Children With Bipolar Parents at Increased Risk for the Disorder CME

News Author: Pauline AndersonCME Author: Laurie Barclay,

March 11, 2009 — New research shows that children of a parent with bipolar disorder face a 14-fold increased risk of developing this illness. These children appear to be especially prone to early-onset bipolar disorder, and if they have 2 parents with the disease, their risk of developing bipolar disorder is even greater.
The research also found that offspring of a parent with bipolar disorder are at least twice as likely to develop a mood or anxiety disorder compared with youngsters whose parents do not have bipolar disorder.
These results suggest clinicians should probe more deeply into the mental health of children of patients with bipolar disorder and provide early intervention when necessary.
"If a child has problems and the problems are affecting his functioning, that child should be assessed," the study's lead author, Boris Birmaher, MD, from the University of Pittsburgh Medical Center/Western Psychiatric Institute and Clinic, in Pennsylvania, told Medscape Psychiatry.
The study, part of the Pittsburgh Bipolar Offspring Study, looked at parents with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, diagnosis of bipolar disorder and a random sample of community controls without bipolar disorder, matched for age, sex, and neighborhood of residence, who had no first-degree relatives with bipolar disorder. Also included in the study were the parents' offspring aged 6 to 18 years.
Among the final sample of 233 parents with bipolar disorder were 10 families that had 2 parents with this disorder. A final control sample of 143 parents included 79 with non–bipolar-disorder psychiatric disorders and 64 without any psychopathology. In addition, 388 offspring of parents with bipolar disorder and 251 children of control parents were assessed in the study.
Parents were interviewed to determine psychiatric disorders, family psychiatric history, and other variables such as family environment and exposure to negative life events. They were also asked about their children, and the children were interviewed separately for the presence of psychiatric disorders. All but the statisticians were blinded to the parental diagnoses.

Early-Onset Problem
The analysis showed that the children of a mother or father with bipolar disorder had significantly more bipolar-disorder–spectrum disorders (41 [10.6%] of 388 children) than offspring of control parents (2 [0.8%] of 251 children). Children with 2 parents with bipolar disorder had an even higher risk and were 3.6 times more likely to have bipolar disorder than those from families with only 1 parent with bipolar disorder.
However, because there were only a handful of such families in the study, "I would be careful" about drawing conclusions, said Dr. Birmaher in an interview. "The sample is so small that we didn't want to make too much noise about this."
Most of the bipolar disorder uncovered among children in the study had not yet become full-blown, said Dr. Birmaher. "By our definition, the type of bipolar disorder that most of these kids have is subclinical; they have depressions and they have anxiety disorders. Maybe this is the beginning of the illness."
The authors stressed that because children in the study have not reached the age where the risk for bipolar disorder is at its peak, their risk for bipolar disorder will likely continue to increase.
The study confirmed that bipolar disorder "is an early-onset problem," said Dr. Birmaher. Of those 41 children with bipolar disorder whose parent also had bipolar disorder, 31 (75.6%) had onset before age 12 years.
Although the study set age 4 years as the minimum age for onset of bipolar disorder, some parents reported their child's bipolar-disorder–like symptoms began even before that age. "The younger the kid, the more difficult it is to diagnose," said Dr. Birmaher. "We unfortunately don't have a blood test or an x-ray to confirm it."
The parents themselves developed bipolar disorder at an early age. Approximately 64.0% of those with bipolar disorder reported that their mood disorder started when they were younger than 20 years, 48.0% when they were younger than 17 years, and 18.0% when they were younger than 13 years.
These study results might spur a more rapid diagnosis of children who show these early symptoms — an important step, because early treatment is associated with better outcomes. In the past, it took approximately 10 years from the onset of the bipolar illness to get proper diagnosis and treatment, said Dr. Birmaher. "We don't want that to happen now; we want people to be more aware."
Some people — including some professionals in the field — still are not convinced that children can develop bipolar disorder, he said.

Do Not Panic
But Dr. Birmaher does not want his study to create panic. Just because a parent has bipolar disorder does not necessarily mean his or her child will develop it. "It's just like other illnesses. For example, you can have a parent with diabetes and you yourself never develop diabetes," he said. And as with other disorders, he said, "bipolar disorder is not 100% genetic; there's a role for the environment, and such things as stress and the use of drugs can trigger the disorder."
Gabrielle A. Carlson, MD, from Stony Brook University School of Medicine, in Stony Brook, New York, agreed that the genetic story behind bipolar disorder is complex. She noted that offspring of parents with bipolar disorder are still at much higher risk of developing psychiatric illnesses other than bipolar disorder (25.8% of the bipolar-disorder offspring sample met criteria for anxiety disorder, 19.1% for disruptive-behavior disorder, and 24.5% for attention-deficit/hyperactivity disorder).
Asked to comment on the implications of the study, Dr. Carlson said the issue of early intervention in youngsters with bipolar disorder is "dicey." "From a clinician standpoint, the need to respond therapeutically to symptomatic children who are at risk is clear, but the question of how to respond is less clear," she told Medscape Psychiatry.
"Most symptomatic children are not likely to develop clear-cut bipolar disorder; some disorders like anxiety disorders require treatments that are contraindicated in bipolar disorder; and so far, there are no data that suggest that every psychiatric disorder that emerges in high-risk offspring is responsive to treatment for bipolar disorder," she said.
Whereas previous studies have looked at the rate of bipolar disorder among children of patients with bipolar disorder, most of that research was undertaken when the children had reached adulthood. This current study is among the first to look at offspring when they are still young, said Dr. Birmaher, adding that the study sample size is large and adjusted for demographic data and other confounding factors.
The National Institute of Mental Health supported this study. Dr. Birmaher has participated in forums sponsored by some pharmaceutical companies (Solvay, Abcomm, and Jazz Pharmaceuticals). Coauthor David Kupfer, MD, also from the University of Pittsburgh Medical Center, has served on the advisory boards of Pfizer, Eli Lilly, Forest Pharmaceuticals, F. Hoffman-LaRoche, and Solvay/Wyeth Pharmaceuticals and has been a consultant to Servier Amérique.
Arch Gen Psychiatry. 2009;66:287-296.
Pearls for Practice
Offspring of parents with bipolar disorder are at high risk for psychiatric disorders and, specifically, for early-onset bipolar disorder spectrum disorders. These findings further support the familiality and validity of bipolar disorder in youth and highlight the need for early identification and treatment.
Compared with offspring of control parents with high socioeconomic status, offspring of parents with bipolar disorder with high socioeconomic status showed more disruptive behavior disorders and any Axis I disorders. The risk of having offspring with bipolar disorder was greater in families in which both parents had bipolar disorder vs families with only 1 parent having the illness.