Mo. Rev. Stat. § 456.6-601
The capacity required to create, amend, revoke, or add property to a revocable trust, or to direct the actions of the trustee of a revocable trust, is the same as that required to make a will.
(L. 2004 H.B. 1511)
Effective 1-01-05, see § 456.11-1104