Childhood trauma may alter the structure of the brain in a way that makes clinical depression more likely to be severe and recurrent, according to new research published in The Lancet Psychiatry journal.
Some studies have shown a link between maltreatment and altered brain structure, while others have shown a link between maltreatment and major depressive disorder. The new study is the first to directly establish an association between maltreatment experiences, brain structural alterations and clinical course of depression.
For the study, researchers evaluated 110 patients, ages 18 to 60 years, who had been admitted to the hospital following a diagnosis of major depression.
Symptom severity was measured using questionnaires and interviews at two time points — at the time of initial recruitment (between 2010 and 2016) and at a two-year follow-up visit. All participants underwent a structural MRI scan at recruitment. The presence and level of childhood maltreatment was also asked via a questionnaire.
Results from MRI images suggest that both childhood maltreatment and recurring depression are associated with similar reductions in surface area of the brain’s insular cortex, a region believed to help regulate emotion and self-awareness.
The findings suggest that the observed reduction could make a future relapse more likely. Childhood maltreatment is one of the strongest risk factors for major depression.
“Our findings add further weight to the notion that patients with clinical depression who were mistreated as children are clinically distinct from non-maltreated patients with the same diagnosis,” said Dr. Nils Opel from the University of Münster, Germany, who led the research.
“Given the impact of the insular cortex on brain functions such as emotional awareness, it’s possible that the changes we saw make patients less responsive to conventional treatments. Future psychiatric research should therefore explore how our findings could be translated into special attention, care and treatment that could improve patient outcomes,” Opel said.
Patients were divided into two groups: those who did not experience any depressive episode in the two-year period (35 people, 17 men and 18 women) and those who experienced at least one additional depressive relapse (75 people, 35 men and 40 women).
Of the 75 patients in the relapse sample, 48 had experienced one additional episode, seven reported two episodes, and six experienced three episodes, while 14 had a remission period of less than two months and could therefore be regarded as having chronic depression. Childhood maltreatment was significantly associated with depression relapse.
Previous studies have only explored clinical state at the time of follow-up and did not consider clinical symptoms between assessments. For the new study, researchers assessed information on depressive symptoms over a full two-year period. Two years after they were recruited, all participants were invited to take part in a follow-up assessment in which symptoms within the full two-year period were assessed retrospectively.
A limitation of this work is that experiences of childhood maltreatment and depressive symptoms were asked about in retrospect and therefore could be subject to recall bias, the researchers said.
Source: The Lancet