The Micronesian islands that form the Republic of Palau, situated about 500 miles east of the Philippines, boast the sun-washed beaches and lush greenery of a tropical paradise. But behind the picture-postcard scenery lurks a disturbing mental-health mystery. For some reason, Palau has one of the highest rates of schizophrenia in the world.
Although researchers routinely assume that this devastating fragmentation of thought and emotion occurs in 1 percent of people everywhere, it afflicts 1.7 percent of the approximately 17,000 Palau residents at some time in their lives. Among Palauan men, schizophrenia’s prevalence soars as high as 2.8 percent. Yet in other parts of Micronesia, the schizophrenia rate dips as low as 0.4 percent.
Such variations, which also crop up elsewhere in the world, illustrate the dangers of assuming that an average prevalence rate of 1 percent applies to any particular location. Differences in schizophrenia’s prevalence from one place to another reflect the influence of environmental and social forces on a disorder often regarded as the product solely of wayward genes and brains, says anthropologist Roger J. Sullivan of California State University in Sacramento.
Although it has been described and pondered by clinicians for the past century, schizophrenia consists of a grab bag of symptoms in search of an explanation. Major elements of the disorder include hallucinations, delusions, apathy, inability to interact with others, blunted or inappropriate emotions, and distorted thinking. Schizophrenia typically emerges in young adults. Doctors 100 years ago described it as a progressive disease of the brain, but many mid-20th-century clinicians attributed schizophrenia to disturbed family relationships. The pendulum then swung back to a biological and genetic emphasis, where it remains.
Research on Palau conducted by Sullivan and his colleagues underscores how environmental and cultural challenges interact with the numerous genes that studies have linked to schizophrenia. The research also suggests that schizophrenia hits people harder in Palau than it does in many other parts of the world. This finding challenges a widespread assumption—based on an ongoing mental-health study launched by the World Health Organization (WHO) in 1967—that family and social life in developing countries provide buffers against psychosis that aren’t available in big cities and developed regions.
“We have to get past the idea that schizophrenia is necessarily milder outside of urban settings and start asking about stressors in any society that influence this condition,” Sullivan says.
Moreover, new Palau findings—published in the April Current Anthropology along with comments from six researchers—contribute to growing evidence that schizophrenia especially targets two groups: men and recent immigrants to various countries.
“Schizophrenia is not the egalitarian disorder that we once thought it was,” remarks psychiatrist John J. McGrath of the University of Queensland in Australia.
Sullivan knows that he’s looking at schizophrenia in a counterintuitive, controversial way. He says that his evidence suggests that traditional, small-scale societies aggravate schizophrenia more than modern, industrialized ones do. In a major city, a person who hears hectoring voices and feels controlled by space aliens can retreat from the stress of social life into anonymity and solitude. But “in a small-scale setting, you can’t choose not to participate in social interactions, even if you have schizophrenia,” Sullivan says.
In 1995 and 1998, he and his coworkers studied a total of 49 men and 21 women receiving outpatient treatment for chronic schizophrenia or for a mix of schizophrenia and depression at Palau’s main hospital. Volunteers averaged 39 years of age and had experienced schizophrenia symptoms for more than a decade. Physicians had prescribed antipsychotic medication to most of them.
Schizophrenia is the same illness in Palau as it is in the United States and other developed countries, the researchers hold. In standard psychiatric interviews, Palauan patients reported much the same array of symptoms as 240 individuals hospitalized for schizophrenia in New York City did around the same time in a separate study.
A common biological marker of schizophrenia also characterizes many of the Palauan patients, according to Sullivan’s team. About 55 percent of the islanders display disturbed eye tracking of objects moving through their visual fields. Several previous studies had found that a comparable proportion of patients with schizophrenia living in developed countries, as well as many of their immediate relatives without the disorder, share this genetically influenced trait.
Some researchers suspect that excessive consumption of alcohol and other drugs among individuals with schizophrenia on Palau exacerbates the condition. Yet, in the new study those who engaged in such behavior actually displayed milder symptoms. Consider betel nut, a stimulant chewed by millions of people from eastern Africa to the Pacific. Among the Palauan patients, the 40 frequent betel nut chewers suffered from milder hallucinations and delusions than did the 30 others who never or rarely chewed the substance. Brain-altering chemicals in betel nuts may quell hallucinations and delusions, the researchers propose in the April American Journal of Psychiatry.
Traditional social practices in Palau ease the experience of schizophrenia for young women and worsen it for young men, the scientists suggest. Signs of schizophrenia first appear as members of both sexes face the stressful task of moving from childhood dependency into adult roles. However, a Palauan woman with the disorder will usually receive support and protection from her family and clan. If necessary, she will continue to live at her family’s house.
In contrast, a mentally ill man on Palau typically receives scant family and clan support. He has few job options and little ability to fulfill customary obligations to repay family members for their prior assistance. As an undesirable marriage partner, he misses out on traditional transfers of family wealth to married men.
In other words, young Palauan men with schizophrenia are cultural outcasts. Their society places unattainable expectations on them and provides constant reminders of their failures. The combination of stress and rejection twists their schizophrenia into a much knottier disorder than it would otherwise become, Sullivan asserts.
He plans to explore this proposal in a 1-year study of symptom progression, social support, and social activities among Palauans with schizophrenia.
Opinions vary widely about the implications of the new schizophrenia evidence from Palau. Perhaps that’s not surprising, given the disorder’s controversial history.
Francis X. Hezel, director of an organization called Micronesian Seminar that conducts research and provides pastoral care in Micronesia, welcomes a focus on the high rate of male schizophrenia in Palau. Sullivan’s report “is a summons to take seriously once again environmental factors that seem to have long been sidelined, if not ignored, in general schizophrenia studies,” Hezel says.
Still, much remains unknown about how culture and biology foster schizophrenia, remarks psychiatrist Robert Barrett of the University of Adelaide in Australia. Researchers need to examine the role of “that universal cultural commodity, stigma,” which may occur with special intensity in small, island populations, Barrett says. The possibility that a distinctive genetic profile contributes to schizophrenia on Palau also deserves scrutiny, he adds.
But psychiatrist Marina Myles-Worsley of the State University of New York Upstate Medical University in Syracuse rejects the new report’s implication that schizophrenia inflicts especially devastating effects on inhabitants of developing nations such as Palau. Sullivan’s team failed to study the many Palauans with schizophrenia who cope without medication or any other formal treatment, Myles-Worsley asserts.
In this close-knit island society, schizophrenia sufferers and their families may tolerate the disorder better and experience less distress than their counterparts in developed countries do, the New York investigator suggests. Palauan women with schizophrenia may often go untreated and uncounted in prevalence studies, she adds, because they don’t engage in drug abuse, criminal acts, or other behaviors that occasion treatment referrals for men.
In a 1999 study, Myles-Worsley and her colleagues identified 160 Palauans with strictly defined schizophrenia. Most either had never been prescribed antipsychotic medication or had taken medication for a few months, giving it up as soon as their symptoms had improved. Of 62 Palauan teenagers with schizophrenia or related disorders described by Myles-Worsley’s group in a 2006 publication, only three males had received treatment with antipsychotic drugs.
The latest data from the international WHO investigation still indicate that people with schizophrenia generally suffer milder symptoms and function better in developing countries than they do in developed nations, says anthropologist Kim Hopper of Columbia University. Those findings appear in a 2007 book edited by Hopper and his colleagues and titled Recovery from Schizophrenia: An International Perspective (Oxford University Press).
However, much of the positive outlook for schizophrenia in the developing world comes from evidence gathered in India, Hopper notes. In that country, families respond to the stigma surrounding mental illness by making extraordinary efforts to support ill individuals and participate in their treatment.
Often forgotten is the fact that, even in Western countries, a majority of people with schizophrenia show remarkable improvement over several decades if provided with social and job programs.
“Specific local characteristics in a community affect the course and outcome of schizophrenia,” Hopper says. “‘Developed’ versus ‘developing’ countries are lousy categories to use in thinking about this issue.”
Migration presents serious challenges to mental health, especially for Africans and other dark-skinned people moving into largely white areas of western Europe, according to psychologist Elizabeth Cantor-Graae of Lund University in Malmö, Sweden, and psychiatrist Jean-Paul Selten of Utrecht University in the Netherlands. Selten says that neither psychiatrists nor politicians nor immigrants themselves want to face the implications of “the silent epidemic of psychotic disorders among immigrants from non-Western countries in western Europe.”
Cantor-Graae and Selten combined and analyzed results from 18 studies, published between 1977 and 2003, of new schizophrenia cases among first- and second-generation immigrants. One investigation took place in Australia; the rest focused on Denmark, the Netherlands, the United Kingdom, and Sweden.
First-generation arrivals to these countries develop schizophrenia at more than twice the rate observed in native-born groups, the researchers reported in 2005. Schizophrenia affects an even greater proportion of second-generation immigrants, Cantor-Graae and Selten say.
Black immigrants from developing countries displayed especially elevated rates of new cases of schizophrenia. Being a dark-skinned immigrant to a primarily white nation is second only to having family members already diagnosed with the disease as a risk factor for schizophrenia, the researchers conclude.
They suggest that the experience of “social defeat” among immigrants promotes severe mental illness. Social defeat arises when an individual is forced into a menial position as an outsider, unable to attain the social rewards of a dominant group. Although scientists have studied this phenomenon in rodents and monkeys, they know little about how it works among people.
Palauan men with schizophrenia who fall short of their culture’s expectations may become mired in social defeat, suggests Hopper.
Intriguingly, half the patients studied by Sullivan’s team lived away from Palau for some period of time as young adults and then returned. Their initial episodes of schizophrenia frequently occurred abroad, raising the possibility that immigration experiences contributed to the disease.
Despite such clues, researchers have yet to identify any environmental measure that can claim major responsibility for fluctuations in schizophrenia rates, cautions psychiatrist Assen Jablensky of the University of Western Australia in Crawley, who headed the WHO international schizophrenia study.
Schizophrenia may well encompass many diseases, each with its own mix of causes, he notes. If so, efforts to pin down the ailment’s population rates must await discovery of gene variations that prompt its different forms, Jablensky says.
Until then, high schizophrenia rates in Palau will remain a troubling enigma in paradise.