Amish Study Explores Roots Of Bipolar Disorder

Symptoms of bipolar illness were found to occur more often among Amish youth who had at least one parent with bipolar illness, according to researchers who following the youngsters for 10 years. None of the children, however, was diagnosed before puberty.

“As our population of high-risk Amish youths aged, there was a shift from the more internalizing symptoms to those that are more often thought of as manic-like behaviors: high energy, decreased sleep, excessive and loud talking, and problems in concentration,” wrote Jon Shaw, M.D., a professor of psychiatry and behavioral science and project psychiatrist in the Affective Disorders Project at the University of Miami, and four colleagues. Their study appeared in the November Journal of the American Academy of Child and Adolescent Psychiatry.

The Old Order Amish community has drawn the interest of researchers in several fields because it is a largely endogamous group that has separated itself culturally and genetically from the general population. Members may leave the community from time to time, but they don't allow conversion, said Shaw. “There's been no new DNA since they came to America.”

The sample contrasted 14 families, including 110 children, in which at least one parent had been diagnosed with bipolar I disorder with 13 matched control families with 112 children. At the study's 10-year mark, 41 percent of the children with a bipolar parent exhibited some risk for bipolar disorder, compared with 16 percent of those without a bipolar parent. Some of the 55 clinical features the researchers recorded were also reported by the control families, suggesting a lack of reporting bias on the part of parents.

Children of bipolar I parents had significantly more frequent reports of anxiety, poor attention, excitability, hyperalertness, labile moods, somatic complaints, stub-bornness, and role impairments in school—all of which were noted in the study's previous seven-year report. Five additional items reached significance by the 10th year of the study: high energy, decreased sleep problems, excessive talking, loud talking, and problems with thinking or concentration. Symptoms less common at 10 years than at seven were low energy, anger dyscontrol, fearfulness, and sensitivity.

No children below the age of 12 and only two postpubertal youngsters met DSM-IV criteria for bipolar I disorder.

“We don't see the subtype of pediatric mania we see in other populations,” said Shaw in an interview. Nor was there early onset of aggression, rage reactions, sexual promiscuity, classical attention-deficity/hyperactivity disorder, or mood or emotional dysregulation, he said.

Prodromal Status Not Certain

This shift in symptom frequency is one of the study's interesting findings, said psychologist Aude Henin, Ph.D., an instructor in psychiatry at Harvard Medical School and scientific coordinator of training and quality assurance at Massachusetts General Hospital. Henin has studied the risk of psychiatric illness among children of parents with bipolar disorder. Symptoms have been studied cross-sectionally, so showing their course prospectively was useful, she said in an interview.

“It's too soon to say if these are prodromes of bipolar I,” said Henin. “Are these early anxiety, mood, and behavioral symptoms actually signs of something to come? Since bipolar is typically one of the later disorders to onset, the goal is to identify its early harbingers. What's not clear is whether this is bipolar disorder or something else.”

The Amish typically have large families; those in the study averaged eight children. For cultural reasons, the researchers interviewed only parents, not the children or their teachers. The researchers devised a series of questions called the Child and Adolescent Research and Evaluation interview (CARE) to look for early signs and symptoms of bipolar risk.

“Existing standardized interview guides for children were culturally inappropriate for the Amish, having been designed for diagnosis and not fully applicable to well youngsters,” wrote Shaw. The CARE questions were thus designed especially for interviewing the Amish. It has not been tested on other populations.

“The format was [intended] to go beyond `paper and pencil' instrumentation and assess by a semistructured interview format both formal and informal information regarding the child's patterns of behaviors over time,” said Shaw. “The nature of the Amish community, with its own culture, is such that we could not use the standardized instruments used in other studies.”

Methodology Has Limits

Interviewing the child remains the primary diagnostic tool, despite imaging or other tests. While perhaps necessary, the researchers' use of a nonstandard interview scheme may make it harder for other scientists to interpret the Amish study and or to compare it with other research, said Henin. “There may be more subtle symptoms or mood states that the parents can't appreciate,” she said.

Filtering behavior through the views of this set of parents may also require some perspective. To an Amish mother or father, “disruptive behavior” may mean a child taking off her galoshes on a rainy day or a teenager going to the store for a six-pack of soda.

As another example of cultural influences on their research, Shaw and his team noted that their previous reports of disruptive behavior in five teenaged boys above the age of 16 should not be interpreted as prodromal symptoms of bipolar disorder. Formal education among the Amish stops at eighth grade, and young men are tacitly granted leeway to move outside traditional social boundaries until they settle down and marry in their late teens or early 20s.

More critically, the boundaries between prodrome and illness are not clear from the report, added Gabrielle Carlson, M.D., a professor of psychiatry and behavioral science at Stony Brook University School of Medicine, Stony Brook, N.Y., in a commentary published with the study.

“In a prodromal study of bipolar disorder in high-risk offspring, why are there no reports of people who have developed the condition? The point of high-risk studies is to establish who develops the disorder; otherwise, prodromal is a meaningless term. The fact that the authors continue to report people at risk of a disorder rather than reporting on rates of the disorder itself is not helpful.”

“Dr. Carlson has raised some interesting questions, but this is a clinical study with all its strengths and weaknesses,” said Shaw in an interview. Two adolescents in the program, both with a bipolar I parent, did eventually manifest the onset of disorder according to DSM-IV standards. However, there were no prepubertal examples of children with the disorder, he said.

While acknowledging the limitations of the study, Henin said that it deserves attention because of its long-term, prospective approach and its close attention to the interaction between the sociocultural environment and the individual's genetic heritage.

An abstract of “A 10-year Prospective Study of Prodromal Patterns for Bipolar Disorder Among Amish Youth” is posted at<www.jaacap.com by searching under the November issue. ▪