At baseline (Visit 1), subjects whose screening evaluations continue to meet all inclusion/exclusion criteria may enter the study and be randomized. These evaluations will include repeating the Clinical Global Impression modified for bipolar illness (CGI-BP) and the Clinical Global Improvement Scale for anxiety symptoms (CGI-S) to ensure the subject continues to have no more than moderately severe bipolar affective symptoms and at least moderately severe anxiety symptoms. Baseline ratings will include: the Sheehan Panic Anxiety Scale-Clinician Rated (SPAS-C); the Hamilton Anxiety Scale (HAM-A) to assess anxiety symptoms; the Young Mania Rating Scale (YMRS) to assess manic symptoms; and the Inventory for Depressive Symptoms (IDS) (long form) to assess depressive symptoms. Subjects will also be evaluated with the CGI-BP, and the Sheehan Disability Scale (SDS). The Panic-Agoraphobic Spectrum-Self-Report (PAS-SR) will be used to assess the lifetime presence of core and related features of panic disorder. (Subjects who score > 35 on the PAS-SR will be classified a-priori as having panic spectrum symptoms [PSS]). The Family Impact Scale (FIS) will be administered. The Abnormal Involuntary Movement Scale (AIMS), Simpson Angus Scale (SAS), and Barnes Akathisia Rating Scale (BARS) will be administered to assess for extrapyramidal symptoms. Blood pressure, pulse, height, and weight, will be measured. Study medication will be dispensed by the Physician Investigator in the form of 0.5 mg capsules. The dose range of risperidone will be 0.5 to 4 mg/day.