Causation and Apportionment
Separate pre-existing psychiatric conditions from injury-related harm and other contributing factors using the available medical evidence.
40+ Years in Psychiatry
Clear Psychiatric Opinions That Hold Up to Scrutiny
Board-certified psychiatrist with 40+ years of experience, retained by plaintiff and defense attorneys in emotional distress, PTSD, harassment, and personal injury litigation.
- Board-certified psychiatrist (ABPN), Life Fellow of the APA
- Plaintiff and defense experience in civil litigation
- Causation, apportionment, damages, and prognosis
- Virtual examinations available; fluent in Spanish
Board-Certified (ABPN)
Plaintiff and Defense
Serving California Attorneys
Virtual Exams
Psychiatric Claims Are Won or Lost on Clarity
Emotional distress and psychological injury claims often turn on difficult questions: What is the diagnosis? What caused it? What existed before the alleged event? What does the future prognosis look like?
Dr. Weiss reviews the relevant medical evidence, evaluates the psychiatric issues, and communicates her opinions in language attorneys, judges, and juries can understand.
Evidence-Based Reports
Clear, thorough written opinions supported by psychiatric evaluation, medical records, and a consistent clinical methodology.
Deposition and Trial Testimony
Prepared, composed testimony that communicates complex psychiatric findings with clarity and professionalism.
PSYCHIATRIC EXPERT WITNESS
OBJECTIVE · EVIDENCE-BASED · INDEPENDENT
Objective Opinions Protect Your Case
A psychiatric expert should follow the medical evidence—not simply the position of the retaining party. Dr. Weiss provides neutral, evidence-based analysis. When findings support a position, she explains why. When the evidence raises concerns, counsel can identify them earlier in the case.
01
Independent Analysis
Opinions grounded in the psychiatric and medical evidence.
02
Plaintiff and Defense Experience
Decades of work supporting both sides of civil litigation.
03
Identify Issues Early
Clarify questions involving causation, apportionment, damages, prognosis, and potential areas of challenge.
Trusted Psychiatric Expertise
“Dr. Weiss was responsive, well qualified and always prepared. She understands complex medical issues and has the ability to present her opinions to lay persons, the essence of a good expert.”
— Thomas M. Madruga, Esq.
Meet Dr. Weiss
Meet Dr. Diane J. Weiss, MD, MPH
Dr. Weiss is a board-certified psychiatrist with more than 40 years of experience and decades of work supporting both sides of civil litigation.
She earned her M.D. at Boston University School of Medicine and her M.P.H. at the UCLA School of Public Health, completed her psychiatry residency at UCLA, and serves as a Volunteer Assistant Clinical Professor at the UCLA David Geffen School of Medicine.
She is a Life Fellow of the American Psychiatric Association and maintains a private practice in Beverly Hills.
Dr. Weiss routinely addresses causation, apportionment, damages, and prognosis in emotional distress, PTSD, harassment, discrimination, employment, and personal injury matters. She is fluent in English and Spanish.