“I’m not seeing clear patterns of distinct periods of being accelerated and talking and moving and thinking with an intensity of mood that just overflows and then goes back to his usual state,” Axelson said. “The intense anger outbursts can happen in kids with bipolar disorder, but they can happen with other mood disorders, or with A.D.H.D. and severe oppositional behavior. He’s only 7 years old. This could be the very early signs of bipolar, and it may not be until two, three, four, five years from now that we’d have a clear idea. That doesn’t mean that he doesn’t need intensive treatment  he really does.” (Joe is currently in treatment at the Western Psychiatric Institute and Clinic, but the right medication has proved elusive.)

It’s possible that a different doctor might have identified Joe as bipolar. In an influential 1995 paper that began the paradigm shift toward bipolar disorder within child psychiatry, Janet Wozniak  the director of the pediatric bipolar-disorder program at Massachusetts General Hospital and co-author of “Is Your Child Bipolar?”  working with the chief of pediatric psychopharmacology, Joseph Biederman, revealed that 16 percent of the children who came to the clinic met the D.S.M. criteria for mania. This was shocking news; it was widely believed until then that mania in children was extremely rare. Wozniak reported that the children’s mania most often took the form of an irritable mood rather than an elevated one, and that the mood was often chronic: the norm, rather than the exception. All but one of the manic children in the study also suffered from A.D.H.D.

Wozniak told me that the discovery of mania in so many of the kids she was treating came as a shock to her too. “It was like I opened up my eyes: Oh, my goodness, these children have bipolar disorder,” she said. “And I realized that what I’d been treating them for hadn’t been working well. I was often treating them for bad A.D.H.D., using different stimulant medicines or higher doses. I was often treating them for their depression and not getting anywhere. In those days, the teaching was that we had a group of medicines that could be used for ‘aggression’ in children. What’s interesting is that these were the anti-manic agents; they were lithium and antiseizure medicines.” In other words, many of the children in Wozniak’s clinic went unrecognized as bipolar, but they were inadvertently being treated for bipolar.

The tricky part, diagnostically, is that out of those seven symptoms, three  distractibility, activity increase and talkativeness  are also symptoms of A.D.H.D. Which means that a severely irritable child who has A.D.H.D. could be, theoretically, only one symptom away from a bipolar diagnosis.

Does it even matter whether or not we call Joe or James bipolar, since the drugs used to treat irritable, aggressive children are often the same as those used for bipolar disorder? Critics of the more widespread use of a pediatric bipolar diagnosis say it does. For one thing, being bipolar makes certain medications extremely risky to use; stimulants can intensify a manic episode, and antidepressants like Zoloft or Prozac can make bipolar patients not just manic but psychotic, even suicidal. In fact, some clinicians say that a number of young patients who become suicidal while on antidepressants  occasioning the “black box” warning currently mandated for drugs like Prozac  in fact suffer from undiagnosed bipolar disorder.

Gabrielle Carlson, the director of child and adolescent psychiatry at the Stony Brook University School of Medicine, has studied childhood mania for many years and says bipolar disorder is uncommon in children under 10, revealing itself in the same discrete episodes of mania and depression that we see in bipolar adults  not in chronic irritability. According to Carlson, a large group of aggressive and explosive children, who in fact are “diagnostically homeless,” are being relabeled as bipolar, which is a development she says is unhelpful both to the children and the field. “Diagnostically it ends up being a very important consideration of what the kid really has,” she told me. “If he really has A.D.H.D. and it’s not mania, then you give him medication for his A.D.H.D. You also give him behavior modification.” One patient she saw that day, who was thought to have bipolar disorder, actually had autism, she said. “If you say, ‘Hey, his problem is bipolar disorder,’ then you’re not going to treat his language disorder, you’re not going to give the social-skills treatment he needs,” she said. Problematic conditions in a child’s home life are also less likely to be addressed if the child’s behavioral issues are attributed to bipolar disorder, Carlson said. “Many people, when they hear bipolar disorder, their brain slams shut.”

Afternoons at the Pittsburgh bipolar clinic are the time when ongoing patients come in for shorter appointments to assess the impact of their medication regimes on their mood and check for side effects. On my visit in March, Axelson’s last appointment of the day was with a pair of bipolar siblings: Phia, 9, and Lucas, 6, both of whom he had been treating for the last year and a half. They were a dynamic and appealing pair, if slightly overcharged; there was constant climbing and prowling in the small office. Phia, who wore a pink sweater, black cords and red wool-lined Crocs, had begun taking lithium just a few weeks before, after two different antipsychotic drugs produced an uncomfortable muscular sensation in her legs called akathesia. Now that she was on lithium and a lower dose of one of the antipsychotics, the akathesia had stopped, and both Phia (a family nickname) and her mother, Marie, agreed she was doing well. On the other hand, Lucas, a vigorous, bullet-headed boy who that day wore camouflage pants, was behaving oddly, Marie said. “Throughout the course of a day, there’s a shift from a whole lot of bravado to limp,” she told Axelson.