Treatment options to relieve the diverse symptoms encountered in patients with bipolar disorders include not only mood stabilizers, but also anxiolytics, new anticonvulsants, antidepressants, and antipsychotics. These agents have widely varying mechanisms of action, which could contribute to the heterogeneity of clinical effects seen in practice. Several of these medications, especially those with anticonvulsant effects, enhance gamma-aminobutyric acid (GABA) inhibitory neurotransmission and/or attenuate glutamate excitatory neurotransmission. We review the efficacy and tolerability of these diverse treatment options in bipolar disorders and explore possible relationships between clinical effects and GABAergic and antiglutamatergic mechanisms of action.