In the current research, the highest prevalence of PTSD was found among earthquake survivors (58%). An earthquake with a magnitude of 6.3 on the Richter scale struck Bam city in Iran on December 27, 2003, that was one of the worst disasters of the century. It was disastrous and left more than 40,000 dead and about 30,000 injured people (
22,
39,
42,
52). In some studies on adults survived after a disaster, the PTSD prevalence was reported between 30 and 60% (
60-
62). The results of our study are in agreement with these results.
According to a study by Dai et al. while the reported incidence of PTSD in survivors recognized < 9 months after an earthquake was 28.76%, the incidence of PTSD was 19.48% for survivors evaluated > 9 months after the earthquake for PTSD (
63).
Sex and education level are also explanatory variables for the onset of PTSD after earthquakes. Women and those of low education level were more expected to develop PTSD, less expected to use strategies against distress, more susceptive to threats, and more expected to evaluate disasters more negatively (
63,
64).
In the current study, there were nine studies associated with wars that reported a prevalence of 47%. Furthermore, PTSD in war veterans was 46% and in the civilians was 30%. The Iran-Iraq War continued from September 1980 to August 1988, with air attacks and heavy artillery fire (
37,
53). Exposure to air attacks and massive artillery fire were devastating as they were irregular and people could not avoid or predict its devastating consequences (
65). In addition, based on a systematic review in Lebanon during several wars between 1975 and 2006, reported PTSD rates were between 3.7 and 35% (
65). According to the mentioned studies, PTSD rates have been increased with time, which is in line with our results.
The rate of PTSD in US military veterans following the Vietnam War varied between 2 and 17% (
66). The PTSD prevalence in Australian Vietnam veterans was estimated at 21% in the lifetime and 12% at present (
67).
Another study reported that the PTSD rate was 21.6% in the grapes of Wrath War in 1996 and ranged from 15.4 to 35.0% in July 2006 (
65). Some of these variations may be associated with the approval of various measures based on various DSM diagnostic measures for PTSD. The gap between exposure to war violence and data gathering, exposure to different types of war events, and the severity of such exposures can be considered as other factors.
In our study, the prevalence of job-related PTSD was 30%. Our literature review showed that the prevalence of PTSD in rescue workers, in general, ranged from 14% to 36%. In addition, we observed higher PTSD rates in studies carried out among ambulance workers. This is consistent with other studies (
68). Several studies have confirmed that rescue operations have a higher risk of PTSD incidence (
69,
70). These observations confirm that rescue workers comprise a susceptible group for the incidence of PTSD (
71,
72).
According to another study, various occupational groups had different rates of risks for PTSD incidence (
68,
73). However, the current study confirms the results of previous studies that ambulance workers have the highest PTSD rates among the occupational population of rescuers (
68). The very high rate may be because ambulance workers are exposed to higher anxiety at work compared to other rescue groups (
74). A study reported that rescuers from Asia, at least partially, have a higher PTSD prevalence compared to the European counterparts (
68).
In our study, seven studies investigated PTSD following childbirth and the prevalence of PTSD in these studies was 25%. PTSD after childbirth was first defined by Bydlowski and Raoul-Duval (
75) with painful experiences during labor leading to tocophobia and recurrence of tension, nightmares, and flashbacks towards the end of the next pregnancy. Numerous authors afterward suggested that PTSD may occur after distressing labor or delivery (
76,
77).
A difficult or traumatic birth may be an important stressor, similar to the known stressors such as violence or war causing PTSD symptoms. The stressful experience is often a pain but loss of control and fear of death can also be a kind of pain (
78). Studies accomplished in the USA, Sweden, Germany, the UK, Australia, and Canada have reported a prevalence ranging from 0.9 to 5.6%. There is a meaningful relationship between the creation of PTSD and the control source, the level of social support, and the previous experience of injuries in these studies (
75).
In the current study, two studies were related to burn cases, and the reported prevalence was 40%. In other studies, the pain was also associated with PTSD incidence in injured patients including burn patients (
79,
80). Moreover, in our study, two studies were related to accidents with the prevalence of 11% and two studies were related to rape victims with the prevalence of 74%.
Post-traumatic stress disorder in events that cause significant damage should be checked as this disorder develops especially two months after the accident. Driving accidents are responsible for more than 50% of deaths worldwide at the age of 15 - 44 (
81). In Iran, driving accidents are the second leading cause of death (
82). In a systematic review by Olofsson et al. which examined 12 studies on post-traumatic stress disaster related to accidents, 29% of post-traumatic stress was reported to reduce to 13% after 3 - 6 months of injury (
83).
Violence and sexual harassment are of important issues that are considered in many perspectives such as psychological, social, cultural, demographic, political, and health viewpoints, and are observed in all countries and all social, cultural, and religious groups as they affect thousands of women every year. However, it is believed that over 80% of sexual harassment cases are not reported and the actual incidence is higher than what is now reflected (
21). The results of a study by Zinzow et al. showed about 30% to 50% of victims developed PTSD after the onset of PTSD symptoms (
84). In addition, in a study by Alynch, the prevalence of PTSD was reported to follow completely different rates. In victims with less experience of sexual harassment, this rate was 4%, and in those with a higher degree of sexual harassment, it was 80% (
85).
In this study, our purpose was to carry out a systematic review of the evidence regarding PTSD following the war and disasters that might recommend a direction for research and intervention. Arguably, the available information is sufficient to suggest plausible ranges of PTSD prevalence that can be expected after war and disasters, within the particular exposure groups.
The current study had some limitations. We opted to include a wide range of PTSD studies, with differences in methodologies. In addition, this meta-analysis only included cross-sectional studies, making to understand the temporal order of correlations between explanatory variables and PTSD. This study has several strengths including the fact that this is the first systematic review of PTSD prevalence in the Iranian population.