Self-harm and suicidal behavior range among the most prominent public health concerns in children and adolescents. The term “self-harm” commonly includes both direct and indirect self-damage with and without suicidal intent; whereas, the term “self-injury” refers to direct self-damage only but again regardless of its intent. Self-harm has a mean prevalence of 18% worldwide [1], and a study investigating the life-time prevalence of self-injury among European adolescents found rates up to 39% [2]. Suicidal ideation and suicide attempts have been reported in about 12% and 4% of adolescents, respectively [3]. The particular importance of adolescent self-harm is underlined by the fact that it is often associated with suicidal ideation and behavior, and that it is one of the strongest risk factors predicting suicidal behavior [4] and death by suicide later in life [5].

Research trying to better understand the developmental pathways into self-harm and suicidal behavior is highly warranted. One of the risk factors that has often been reported for adolescent self-harm and suicidal behavior is childhood maltreatment [6, 7]. However, the evidence of the overall strong association between childhood adversity and these outcomes is limited by the following factors:

  1. 1.

    Very few prospective studies have been conducted and most data are derived from retrospective assessment of childhood maltreatment, which may be prone to substantial recall bias, particularly since individuals engaging in self-harm and suicidal behavior commonly suffer from mental health problems that may have an impact on their current perception of childhood experiences.

  2. 2.

    Most data are derived from adult samples and to a substantially lesser extent from adolescent samples with a mean age commonly > 14 years. However, given that self-harm (and also suicidal ideation and behavior) often occurs in early adolescence [8], the period of mid-to-late childhood and early adolescence is certainly understudied.

  3. 3.

    The pathways from early adversity to self-harm and suicidal behavior are relatively unclear, and directionality or even causality has yet to be established unequivocally.

The original article of Paul and Ortin (2019) in this issue has overcome some of the serious limitations. The authors investigated self-harm behavior and suicidal ideation in children at the age of 9 years; childhood abuse and neglect had already been investigated at the children’s age of 3 years within this longitudinal cohort, which adhered to a strictly prospective design. Most interestingly, they investigated potential pathways from early maltreatment to self-harm via different types of psychopathology. While neglect predicted both suicidal ideation and self-harm via internalizing psychopathology, physical and psychological abuse only predicted self-harm via more externalizing mental health problems [9]. Thus, the authors found evidence for specific pathways linking particular types of maltreatment with self-harm and suicidal ideation later in childhood.

The respective results may not only be relevant for the development of particular internalizing versus externalizing disorders, but they also fit those subjects commonly suffering from complex childhood adversity including various types of maltreatment. These individuals, who we often see as subjects suffering from borderline personality disorder [10] or complex posttraumatic stress disorder [11], usually show a characteristic combination of both internalizing and externalizing psychopathology.

There are also some limitations to the study of Paul and Ortin (2019), e.g., the assessment of self-harm, which was not divided into non-suicidal self-injury and suicidal behavior (as nowadays suggested within the DSM-5), was limited; in addition, all assessments were based on self-report only. However, the CBCL has recently been shown to have good validity in the assessment of self-harm and suicidal behavior [12]. Overall, this study represents an important step in the right direction.

The results of the article add to the ongoing discussion of different types and differential effects of childhood maltreatment. Negative childhood experiences can be quite heterogeneous; thus, it is quite plausible that the short- and long-lasting effects may differ substantially. There is some evidence that this is true for both biological and psychopathological consequences [13]. However, research on the differential effects of different types of childhood adversity has also been limited due to the substantial overlap of these different types. This overlap may require larger samples to finally disentangle particular subgroups of maltreatment, e.g., those with pure neglect and those with abuse only. Of course, future research will also need to address the role of genes and of parents’ personality or psychopathology in large-scale and longitudinal studies. One might argue that different parents might be prone to different types of maltreatment based on their genetic predisposition, their upbringing, and/or their own personality and psychopathological profiles. For example, depressed parents may rather neglect than abuse their offspring. It seems plausible that we see more internalizing symptoms among their children, but is this caused by the type of maltreatment or rather by the shared genetic risk or the parental psychopathology itself? In turn, parents with externalizing psychopathology may tend to abuse rather than neglect their children; but again, having children with externalizing psychopathology might not only be a consequence of the type of maltreatment. There are still more questions than answers on this topic, but this is certainly a very important and interesting area of research for the future.

Overall, the article from Paul and Ortin in this issue suggests that childhood maltreatment is an important risk factor for self-harm and suicidal behavior in later life, and that different psychopathological pathways may mediate this association depending on the type of maltreatment experienced. More research on such differential pathways may facilitate a more tailored prevention and early intervention for children and adolescents who are at-risk of self-harm and suicidal behavior in the future.