We aimed to clarify the characteristics of foreign residents visiting psychiatric departments in the Keihin region, which is the largest metropolitan area of Japan. The results revealed that the proportion of foreign patients was 1.4% among the total patients, that most of the foreign residents were from Asian countries, and that their mean age was 45.8 years. We also revealed that there were about twice as many female patients as there were male patients, and that neurotic disorders (ICD code: F4) were the most common diagnosis. Foreign patients who could not speak Japanese received interpretation through a family member or friend more frequently than through a trained medical interpreter.
Nationality/region
The percentage of foreign patients seeking psychiatric treatment (1.4%) was relatively low, compared with the percentage of foreign residents living in the Keihin region (4.4%) [7, 8]. This result may indicate that foreign residents in Japan are less likely to contact adequate services for mental health problems, compared with majority populations, similar to the results of other studies published outside of Japan [13, 29].
In 2019, there were 2.82 million foreign residents living in Japan, including 0.79 million Chinese, 0.45 million Koreans, 0.37 million Vietnamese, 0.28 million Filipinos, and 0.21 million Brazilians [7]. The distribution of nationalities in the present study was similar to that for Japan overall (Table 1). When looking at changes in foreign populations over the past 10 years in Japan, the numbers of Chinese and Filipinos have been increasing moderately, while the number of Koreans has been gradually decreasing. Notably, the number of Vietnamese is growing rapidly, increasing from 41,000 in 2009 to 370,000 in 2019 [7]. Of the 110,000 foreign nationals living in the Keihin region, 12,000 are Vietnamese, and the Keihin region is known to be an area where the number of Vietnamese foreign residents is increasing rapidly [7]. Given that this increase in Vietnamese people living in the Keihin region is relatively new, the low proportion of Vietnamese patients in the present study may suggest that a short duration of residing in Japan as an ethnic group may be a barrier to appropriate consultation [28, 38]. Furthermore, many Vietnamese individuals living in Japan are young technical intern trainees, and this characteristic seems to be related to a relatively short visit [4].
Distribution of foreign patients according to age
The age distribution of the foreign resident population in Japan peaks at individuals in their twenties, which corresponds to an age of increased susceptibility to mental illnesses (Figure 1) [7, 39, 40]. Since immigrants are known to have greater mental vulnerability than the majority populations in a community [10, 15, 16, 23], a number of foreign residents in Japan are thought to be at a high risk of mental illness. Regarding residence status, the number of foreign students and technical intern trainees is rapidly increasing, accounting for 24% of the total for foreign residents in 2019 [7]. This means that the inflow of foreign residents in their youth or early adulthood has increased in Japan. Mental health problems in young adults negatively impact academic, professional, and social activities [41]. While the distribution of psychiatric patients by age generally follows the distribution of the total population by age in Japan [37, 42], the age distribution of foreign residents who visited psychiatric department at three hospitals was dissociated from the age distribution of foreign residents in Japan (Figure 1) [7]. This suggests that young foreign residents with a relatively high risk for mental illness are not accessing appropriate services. The lack of access among young foreign residents may also be explained by a short-period of residence in Japan [13, 28], although further investigations are needed. On the other hand, the fact that middle-aged patients were prominent in the present study may be explained by the association of these individuals with long-term residents who may face fewer language barriers [13, 28]. A previous report showed that a deficiency in social connections in post-migratory surroundings can lead to isolation and distress [38]. Therefore, there is a need to develop community-based integrated mental health services that include foreign residents [13, 40, 43].
Sex ratio of foreign patients
The sex ratio of psychiatric patients in Japan was almost even in a national survey [37]. However, the number of male patients in the present study was disproportionally low, although the sex ratio of foreign residents living in Japan is also almost even (males: 49.0%; females: 51.0%) [7]. This difference can be explained by a previous finding that male immigrants are known to be less likely to use services than female immigrants [13, 38]. Meanwhile, a systematic review on immigrants to Japan suggested that female immigrants faced barriers to mental well-being; however, most of the reviewed studies investigated specific samples, such as students [28].
Pathways to hospital visitation and language problems
About forty percent of the subjects visited the psychiatric departments voluntarily by themselves or at the recommendation of a family member or friend, and almost the same proportion of subjects were introduced by other hospitals or other departments in the same hospital. The result that the proportion of subjects introduced by other hospitals or departments was comparable with the proportion of subjects visiting on a voluntary basis is consistent with previous studies, indicating that immigrants may have difficulty seeking psychiatric medical consultations directly because of language barriers, a lack of encouragement from others, or stigmas towards mental illness [28, 32, 44].
As for involuntary visits, the results that 3.9% of the patients visited because of suicide attempts and 2.9% visited at the request of the police also seem to be worth noting. Immigrants are reportedly more likely to experience suicidal ideation and to have received fewer services before a suicide [23, 30]. The present results also suggest that their mental health problems may not have been properly treated, resulting in suicide attempts. Regarding the subjects who visited at the request of the police, most of their diagnoses were schizophrenia. Further studies that examine the duration of untreated psychosis (DUP) among foreign nationals in Japan, who have difficulty accessing social support and resources, as well as among the total population in Japan are anticipated [45].
Regarding medical interpretation, a number of studies have reported that the quality of care in patients who did not speak a host country’s language was compromised when interpreters were not available, whereas trained professional interpreters have positive effects on patient satisfaction, quality of care, and patient outcomes [46]. A systematic review on immigrants in Japan suggested two common barriers: troubles in communicating in Japanese, and a lack of social support [28]. About one fourth of the subjects could not speak Japanese, and these subjects required interpretation by a family member, not a trained medical interpreter (Table 1). Professional medical interpreters are preferred because family interpreters can unknowingly convey technical errors because of a lack of expert knowledge. Inadequate interpretation may lead to serious consequences for patients with mental problems [46]. Language barriers are known to be associated with poor mental health, a low use of appropriate services, and an increase in suicide behavior [13, 28, 47]. The present study revealed that the use of medical interpreters remains rare, and this limitation may impede the health conditions, especially the mental health conditions, of foreign residents.
Diagnosis
Neurotic, stress-related and somatoform disorders (ICD code: F4), which have a significant impact on social functioning [48], were the most common diagnoses (Table 1). The proportion of F4 diagnoses in this study was higher than that for Japanese national data (Figure 2). This result suggests that acculturation stress in daily living surrounded by different cultures and habits affects foreign residents, as previous studies have reported [10, 17]. The proportion of schizophrenia, schizotypal and delusional disorders (ICD code: F2), which was the second most common diagnosis in this study, was almost equal to that for Japanese national data (Figure 2). Immigration is reportedly a risk factor for the onset of psychosis [15]. The proportion of F2 diagnoses in this study would likely be higher if young foreign residents visited hospitals when needed. Mood disorder (ICD code: F3) was the third most common diagnosis, and the proportion of F3 diagnoses in this study was relatively smaller than that for Japanese national data (Figure 2). This result may reflect that immigrants are not at risk for mood disorders, which is consistent with a meta-analysis that did not show a significant increase in mood disorders associated with immigration [22].
Immigrants are known to be at risk for substance use for reasons that include acculturative stress, social and economic disparity, and co-morbid mental health disorders. Some reviews have indicated that immigrants, even children and young people, have a high risk of substance use, including drug injection [20, 24, 49]. Actually, the proportion of mental and behavioral disorders arising from psychoactive substance use (ICD code: F1) in this study was higher than that for Japanese national data (Figure 2).
Treatment outcome
In terms of treatment continuation, a survey conducted by the World Health Organization showed that the discontinuation rate for psychiatric treatments was about 20% [50]. In a Canadian study of first-episode psychosis, disengagement rates did not differ significantly between immigrant and non-immigrant groups (23% vs. 25%) [51]. Although it remains uncertain whether immigrants are more likely to discontinue treatment than the general population, the discontinuation rate in the present study (32.2%) appeared to be fairly high (Table 1).
Limitations
Some limitations should be noted in this study. This was a retrospective study based on medical records, and the targeted period of the record investigation was three years. Furthermore, the study sample was from data obtained at only three hospitals in the Keihin region. However, these hospitals are responsible for areal core hospital function and are the largest hospitals in each district of the Keihin region. Therefore, the findings in this study are thought to reflect the actual situation in the region.
Community-based integrated care system and implementation
Based on the above results, further research is needed to reveal how host societies can enrich opportunities for immigrants’ mental health and improve access to social networks for support. There is an international movement toward developing a community-based integrated mental health service, in which mental health professionals and policy makers work together [52-54]. Recent review articles have suggested that an integrated care system for young people was effective for the prevention of mental illness and for early intervention [40]. Some countries have begun to implement school-based programs for supporting the mental health and psychosocial wellbeing of young immigrants [55]. We have undertaken a project named MEICIS (Mental health and Early Intervention in the Community-based Integrated care System), which is funded by the Ministry of Health, Labour, and Welfare of Japan. The present results suggest that an optimal community-based integrated mental health care system that includes early consultation and intervention for foreign residents is necessary. The use of the Consolidated Framework for Implementation Research (CFIR), which has guided and assessed initiatives in community-based healthcare [56-58], seems promising to establish such a system.