Invega (paliperidone), a second generation antipsychotic (SGA), is a psychotropic agent belonging to the chemical class of benzisoxazole derivatives. Invega is approved by the FDA for the treatment of schizophrenia in adults. Initial data suggest a promising role for Invega in the treatment of bipolar disorder with minimal adverse events of weight gain. We propose to study the safety and efficacy of Invega therapy in children and adolescents with Bipolar I, Bipolar II, and Bipolar Spectrum Disorder. The study results will be used to generate hypotheses for a larger, randomized, controlled clinical trial with explicit hypotheses and sufficient statistical power.