because the retina and the brain have the same embryonic origin, the retina gives access to living neuronal tissue that may capture the early neurobiological effect of trauma.

Objective

Evaluate the association between exposure to childhood trauma and anomalies in cone (photopic) and rod (scotopic) responses assessed by electroretinography (ERG) in children and adolescents at familial risk (FHRs) of psychosis or mood disorders.

Methods

ERG recordings (n=194) undertaken on 134 offspring (M_age of 1st recording=15.7, 49% females) enrolled in our longitudinal study and born to a parent having DSM-IV schizophrenia, bipolar disorder or major depressive disorder were analyzed using repeated measures linear mixed models and applying multiple comparisons. The scotopic and photopic a- and b-wave latencies and amplitudes were recorded. Five types of childhood trauma were assessed prospectively and retrospectively in FHRs: physical abuse, sexual abuse, emotional abuse, neglect and witnessing domestic violence.

Results

None of the ERG scotopic or photopic parameters were associated with the global measure of exposure to trauma. However, when analyzing the specific effect of each type of trauma, data suggested that physical abuse in girls would be significantly associated with a prolonged scotopic a-wave latency (p=0.024, ES=0.28) and a trend of association was observed with a prolonged photopic b-wave latency (p=0.099, ES=0.27).

Conclusion

Our study did not suggest a substantial effect of childhood trauma on previously reported ERG anomalies in the cone and rod response in youth at familial risk of psychosis or mood disorder. Only one type of trauma i.e., physical violence toward the child, could have a specific effect on the cone and rod prolonged latencies in girls. Methodological limitations are discussed for consideration in interpreting the findings.