Bipolar disorder (BPD) shows up in around one percent of all children. The disorder is marked by extreme mood swings ranging from mania (high energy and euphoria) to depression. BPD also produces flashes of anger and even aggression. Irritability and aggressiveness are also common to autism. When two conditions share similar symptoms, the chance of a misdiagnosis increases. For parents trying to find the best treatment for their child, understanding whether they are dealing with one or two disorders is vital. Two conditions which commonly occur together are referred to as comorbid. Since the comorbid conditions share some symptoms it is not unusual for kids to be diagnosed with only one of the two. Frequently, children have been diagnosed with bipolar disorder alone without realizing that the child also has an autism-spectrum disorder. Research suggests that up to 30 percent of kids who are diagnosed with bipolar disorder could also be suffering with autism. A trio of studies sought to untangle the two conditions. In the first, 155 kids (6-17 years old) with bipolar disorder and 487 close relations were interviewed. Through close examination expert clinicians discovered that 47 kids (about 30 percent) with diagnosed bipolar disorder also had autism. The researchers looked for any signs that would indicate whether a child had one or both conditions. One clue seemed to be the age of diagnosis. Kids who were found to actually have both bipolar disorder and autism were noted to have been diagnosed with their bipolar disorder at earlier ages compared to children with BPD alone. Another clue they discovered is that kids with both disorders tend to have more intense symptoms of over-estimated self or grandiosity. These kids were on the extreme end of thinking they possessed special abilities, powers or holding themselves in unreasonably high self-regard. The research team also took a look at family history in order to find clues to diagnosing autism and BPD as comorbid. They compared 162 kids with ADHD and 511 of their close relatives, and a control group of 136 healthy children with 411 of their first-degree relations. What they found was that kids with BPD have a greater likelihood of psychosis within their close family compared to either those within the control group or kids with ADHD. Experts say that this helps to clarify when a child truly suffers from the two similar disorders and when they have been misdiagnosed with bipolar disorder alone because the signs of autism have been misconstrued as BPD. The full study findings can be found in the Journal of Clinical Psychiatry.