Migrants at elevated risk for psychotic disorders, but not for non-psychotic bipolar disorder – new PsyLife paper

by Ashild Kummen

Image result for migrationMigration can be a difficult process, involving a multitude of stressors. This may make some migrants more vulnerable to mental health problems, and previous research have found migrants to be at an elevated risk for psychotic disorders, especially with visible minorities, such as people from black Caribbean and African backgrounds in the UK . In regard to bipolar disorders, however, the research is more mixed, and enquiries have rarely distinguished between bipolar disorders with and without psychotic symptoms.

A new paper from our Ph.D. student Jennifer Dykxhoorn, published today in Psychological Medicine, sheds light on whether the increased risk of psychotic disorders extends to bipolar disorder with and without psychosis. In her paper, Jen hypothesised that migrants were at elevated risk for schizophrenia and affective psychoses (such as bipolar disorder with psychotic features), but not for bipolar disorders without psychotic symptoms. Longitudinal data from almost 1.8 million Swedish residents born between 1982-1996 were collected, with differences by migrant status, age-at-migration and region of origin investigated. Consistent with previous findings , we predicted that migration during early childhood would increase the risk of being diagnosed with a psychotic disorder.

Findings

Compared with the Swedish-born population, migrants and their children were at elevated risk for all psychotic disorders. This included schizophrenia and schizoaffective disorder, where migrants and their children were, on average, twice as likely to be diagnosed. First-generation migrants were also at double the risk for other types of non-affective psychoses. Rates of bipolar disorder with psychosis were also elevated in migrants and their children by 42% and 22%, respectively, compared to the Swedish-born population. In stark contrast,  migrants were up to 40% less likely to be diagnosed with non-psychotic bipolar disorders than the Swedish-born population. For second-generation migrants, risk of non-psychotic bipolar disorder was similar to Swedish-born rates.

While we predicted that migrating during early childhood would elevate risk of psychotic disorders, our findings did not support this. Instead, there was a pattern of increased risk at all ages of immigration to Sweden for psychotic disorders.. By contrast, all ages at immigration were associated with lower risk for bipolar disorder, except for those who migrated during infancy, where incidence rates were closer to the Swedish-born population.

In accordance with previous research by the PsyLife team , African migrants were at highest risk for all psychotic outcomes, including being five times more likely to be diagnosed with schizophrenia. In total, migrants from all origins (except other Nordic origin) were at elevated risk for all psychotic disorders, compared to the Swedish-born population.

Possible explanations

Migrants are exposed to several difficulties relating to the process of migrating and the minority status. Jen’s paper found that the incidence rates for psychotic disorder and bipolar disorders (without psychotic symptoms) is largely different, with higher risk for psychotic disorders and lower risk for bipolar disorders compared to the Swedish-born population. This could suggest that the stressors of migrating and post-migration life have a specific effect on developing psychotic disorders. This is consistent with some research on the neurodevelopmental origins of psychotic and non-psychotic bipolar disorders, conveying these origins are distinct. For example, patients with schizophrenia and bipolar disorders with psychotic features are observed to have premorbid cognitive deficits, which have not been consistently found in non-psychotic affective disorders (Reichenberg et al., 2002; Trotta et al., 2014). Our research suggests further work is now required to test whether certain environmental factors impact on specific neurobiological pathways to influence the occurrence of certain types of mental health problem.

 

PsyLife references

Other references

  • Reichenberg, A., Weiser, M., Rabinowitz, J., Caspi, A., Schmeidler, J., Mark, M., Kaplan, Z, & Davidson, M. (2002). A population-based cohort study of premorbid intellectual, language and behavioural functioning in patients with schizophrenia, schizoaffective disorder, and nonpsychotic bipolar disorder. Psychiatry: Interpersonal and Biological Processes, 159, 2027-2035.
  • Trotta, A., Murray, R. M & MacCabe, J. H. (2014). Do premorbid and post-onset cognitive functioning differ between schizophrenia and bipolar disorder? A systematic review and meta-analysis. Psychological Medicine, 45, 381-394.

Incidence and risk factors of psychotic disorders in older people

Whilst it is known that the first episode of a psychotic disorder usually occurs during adolescence or early adulthood (Kessler et al., 2007), there is a considerable amount of people also experiencing the onset in old age, termed very late-onset of schizophrenic-like psychosis (VLOSLP).Over a year, between 0.1- 0.5% of the population past 65 years old are diagnosed with or have an existing diagnosis of schizophrenia (Howard, Rabins, Seeman & Jeste, 2000).

Robust research in regard to the variance in incidences of VLOSLP and its associated risk factors is important to inform public mental health in hopes of improving interventions for affected individuals. Yet, there is a limited amount of epidemiological research on VLOSLP. The studies that do investigate an onset of a psychotic disorder past 60 or 65 years old, are mostly cross-sectional studies of small samples with limited generalisability. Furthermore, their findings lack in replication. In tackling these limitations, Jean Stafford, one of our PhD students in the PsyLife team has conducted a systematic review on the research there is on incidence rates and different risk factors for VLOSLP. She also conducted a longitudinal cohort study looking into risk factors identified in previous research, including gender, age and sensory impairment as well as unexplored areas such as social economic status, migrant status, social isolation and trauma.

The systematic review and meta-analysis found 41 papers (dated between 1960 and March 2016) that looked at incidence cases of patients diagnosed with a psychotic disorder past 65 years old, not including cases related to dementia, organic and drug-induced psychoses. The majority of these papers were rated of high and average quality, and 25 were included for quantitative analysis. The pooled incidence rate showed that, every year, 7.5 out of 100 000 people over 65 years old were diagnosed with schizophrenia. Moreover, psychoses related to an affective disorder had a yearly rate of 30.9 new cases per 100 000 people. Incidence rates for non-affective psychoses differed largely between studies, and a pooled estimate was not possible. However, the cohort study offers some clarification as it investigated only non-affective psychotic disorders.

The cohort study consisted of over 3 million participants past age 60, all Swedish residents born between 1920 and 1949. Large-scale data collection was possible as every resident in Sweden is given a national identification number that is recorded within a range of health and administrative services. This revealed an incidence rate for non-affective psychotic disorders of 37.66 per 100 000 people every year.

Stafford also investigated the influence of gender and age. The systematic review found reports that women were more likely to be diagnosed than men past age 65 within all branches of psychotic disorders analysed (non-affective, affective psychoses and schizophrenia). The cohort study supported this, with participants diagnosed with a non-affective psychotic disorder past 60 years old being 60% female. In regard to age, the systematic review revealed previous research has been mixed. However, the cohort study revealed a significant increase with age, with differing patterns between men and women. Past 80 years old, women were at risk for VLOSLP at an accelerated rate.

The cohort study also collected data on other possible risk factors, such as migrant status, income, family and sensory impairments. Migrants from Africa, North America and Europe were at elevated risk compared to the rest of the population. This is an association also found in younger populations , possibly explained by the stressors encompassed in migration. Furthermore, low income at age 60 significantly predicted a higher future risk of VLOSLP. In an investigation of family history, it was found that participants with children diagnosed with a psychotic disorder were twice as likely to have VLOSLP. Looking at social isolation; participants with no children and/or no partner 2 years before exiting the study were at elevated risk. Experiencing the death of a partner 2 years before also led to increased risk, whilst the death of a child before age 18 had no association and the death of a child at infancy had weak evidence for elevated risk. These could be indicators of the influence of trauma. Contradictory to previous research (Cooper & Porter, 1976; Cooper et al. 1974), participants with sensory impairments were less likely have VLOSLP compared to the general Swedish population. However, this result could reflect an under-detection of psychiatric disorders in people with physical health issues (Roberts, Roalfe, Wilson & Lester, 2007)

In conclusion, these results indicate that people with VLOSLP were more likely to have social disadvantages, such as lower income and social isolation. This could be interpreted two ways; either there is causal link where the stressors of inequalities lead to increased risk of a psychotic disorder, or that those with premorbid symptoms of a psychotic disorder will subsequently suffer disadvantages due to lower functioning, although VLOSLP patients have been shown to have higher premorbid functioning (Castle et al., 1997). Older women are at particularly prominent risk, indicating this is a group deserving of more clinical recognition.

Full version of the systematic review can be found here, and the cohort study here.

 

PsyLife References:

 

Other references:

  • Castle, D.J., Wessely, S., Howard, R., et al. (1997). Schizophrenia with onset at the extremes of adult life. Int J Geriatr Psychiatry, 12, 712–717.
  • Cooper, A. F., Curry, A. R., Kay, D. W., Garside, R. F. & Roth, M. (1974). Hearing loss in paranoid and affective psychoses of the elderly. Lancet 2, 7885, 851–54.
  • Cooper, A. F. & Porter, R. (1976). Visual acuity and ocular pathology in the paranoid and affective psychoses of later life. Journal of Psychosomatic Research 20, 107–114.
  • Howard, R., Rabins, P. V., Seeman, M. V., & Jeste, D. V. (2000). Late-onset schizophrenia and very-late onset schizophrenia-like psychosis: An international consensus. American Journal of Psychiatry, 157, 172–178.
  • Kessler, R. C., Amminger, G. P., Aguilar-Gaxiola, S., Alonso, J., Lee S., & Utsun, T. B. (2007). A controlled family study of late-onset non-affective psychosis (late paraphrenia). The British Journal of psychiatry, 170, 511-514.
  • Roberts, L., Roalfe, A., Wilson, S., & Lester, H. (2007). Physical health care of patients with schizophrenia in primary care: a comparative study. Fam Pract, 24, 34–40.

 

 

PsyLife research in Europe’s cultural capitals

It’s an exciting week for the PsyLife group. We’re presenting no fewer than 6 research papers in two of Europe’s most historic cultural capitals – Vienna and Florence.

Recent PsyLife Phd graduate, Dr Hannah Jongsma, and current PhD student Jean Stafford will both be in Florence for the 6th Biennial conference of the Schizophrenia International Research Society  Hannah will be speaking as part of a symposium (Sala Verde, Sat 7 April, 10-12pm) on the prevention of psychosis, talking about her recent findings from the EU-GEI study . Congratulations to Jean, who won a Young Research travel award to attend the conference, and will be giving a poster presentation on variation in the incidence of very-late onset psychotic disorders using nationwide longitudinal cohort data. Her poster is S134 and she will be presenting in Poster Session III on Saturday 7th April, 12-2pm.

Meanwhile, over in Vienna, we have a PsyLife symposium at the 18th 19th(!) Section meeting of European Psychiatric Association’s Epidemiology and Social Psychiatry section. Our symposium, entitled Environments and psychosis: examining the causal evidence will feature our latest findings from the ALSPAC birth cohort and the SEPEA study on how neighbourhood environments are related to psychotic outcomes and comorbid personality disorders. We have talks from Dr James Kirkbride, Dr Francesca Solmi, Ka-Young Ban (PhD student) and Tayla McCloud (rortation PhD student). Do come along and find out more: Kursraum 22, Friday 6th April, 2-3.30pm.

Finally, we wanted to say a massive thank you and congratulations to Francesca, who will be leaving the PsyLife group to begin her own Sir Henry Wellcome Fellowship on the epidemiology of eating disorders. Francesca has published several key papers with the group in her three years here , with several more still to come. We are sure you will go on to great successes, and thank you for being such an inspiring, helpful and knowledgeable member of the group!

References

Congratulations Dr Hannah Jongsma!

Image result for hannah jongsmaThe PsyLife group are thrilled that group PhD student Hannah Jongsma passed her viva at the University of Cambridge last week, with a recommendation that she be awarded a PhD following (just two) minor corrections to her thesis. In her thesis, entitled The role of the social environment in explaining variance in incidence of psychosis and higher rates of disorder in minorities,  Dr Jongsma explored variation in the incidence and risk of psychotic disorders using epidemiological data from the EU-GEI study. In particular she was interested in understanding variation in incidence by place, and last month published the first output from her thesis in JAMA Psychiatry, in a paper exploring reasons for 10-fold variation in rates of psychotic disorder across 17 centres in the EU-GEI study . She was also interested in understanding variation by ethnicity and migrant status, exploring the roles that psychosocial disadvantage and social distance played on these factors. 

We would like to congratulate Dr Jonsgma on her success, and wish her the best of luck in her future career. Dr Jonsgma will continue as a postdoctoral research associate in the Department of Psychiatry at the University of Cambridge, and we look forward to seeing more outputs published from her PhD over the next year or so. 

Well done!

Reference

Are cats bad for your mental health? Probably, not.

Over the past few years, a number of scientific studies and media outlets have reported that Toxoplasma Gondii (T. Gondii) infection could increase a person’s risk of experiencing adverse mental health outcomes – including schizophrenia, suicide, and intermittent rage disorder.

Since domestic cats are the primary hosts of T. Gondii (i.e., they provide an environment within which this parasite can reproduce) some people have speculated that cat ownership may put people at increased risk of mental illness, by exposing them to T. Gondii infection. While a handful of small studies have found evidence to support a link between cat ownership and psychosis, most of these investigations had serious methodological limitations (e.g.: relying on recall of past cat ownership, small sample sizes, missing data, lack of control for other explanations), which may have biased their findings.

To tackle these limitations, we used data from a large, longitudinal sample of approximately 5,000 children, a sub-group of 14,000 children born in the former region of Avon, (UK) between 1991 and 1992. Unlike previous studies, we were able to follow people over time, from birth to late adolescence, and address a number of the limitations of previous studies, including controlling for alternative explanations (including socioeconomic status, ethnicity, other pet ownership and over-crowding) and taking into account missing data. We studied whether mothers who owned a cat: 1) while pregnant; 2) when the child was 4 years old; and 3) 10 years old, were more likely to have children who reported psychotic symptoms (e.g.: experiences of visual or auditory hallucinations, and of paranoia) in early (age 13) and late adolescence (age 18).

We found that children who were born and raised in households that included cats at any time period were not at a higher risk of having psychotic symptoms when they were 13 or 18 years old. This finding in a large, representative sample was robust against issues of missing data and alternative explanations. Although most people who experience psychotic symptoms in adolescence will not develop schizophrenia later in life, they can indicate an increased risk for such disorders.

It is important to remember that there is evidence linking T. Gondii exposure in pregnancy to risk of miscarriage and stillbirth or health complications in offspring. We therefore recommend that pregnant women should continue to avoid handling soiled cat litter and other sources of T. Gondii infection (such as raw or undercooked meats or unwashed fruit and vegetables). That said, data from our study suggests that cat ownership during pregnancy or in early childhood does not pose a direct risk for later offspring psychotic symptoms.

Psychosis in the field

Click to visit the study webpage (external)New research led by Dr James Kirkbride from the PsyLife group, Division of Psychiatry, UCL, has shown how psychosis risk varies in more rural populations than previously studied in England. The findings, published last week in the American Journal of Psychiatry, reveal that rural regions see a significant rate of new cases of psychotic disorder in their populations. This is important because service planners need to ensure all people developing a first episode of psychosis can get quick, timely access to specialist mental health services such as Early Intervention teams.

The study was conducted in the East of England, in three counties – Cambridgeshire, Norfolk and Suffolk – and tried to identify all young people (aged between 16 and 35 years old) presenting to mental health services for the first time due to psychosis over a 3.5-year period. During this time, the study identified over 680 people who met diagnostic criteria for first episode psychosis living in this region, corresponding to an incidence rate of 34 new cases per 100,000 people per year.

The study also revealed that the risk of developing psychosis varied by important characteristics of both individuals and their environments. For example, although the study was conducted in a more rural setting than many previous epidemiological studies of this type , the authors found that the rate of disorder still varied according to how densely populated and deprived the environment was. Rates of psychotic disorder were relatively stable in most parts of the region, but rose in the most deprived and most densely populated regions. While this data is in keeping with earlier research , the study extends previous knowledge by suggesting that there may be a threshold effect in operation; below a certain level of population density or deprivation, there is no increase in risk, but once a certain level is reached, risk begins to shift. This research has not previously been possible in studies which have tended to be conducted in more urban environments.

The study also found variation by individual level factors. As previously established, men were almost twice as likely to experience a first episode of psychosis than women, particularly in their late teens and early twenties when risk is highest for both sexes. There was some evidence that rates were also raised in black and minority ethnic groups, but another paper from the same study will address this issue in more detail, and is currently under review.

You can read the full version of these findings here, or read about further overage of the findings from Psychiatric News and Medscape.

Reference

A Big Week for PsyLife

336437537It’s been quite a week for the PsyLife lab. First off, we’re delighted to say that one of our PhD students – Jen Dykxhoorn – successfully passed her PhD upgrade at UCL. While we weren’t surprised by this, it reflects a huge amount of work Jen has put in to her PhD on migration and psychosis in the first year. She’s currently writing up some results from her first study on this topic, which we’ll be submitting soon for publication. Jen has developed a great program of research as part of her PhD over the next 3 years, which we’re very excited about. Congrats Jen! Jen’s research is funded by Mental Health Research UK, with subsidiary funding from the Royal Society and Wellcome Trust.

 

We’re also delighted to announce that another PhD student – Jean Stafford – has joined the group to do a mixed epidemiological and psychological PhD on old age psychosis. She’ll be co-supervised by Dr James Kirkbride and Prof Rob Howard in the Division of Psychiatry. Jean spent 3-months with us last year as part of her MRC-sponsored first year PhD rotation scheme. Welcome along Jean!

 

We also welcome Dr Daria Monteforte from the University of Verona who joins us for a 6-month research visit. Daria is a psychiatrist specialising in psychosis. She’ll be gaining research experience during her visit with us. You can read more about what Daria’s up to here.

 

The PsyLife group would also like to pass on its congratulations to the MSc students who did student projects with us in 2015-16. All the projects we supervised addressed interesting epidemiological and mental health service issues with respect to psychosis, and we were impressed by the overall quality. Hopefully several of these will be submitted for peer-reviewed publication in the coming months. Dawid Gondek begins a PhD in longitudinal epidemiology of healthy ageing at the Institute of Education with Professor George Ploubidis, while Lucy Richardson has joined the REACH study with Professor Craig Morgan at the IoPPN as a Research Assistant. Mohammedi Abdolali continues his clinical work as a psychiatrist, armed with new insights from his MSc experiences. Finally, well done to Tom Steare, who continues his studies in mental health.

 

On a final note, a major publication from the PsyLife group has been published this week in the American Journal of Psychiatry. The paper investigates the epidemiology of first episode psychotic disorders, as seen through Early Intervention in Psychosis services in a rural population in England. Until now, very little epidemiological research has been conducted in EIP settings or in rural populations, and this study is an attempt to fill this gap. The paper has also been covered by Psychiatric News.

More Student Success in the PsyLife Lab

Bio picHere in the PsyLife lab we busy working away on lots of exciting hypotheses regarding how the social environment is linked to a greater risk of experiencing psychosis at a later time point.

Now, one of our first-year PhD students, Jen Dykxhoorn has achieved further recognition for her PhD which will focus on the role of social factors underlying the raised rates of psychotic disorders amongst migrants and their descendants. Jen has been awarded a prestigious UCL Overseas Research Scholarship in support of her PhD.

We’re delighted Jen’s research potential has been recognised at this early stage in her career, and we are excited about the progression she will make in her studies over the next three years. Jen’s PhD research is also supported by the Mental Health Research UK (MHRUK)’s John Grace QC Scholarship. Once again, congratulations to Jen, and stay tuned here for exciting findings from her and the rest of the group.

SIRS Travel Award for PsyLife PhD student!

SIRS meetingThis weekend will see the start of the eagerly awaited 5th Biennial Schizophrenia International Research Society (SIRS) conference, taking place in Florence, Italy. The conference will bring together international researchers from all areas of schizophrenia research to discuss the latest findings from the field. It promises to be an excellent meeting, and two members of the PsyLife group, Dr James Kirkrbide and PhD student Hannah Jongsma, will be presenting some of their findings.

We’re delighted to announce that Hannah has won a prestigious SIRS Young Investigator Travel Award to attend the conference. Congratulations! Hannah is in the second year of her PhD on the role of social and environmental risk factors in schizophrenia and other psychoses. To receive this international award is a major achievement and highlights Hannah’s dedication and growing expertise in the field. Hannah will be presenting her findings on cross-national variation in the incidence of psychotic disorders using data from the EU-GEI study. If you are at the conference, her talk will be on Tuesday 5th April, from 3.15pm, in the session on “Epidemiology: roles for environmental risk factors”. James will be presenting his work on age-at-migration in the same session. Do join us if you can.

See you in Florence!

Ciao!

 

Full list of PsyLife presentations at SIRS 2016

  • Hannah Jongsma: Incidence of psychotic disorders in England, France, Italy, the Netherlands, Spain and Brazil: Data from the EU-GEI study, Tues 5th April, 4.30pm-4.45pm: Symposium: Epidemiology: roles for environmental risk factors
  • James Kirkbride: Age-at-migration and risk of first episode psychosis in England: epidemiological evidence from the SEPEA study, Tues 5th April, 3.45-4pm, Symposium: Epidemiology: roles for environmental risk factors
  • James Kirkbride: (Poster S157): The Epidemiology of first episode psychosis in early intervention  in Psychosis services: findings from the SEPEA study, Poster session 1, Sunday 3rd April, 11am – 1pm.

 

Psychosis incidence in refugees to Sweden – cohort study of 1.3 million people

Working with colleagues at the Karolinska Institute we’ve shown that the risk of schizophrenia and other psychotic disorders is raised in refugees to Sweden by up to 3 times that of the Swedish-born population. This risk, was on average, 66% higher than the risk in other (non-refugee) migrants from the same regions of origin. These findings suggest that the additional psychosocial adversities faced by refugee groups may be important in the aetiology of psychosis. You can see a video abstract highlighting the work here, or read the full article published in the BMJ. This work was jointly conducted by our group at UCL and the Department of Public Health Sciences at the Karolinska Institute.