Basics of Criminal Law for Psychologists

Psychological testimony about competency and sanity issues have been used in criminal law cases since psychologists have been accepted as expert witnesses. Testimony at sentencing is also used to mitigate the sentence on guidelines, especially in Capital cases. More recently testimony in the guilt phase using evidence of how mental illness issues impacted someone’s state of mind at the time of an event has been admitted such as Battered Woman Syndrome.  The legal history of the laws governing our testimony will be described. We will discuss assessment of these two areas including protocols for conducting evaluations while clients are being held in jail. Attention will be paid to protecting client’s due process rights including care not to violate their right to remain silent.

Learning Objectives:

Participants will:

  1. Be able to cite the major laws permitting psychological testimony in criminal cases.
  2. Learn the common protocol for a criminal sanity evaluation.
  3. Understand the difference between competency and sanity evaluations.
  4. Review battered woman syndrome and its impact on someone’s state of mind.


Shapiro, D. & Walker, L. (2019). Forensic practice for the mental health clinician. New York: TPI

Walker, L.E., Shapiro, D.L. & Akl, S. (2020). Introduction to forensic psychology: Clinical & Social Perspectives. Second Ed. New York:Springer Nature