A Science Update published by the National Institute of Mental Health (NIMH) entitled “Imaging Studies Help Pinpoint Child Bipolar Circuitry” reports the results of recent brain imaging studies that reveal that “…the brain works differently in youth with bipolar disorder (BD) than in chronically irritable children who are often diagnosed with pediatric BD.”
According to Ellen Leibenluft, M.D., chief of NIMH’s Section on Bipolar Spectrum Disorders, which is conducting the studies, “This suggests that chronically irritable children may suffer from a syndrome distinct from BD and may require different treatments.”
This particular article draws some very useful distinctions among the following three diagnoses:
- Bipolar Disorder (BD): Characterized by classic episodes of mania and/or hypomania and distinct changes in mood along with simultaneous changes in sleep, activity, and thought patterns.
- Severe Mood Dysregulation (SMD): Characterized by chronic irritability without clear-cut manic or hypomanic episodes that are interspersed with periods of normal mood or depression.
- Attention Deficit Hyperactivity Disorder (ADHD): While children with BD or SMD commonly have symptoms characteristic of ADHD, children who have ADHD exclusively do not experience the marked irritability of SMD or alternating periods of mania and depression or mania and normal mood (euthymic).
The article points out that children with SMD seem more prone to developing depression and anxiety rather than bipolar disorder as adults and that SMD is much more common than pediatric BD. In the latest proposed revision of the Statistical Manual of Mental Disorders (DSM-V), SMD is included in the category Temper Dysregulation Disorder with Dysphoria (TDD).
What is most significant about this study is that it highlights the importance of having an accurate diagnosis prior to treatment. In particular, the choice of medications is often quite different if the diagnosis is more likely depression and/or anxiety instead of bipolar.
This study is one of a growing body of literature that is beginning to define psychiatric illnesses by the neuropathology – the actual changes in the brain that cause symptoms, rather than by the symptoms alone. This is profoundly important as the field moves forward – understanding causes and mechanisms of different illnesses will allow us to develop more targeted and effective treatments. These types of studies also help in the battle against stigma toward those suffering with mental illness – these real differences in brain function help people accept the biological basis of mood disorders.