HMN 2026: How Childhood trauma is tied to tough depression cases

People who have experienced adverse childhood experiences are at increased risk of developing depression later in life that is difficult to treat. This is shown in a new twin study from Karolinska Institutet based on Swedish twin data, published in the journal JAMA Network Open.

Depression is one of the most common mental disorders, but not everyone responds to standard treatments. In some cases, the condition develops into a treatment?resistant form. In the new study, researchers investigated whether adverse childhood experiences, such as neglect or abuse, are associated with an increased risk of treatment?resistant depression.

The researchers analyzed data from more than 21,000 Swedish twins, of whom around 17,800 were included in the main analysis. Questionnaire data on childhood experiences were combined with information on depression diagnosis and medications from national health registers. The results show that the risk of treatment?resistant depression increased with each adverse childhood experience, even when comparing twins who grew up in the same family.

Higher risk after multiple negative experiences

Among individuals who reported three or more adverse childhood experiences, around 5% had treatment?resistant depression, compared with 0.7% among those without such experiences.

“Knowledge of difficult childhood experiences may be important for the early identification of patients at increased risk of treatment-resistant depression and could help clinicians better understand individual patients when they assess them,” says first author Ying Xiong, postdoctoral researcher at the Department of Medical Epidemiology and Biostatistics, Karolinska Institutet.

The researchers emphasize that the findings provide support for a possible causal link. However, the study is observational, and further studies are needed to confirm the results before firm conclusions can be drawn.

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