What is the duty of an attorney to obtain a psychiatric examination in a personal injury case?

As was said in People v. Frierson (1979) 25 Cal.3d 142, 160-161, 158 Cal.Rptr. 281, 291, 599 P.2d 587, 597, ". . . to render reasonably competent assistance, an attorney bears certain basic responsibilities, including the investigation of available defenses and, in an appropriate case, the obtaining of a psychiatric examination."