The results of a study published in European Neuropsychopharmacology indicate that patients with type I bipolar disorder experienced significantly more childhood abuse, and had lower white matter integrity overall.
Several relationships have been identified between early-life trauma, bipolar disorder, and white matter integrity. Childhood abuse is a major risk factor for later bipolar disorder, and may compromise white matter integrity regardless of whether an individual who has experienced abuse ultimately receives a diagnosis.
In this study, the investigators identified 251 patients with type I bipolar disorder and 163 controls using data from the Dutch Bipolar Cohort. All participants were age >18 with at least 3 Dutch grandparents and no head trauma or serious neurologic disorder. To qualify as a control, participants could not have any first- or second-degree relatives with bipolar disorder. All participants completed the Mini-International Neuropsychiatric Interview, and early-life adversity was assessed using the Childhood Trauma Questionnaire.
Participants underwent diffusion tensor imaging to determine their white matter integrity, expressed as fractional anisotropy, a scalar value that describes fiber integrity based on various properties of white matter microstructure. The investigators found a significant relationship between abuse, especially types of physical abuse, and widespread white matter integrity in patients with type I bipolar disorder. White matter integrity was also significantly lower in patients with bipolar disorder regardless of history of abuse.
On the other hand, there appeared to be no association between childhood neglect and white matter integrity in patients with bipolar disorder. These findings are in line with previous research, which has suggested that abuse and neglect in childhood have different effects on the brain.
While the study is the largest to date investigating abuse and white matter integrity, its cross-sectional design and the use of the self-report Childhood Trauma Questionnaire limit the interpretability of its findings. In addition to establishing causation, the researchers hope that future investigations can identify larger pools of controls who were healthy in spite of childhood abuse.
Stevelink R, Abramovic L, Verkooijen S, et al. Childhood abuse and white matter integrity in bipolar disorder patients and healthy controls [published online June 2, 2018]. European Neuropsychopharmacology. https://doi.org/10.1016/j.euroneuro.2018.05.003