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Mental Health Expert Witness for Personal Injury Claims

More Than 100 Trials
Deena McMahon, Expert Witness

Deena McMahon, LICSW, MSW, has more than 30 years of experience as a social worker. She is known for handling the “deep end” of the child welfare pool — the extremely difficult cases that can cause lasting harm. She has provided forensic assessments and defended those assessments in court on cases involving:

  • Child abuse
  • Child sexual abuse
  • Trauma
  • Attachment theory
  • Adoption dynamics
  • Indian Child Welfare Act (ICWA) cases
  • Fatality, including homicide
  • Students’ rights to services under the ADA
  • Wrongful death or harm to children in foster care or residential care

With more than 100 trials to her credit, Ms. McMahon is a skilled expert witness.

$166.1 Million Settlement in a Landmark Sexual Abuse Case

Ms. McMahon served as a forensic expert in a case involving approximately 500 Native American claimants in Montana and Washington who were physically and/or sexually abused as children by members of the Pacific Northwest Jesuits. The $166.1 million settlement in the case is one of the largest ever against a religious organization in the U.S. Ms. McMahon interviewed abuse victims and helped the plaintiff’s attorney understand the harm his clients had suffered due to the trauma of sexual abuse.

Ms. McMahon has spoken nationally and internationally on issues of child welfare, child development, brain development and other topics. In addition to her decades of experience in practice, she has established her expertise by training mental health professionals, teachers, school staff, lawyers, judges and others.

Ms. McMahon is available to serve as a mental health expert witness for either the plaintiff or defense team. She can provide consultation, case evaluation, forensic assessments, testimony for deposition and trial, report writing and more.

If you are seeking an articulate and effective mental health expert witness, please contact Deena McMahon and McMahon Counseling and Consultation Services.


Attorneys who lost cases because I testified for their opponents have hired me on subsequent cases. I consider that  the highest form of professional compliment.

Deena McMahon, MSW, LICSW