A Closer Look on Prodromal Psychotic States in Immigrants and Ethnic Groups: A Comprehensive Literature Review.
Objectives: To conduct a literature review on the evidence pertaining to prodromal psychotic states, ultrahigh risk for psychosis (UHR), and variation in ethnic groups and immigrants with a focus on the interplay gene-environment towards psychotic states.
Methods: A systematic literature search was conducted in Pubmed, Google scholar on studies evaluating immigrants and ethnic minorities at risk for mental states- psychosis (ARMS) or UHR. We used the following key words, “prodromal psychotic states”, “UHR”, “at risk for mental states”, followed by “immigrants and ethnic groups”. We elected to include mainly prospective-longitudinal studies, systematic reviews and meta- analyses as well as those with a clinical study design. Studies that addressed prevalence and incidence rates of schizophrenia were excluded due to the focus of our review.
Results: Initially 36 studies were retrieved of which 18 studies meet our inclusion criteria published from 2003 to 2016.We found that only two studies had a meta-analytic design that addressed the risk for psychosis among second generation immigrants, first generation immigrants and non- immigrants and the transition to psychosis in UHR. Most of the studies evaluated the prevalence rates of transition to psychosis in population at high risk proposing predictors with good specificity and sensitivity. Two of the studies included large longitudinal studies (EPOS; NAPLS) assessing transition to psychosis. One study assessed the rate of psychotic disorders on socially deprived environments at the time of onset. Social adversity was evaluated in 3 studies by analyzing perceived discrimination and migrant status, childhood traumas and ethnic identity in the context of racial environments. Interestingly 2 studies evaluated neighborhood and spatial distribution as ethnic identity features and transition towards psychosis. Predictors of transition to psychosis in UHR patients were: schizotypal personality disorder, lower level of functioning at baseline, duration of symptoms, negative symptoms, though content disorders. Ethnic minorities overall showed worse outcome with a predominance of negative symptoms. UHR criteria demonstrated to have a good positive predictive validity in transition to psychosis.
Conclusion: The evidence suggests that ethnicity plays an important role in the transition to psychosis by demonstrating an effect even on second generation immigrants supporting genetic and environmental factors. Environmental factors, such as socially deprived neighbourhoods showed a higher risk for psychotic disorders as also linking childhood traumas with positive symptoms. In addition, level of social deprivation at birth but not during lifetime was associated with a higher risk for psychosis. Nevertheless, more evidence is needed from studies with a longitudinal designs to ascertain the relationship of ethnicity and migration with the complexity of psychotic disorders to achieve better intervention strategies to ameliorate those who are vulnerable to psychosis.