Victims of violence, accidents and threats are at risk for mental health problems. Lower coping self-efficacy and social support levels increase this risk. Although highly relevant, it is unknown if the coronavirus disease 2019 (COVID-19) pandemic amplifies these risks.

To examine if the prevalence, incidence and/or mean scores for post-traumatic stress disorder (PTSD), anxiety and depression symptoms, general mental health problems, coping self-efficacy, lack of emotional support and social acknowledgement are higher among adults victimised in the year after the COVID-19 outbreak compared with adults victimised in a similar period before the outbreak. Also, to compare symptoms, problems and support within non-victims during the same period.

Data was extracted from four surveys of the VICTIMS study (March 2018, 2019, 2020, 2021), based on a random sample of the Dutch population. Multivariate logistic regression analyses and mixed-effects models were used to examine differences between the two victim groups (2019: n = 421, 2021: n = 319) and non-victims (n = 3245).

Adults victimised after the outbreak more often had PTSD, anxiety and depression symptoms, general mental health problems and lower coping self-efficacy than those victimised before. They did not differ in lack of support and acknowledgement. Both victim groups differed from non-victims, where mental health problems and lack of support levels were much lower and almost stable.

The COVID-19 pandemic had a negative impact on the mental health and coping self-efficacy levels of victims, whereas mental health problems among non-victims remained virtually stable. Mental healthcare workers, general practitioners and victim services should take this impact into account.

How best to plan and provide psychosocial care following disasters remains keenly debated.

To develop evidence-informed post-disaster psychosocial management guidelines.

A three-round web-based Delphi process was conducted. One hundred and six experts rated the importance of statements generated from existing evidence using a one to nine scale. Participants reassessed their original scores in the light of others' responses in the subsequent rounds.

A total of 80 (72%) of 111 statements achieved consensus for inclusion. The statement ‘all responses should provide access to pharmacological assessment and management’ did not achieve consensus. The final guidelines recommend that every area has a multi-agency psychosocial care planning group, that responses provide general support, access to social, physical and psychological support and that specific mental health interventions are only provided if indicated by a comprehensive assessment. Trauma-focused cognitive–behavioural therapy (CBT) is recommended for acute stress disorder or acute post-traumatic stress disorder, with other treatments with an evidence base for chronic post-traumatic stress disorder being made available if trauma-focused CBT is not tolerated.

The Delphi process allowed a consensus to be achieved in an area where there are limitations to the current evidence.