upsetting material. Professors were encouraged to alert students of such material and allow them to skip classes that could make them feel uncomfortable. Limited value for general use Although the subject has generated political controversy, research suggests that trigger warnings are neither harmful nor especially helpful. Among people without traumatic experiences, "trigger warnings did not affect anxiety responses to potentially distressing material in general." Studies disagree on whether trigger warning cause transient increases in anxiety in those without traumatic experiences. For participants who self-reported a posttraumatic stress disorder (PTSD) diagnosis, or for participants who qualified for probable PTSD, trigger warnings had little statistically significant effect. Effect sizes on feelings of avoidance, decreased resilience, or other negative outcomes have been "trivial" in controlled research environments. While trigger warnings have garnered significant debate, few studies have investigated how students typically respond to potentially triggering material. In a 2021 study, 355 undergraduate students from four universities read a passage describing incidents of both physical and sexual assault. Longitudinal measures of subjective distress, PTSD symptoms, and emotional reactivity were taken. Greater than 96% of participants read the triggering passage even when given a non-triggering alternative to read. Of those who read the triggering passage, those with triggering traumas did not report more distress although those with higher PTSD scores did. Two weeks later, those with trigger traumas and/or PTSD did not report an increase in trauma symptoms as a result of reading the triggering passage. Students with relevant traumas do not avoid triggering material and the effects appear to be brief. Students with PTSD do not report an exacerbation of symptoms two weeks later as a function of reading the passage. History Trauma triggers have been recognized by medical professionals since the 19th century. See also Acute stress reaction Content rating Emotional dysregulation Hypervigilance Motion Picture Association of America film rating system Parental Advisory Repressed memory Survivor guilt Thematic elements References External links Treatment of mental disorders