Not all children with bipolar disorder may be getting properly identified because they fall just short of meeting diagnostic criteria for the disorder--criteria that is based on adult experiences--finds a study that examines the characteristics of children and adolescents who have symptoms of mania. The findings, from the first study of its kind to delineate the types of symptoms seen in children with bipolar spectrum disorders, were published today by researchers from the University of Pittsburgh School of Medicine in the Archives of General Psychiatry.
The researchers found that a significant number of children who presented with symptoms of bipolar disorder were just below the threshold of meeting the two primary classifications of bipolar disorder, mostly due to the fact that their manic episodes did not last long enough. However, these youth with "subthreshold" mania were similar in most ways to children and adolescents who met the full diagnostic criteria for bipolar disorder.
"Some children with bipolar disorder have distinct episodes of manic symptoms that last for many days or weeks at a time, just like it classically presents in adults with bipolar disorder. However, we do not know very much about children who have very clear periods of manic symptoms that do not last for several days. The results from this study suggest that some of these kids likely have bipolar disorder," said David Axelson, M.D., assistant professor of psychiatry, University of Pittsburgh School of Medicine and lead author of the study. "We need more research to figure out which kids go on to become bipolar adults, so it is too early to say that every child with brief periods of manic symptoms is bipolar. However, it is reasonable for clinicians to consider the possibility of bipolar disorder in youth who present with mania that does not reach the duration criteria for adult bipolar disorder."
The study assessed the symptoms of 438 children and adolescents between the ages of 7 and 17 years who were diagnosed with bipolar spectrum disorders; participants were enrolled at three centers: Brown University, University of California at Los Angeles and the University of Pittsburgh.
Bipolar disorder, commonly called manic-depressive illness, is characterized by swings between depression and mania and periods with mixed symptoms. As defined in adults by the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV), bipolar disorder consists of two primary subtypes. Bipolar I (BP-I) is characterized by episodes of full-blown mania with or without major depression; Bipolar II (BP-II) involves episodes of less severe mania, called hypomania, and major depression. Significant manic symptoms that do meet the criteria for BP-I or BP-II is often called Bipolar Disorder Not Otherwise Specified (BP-NOS), which also is listed in the DSM-IV but does not have well-defined criteria. BP-NOS was defined for the purposes of this study as having a hypomanic episode without a history of major depressive episodes, having periods of mania that met the DSM-IV duration criteria for a manic episode but fell just short of the symptom criteria, or periods of mania that met the symptom criteria but were of short duration.
Participants and their caregivers were interviewed to assess symptoms, family history and socio-economic status using a host of well-accepted clinical evaluation tools. Data were evaluated to determine differences among the subtypes of bipolar disorder in intensity of symptoms, functional impairment, comorbid diagnoses, family history and manic symptoms.
A diagnosis of BP-I was most common among participants, with 255 (58.2 percent) having symptoms that qualified. A substantial number, 153 (34.9 percent) had a diagnosis of BP-NOS, and a small number, 30 (6.8 percent) had a diagnosis of BP-II.
There were many similarities between BP-NOS and BP-I, including age of onset, duration of illness, rates of comorbid diagnoses, rates of prior major depressive episodes, family history and types of manic symptoms. However, those with BP-I, on average, displayed one more manic symptom than those with BP-NOS and had more intense symptoms and more severe functional impairment. The BP-I subjects also had higher rates of psychosis and psychiatric hospitalization and were more likely to attempt suicide.
The researchers found that most participants with BP-NOS met the symptom criteria for BP-I or BP-II during the time they had experienced their most severe episode, but had not been diagnosed as having either classification because their manic symptoms did not last long enough. As such, the researchers say the duration criteria for BP-I and --II as defined for adults in the DSM-IV may not be adequate for assessing bipolar disorder in children. They hope outcomes from this study, which will follow the participants for five to ten years, will address whether changes should be made to the diagnostic criteria.
The results represent the second in a series of publications from the Course and Outcome of Bipolar Illness in Youths (COBY) study which is a multicenter National Institute of Mental Health-funded study led by Boris Birmaher, M.D., of the University of Pittsburgh, Martin Keller, M.D., of Brown University and Michael Strober, Ph.D., of the University of California at Los Angeles. The study is the largest study to date of pediatric bipolar disorder and the first prospective naturalistic study of children and adolescents with bipolar spectrum disorders. The first published results established the characteristics and short-term outcomes of the disease.
Co-authors of the study include: Dr. Birmaher, Mary Kay Gill, M.S.N., Laurel Chiapetta, M.S., Neal Ryan M.D., Satish Iyengar, Ph.D., and Jeffery Bridge, Ph.D., of the University of Pittsburgh; Dr. Strober, of the University of California at Los Angeles; and Sylvia Valeri, Ph.D., Henrietta Leonard, M.D., Jeffrey Hunt, M.D., and Dr. Keller, of Brown University.
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