Lowe, S. and Galea, S. (2017). The Mental Health Consequences of Mass Shootings. Trauma, Violence, and Abuse. 18(1): 62-82.
The authors conducted a literature review and found several variables associated with negative mental health effects related to mass shooting incidents: "demographic and pre-incident characteristics (e.g., female gender and pre-incident psychological symptoms), event exposure (e.g., greater proximity to the attack and acquaintance with the deceased), and fewer psychosocial resources (e.g., emotion regulation difficulties and lower social support)." They emphasize the need for more research that can inform preparedness and post-incident interventions.