These medicines differ in the types of bipolar symptoms they treat. Depakote and Tegretol, for example, tend to be more effective in treating mania than depressive symptoms, while Lamictal appears to have stronger antidepressants than antimanic effects. Lamictal also is used more often to prevent future episodes (rather than treat current episodes). Depakote and Tegretol are used to treat acute episodes more than as preventative treatments. Other anticonvulsants are less well-established for treating mood symptoms in bipolar disorder. Some — such as Neurontin, Lyrica, or Topamax — also use “off label” for other types of problems sleep, pain management, anxiety, or weight loss. Each anticonvulsant acts on the brain slightly differently, so your experience may differ depending on the drug you take. In general, however, these drugs are at maximal effectiveness after taking them for several weeks.
Ref. https://www.webmd.com/bipolar-disorder/guide/anticonvulsant-medication