<P>Of critical importance to making the diagnosis of childhood bipolar disorder is being aware of its likelihood and alert to its major characteristics. Childhood-onset bipolar illness was prevalent even some 20 years ago but was largely unrecognized. Twenty-six percent of the adult outpatients in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) reported that their age of onset of illness was before age 13, and 15% of the adults in the Bipolar Collaborative Network (BCN) also had childhood onset. Strikingly, those in the BCN with illness onsets before age 13 were not treated with medicines for either depression or mania until an average of more than 15 years after illness onset. In those with adolescent onsets (ages 13 to 18), this delay to onset of first treatment decreased to an average of 10 years but was still markedly longer than those with adult onsets. </P> <H4>ABOUT THE AUTHORS</H4> <P>Dr. Post is professor of psychiatry, Pennsylvania State University School of Medicine, Hershey, PA, and formerly was a special volunteer, Mood and Anxiety Disorders Program, National Institute of Mental Health, Bethesda, MD. Dr. Findling is director, Child and Adolescent Psychiatry, University Hospitals, Cleveland, OH, and professor, Psychiatry and Pediatrics, Case-Western Reserve University, Cleveland. Dr. Kowatch is professor of psychiatry and pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati Medical Center, Department of Psychiatry, Cincinnati, OH. </P> <P>Address reprint requests to: Robert M. Post, MD, Bldg. 10, Room 3S239, 10 Center Drive MSC-1272, Bethesda, MD 20892-1272; or e-mail <a href="mailto:postr@mail.nih.gov">postr@mail.nih.gov</a>. </P> <P>Dr. Post disclosed relevant financial relationships with Abbott Laboratories, AstraZeneca, GlaxoSmithKline, Janssen, Novartis, Pfizer, Shire, UBC, and Eli Lilly. Dr. Kowatch disclosed relevant financial relationships with Abbott Laboratories, AstraZeneca, Bristol-Myers Squibb, Cephalon, Creative Educational Concepts, Eli Lilly, GlaxoSmithKline, Janssen, and Otsuka. Dr. Findling disclosed relevant financial relationships with Abbott Laboratories, AstraZeneca, Bristol-Myers Squibb, Celltech-Medeva, Eli Lilly, Forest, GlaxoSmithKline, Johnson & Johnson, New River, Novartis, Otsuka, Pfizer, Sanofi-Aventis, Shire, Solvay, and Wyeth.</P>