The potential relationships between traumatic experiences and the onset and course of major mood disorders have always been controversial. Some experiences, most notably physical or sexual abuse, as well as substantive bullying in childhood, are clearly recognised as major risk factors for a range of mental disorders, as well as a range of linked phenomena including self-harm and suicidal behaviours (McKay et al., 2021; Zatti et al., 2017). There is considerable interest and ongoing research into how these adverse experiences come to be ‘encoded’ via neurobiological or genetic mechanisms that then transmit those effects into later-onset major mental disorders, substance misuse or other self-harming behaviours (Maddox et al., 2019).