A Systematic Review and Meta-Analysis of Longitudinal Studies on Posttraumatic Stress Disorders in Refugees and Asylum Seekers

Posttraumatic stress disorder (PTSD) is among the common mental disorders in refugees and asylum seekers; however, it is unclear if population prevalence declines or persists after resettlement. Therefore, this study aimed to identify longitudinal studies reporting PTSD among refugees and asylum seekers in upper-middle and high-income countries and to conduct a meta-analysis to map the trajectory of PTSD prevalence over time in order to inform policymakers. Seven electronic databases were searched for relevant prospective longitudinal studies. The Joanna Briggs Institute (JBI) scale was used to assess the quality of studies, and we excluded studies with a high risk of bias leaving 21 studies: 13 with moderate and 8 with a low risk of bias. The total follow-up period ranged from 1 to 7 years. Random effects meta-analysis pooling all studies suggested a baseline prevalence of 17.65% in the immediate period after resettlement (up to 1 year after arrival) and a trend for decreasing prevalence to 11.64% over time. However, studies with over 6 years of follow-up indicated a higher longitudinal prevalence of 13-17%, and in the low-risk-of-bias study subgroup, the prevalence did not decrease (ranging between 27.54 and 30.10%), which raises the possibility that PTSD prevalence may not substantially decrease in the first 6 years after resettlement. The finding that studies with a low risk of bias reported a larger prevalence of PTSD persisting over time highlights the importance of conducting high-quality longitudinal studies to inform policy. Appropriate long-term interventions are needed to decrease the impact of traumatic events on the mental health of refugees and asylum seekers.