If benzos are addictive, why isn't divalproex sodium; both affect gaba?

They act differently: and the primary effect of valproate is NOT on GABA receptors but on sodium channels, and it's GABA effects are different from benzos in terms of GABA subreceptors. NO drug is addictive. People have underlying predispositions, inherited or acquired, and drugs that can produce physical dependency can trigger addiction in those patients. Depakote and other seizure meds have little/no abuse potential