RT Journal Article SR Electronic T1 Assessing Undue Influence JF Journal of the American Academy of Psychiatry and the Law Online JO J Am Acad Psychiatry Law FD American Academy of Psychiatry and the Law SP 344 OP 351 VO 44 IS 3 A1 Plotkin, Daniel A. A1 Spar, James E. A1 Horwitz, Howard L. YR 2016 UL http://jaapl.org/content/44/3/344.abstract AB A claim of undue influence (UI) often figures prominently in will and trust contests and in other legal matters. Mental health professionals (MHPs) are frequently asked to provide expert opinions on UI, but the task is challenging, because of the lack of a clear definition of UI, and conflicting and contradictory recommendations in the literature on the specific conduct of the MHP in rendering opinions on UI. Recently, however, a California statutory scheme on UI applicable in will, trust, conservatorship, and financial elder abuse cases was adopted, bringing greater clarity to the meaning of the construct. The clarification provides an opportunity to review the concern, and to recommend a set of principles to guide MHPs in the role of expert in such litigation.