Major migratory crises resulting from forced displacement have increased dramatically in the last few years all over the world, bringing new challenges for Western general and mental health services. For years, research has been focused on pre-migration and per-migration risk factors to try to explain the high prevalence of psychiatric disorders among asylum seekers, even years after resettlement. Recently, more attention has been given to post-migration risk factors, since different studies have underlined the impact of post-migration living difficulties on the prevalence of psychiatric disorders. Among these factors we can mention uncertain administrative processes, separation from the family remaining in the home country, housing conditions, access to professional training or activity, and social isolation. Some authors have mentioned specific factors that concern some particularly vulnerable sub-groups, such as women (who mostly migrate alone or with children), and subjects under eighteen years of age (especially those who migrate alone) who require specific attention.
Concerning psychopathology research, studies have mostly focused on post- traumatic stress disorder (PTSD) and major depressive disorder (MDD). However, prevalence rates reported are very heterogeneous because of major methodological variations and different access to transculturally-validated questionnaires and the use of self-administered questionnaires. In addition, personality, addictive and psychotic disorders appear to have surprisingly low prevalence rates, so further studies are necessary to obtain a better global perspective on the complexity of diagnostic evaluation in this population. The recent concept of "complex post-traumatic stress syndrome" provides new insight into post-traumatic symptoms.
Barriers to access to treatment for this population are a real challenge for modern Western public psychiatry. They are of different kinds, some of them are linked to personal factors, such as self-stigma, lack of trust or lack of information about mental disorders. Others result from the organisation of medical services at local level. Several strategies should be considered in order to provide better access to mental health services, taking into account the origin, gender and age of each sub-group concerned.
From the point of view of research, more longitudinal studies on less well explored psychiatric disorders and resilience factors are needed.
