BackgroundMental health problems among trafficked persons could be the result of concomitantly interwoven effects of various factors. Analyzing the networked relationships concurrently could be a more substantive approach to better understand the role of risk factors in this population. This study aimed to assess the magnitude of mental health symptoms as well as the association among socio-demographic, trafficking related exposure variables, and mental health problems of Ethiopian returnees from trafficking.MethodsA sample of 1387 returnees who were trafficked via three major human trafficking corridors of Ethiopia were selected consecutively. Data related to socio-economic, trafficking exposure variables, and symptoms of mental illness were collected in personal interviews. Anxiety was measured with a brief measure for generalized anxiety disorder (GAD-7), depression with a patient health questionnaire (PHQ-9), and PTSD with post-traumatic checklist (PCL-C). Generalized structural equation modeling was employed to estimate the relationships among exogenous, mediating, and endogenous variables simultaneously.ResultsThe prevalence of symptoms of anxiety was estimated at 51.9% (95% CI 49.3–54.6%); PTSD was estimated at 34.5% (95% CI 32.1–37.1%) and depression at 58.3% (95% CI 55.6–60.9%). Restricted freedom of movement had a direct positive effect on anxiety (β = 1.24, 95% CI 0.97–1.51), depression (β = 0.94, 95% CI 0.71–1.17) and PTSD (13.00, 95% CI 11.23–14.77). Violence experienced during the trafficking period was a mediator variable and significantly associated with anxiety (β = 0.46; 95% CI 0.26–0.66) and PTSD (β = 4.00; 95% CI 2.06–5.94). History of detention had a positive total effect on GAD (total β = 1.380, 95% CI 1.074–1.687) and PTSD (total β = 15.63, 95% CI 13.708–17.545), and direct positive effect on depression (β = 0.89, 95% CI 0.65–1.13).ConclusionEthiopian trafficked persons were highly likely to return with increased levels of mental health symptoms, namely anxiety, depression, and PTSD. Socio-economic and trafficking related exposures mediated by violence were factors affecting mental health symptoms. Thus, in addition to economic re-integrations of victims, strategies should be designed and implemented to address the prevalent mental health problems.Electronic supplementary materialThe online version of this article (10.1186/s13033-018-0241-z) contains supplementary material, which is available to authorized users.