Selection criteria

Animal studies, non-original and unpublished research papers were excluded as well as studies not reporting any type of neuroimaging outcome. Also excluded were studies that did not involve a direct comparison (either in primary or secondary analyses) of the outcome variables for exposed and unexposed individuals to either emotional, physical, or sexual childhood maltreatment while controlling for the effects of other subtypes either by excluding individuals with a history of these other types or by statistical correction. Papers investigating multiple subtypes were included provided they looked into the specific effects of each of these subtypes while controlling for the others. Childhood trauma subtypes were defined according to the criteria of the Fourth National Incidence Study (NIS-4; Table ​Table1)1) (27) in which study maltreatment events are only considered childhood abuse if they cause actual harm or pose a serious risk of harm to a child up to 18 years of age and occur within the household setting (i.e., perpetrated by a family member or caregiver). One study on peer verbal abuse (28) was accordingly excluded (no household context).

NIS-4 criteria for childhood trauma subtypes.

We defined maltreatment as abuse, neglect or both of a particular type, where for instance emotional maltreatment can encompass both emotional abuse and neglect. Other types of early-life adversities such as loss of a parent, institutionalization, and poverty were not specifically addressed in our search because these dire circumstances do not fit our definition of maltreatment, while they also constitute a very heterogeneous group of life events that are difficult to assess in the light of the lack of objective measuring scales and the fact that they are not consistently controlled for in childhood trauma research. To include as many papers as possible, no a priori selection was made based on the language of the article, with none of the papers screened having to be excluded on account of a language barrier.