Exploring Settled Insanity Through the Lens of Legal and Mental Health Professionals

Date of Award

Spring 6-12-2026

Document Type

Doctoral Research Paper

Degree Name

Psy.D. in Clinical Psychology

Organizational Unit

Graduate School of Professional Psychology

First Advisor

Lynett Henderson Metzger

Second Advisor

Lavita Nadkarni

Third Advisor

Katherine Hannibal

Copyright Statement / License for Reuse

All Rights Reserved
All Rights Reserved.

Keywords

Settled insanity, Substance-induced psychosis (SIP), Natural psychosis, Criminal responsibility, Expert witnesses

Abstract

This mixed-methods study examined the perspectives of legal and mental health professionals on the concept of settled insanity as distinct from substance-induced psychosis (SIP), which might result from the use of methamphetamine (MA). A total of 64 participants recruited through snowball and random sampling responded to a Qualtrics survey, with 41 participants answering the critical question: “Should settled insanity be recognized as a legal defense?” No significant association was found between profession and response to this question; however, thematic analysis of two additional survey questions (“How do you think the legal system can improve its approach on settled insanity or SIP cases?” and “What do you think is important for expert witnesses to communicate to the court about settled insanity?”) highlighted themes related to improving education and training, having clearer statutory definitions, collaboration with mental health professionals, identifying the role of forensic experts in court testimony, creating transparent methodology, linking findings to functional and legal relevance, and eliminating or restricting the defense. These results provide insight into cross-disciplinary perspectives on settled insanity and SIP, underscore the need for greater clarity, more education, improved assessments, and better shared understanding among professionals who encounter cases involving these concepts. Although the study was limited by a small and demographically homogenous sample, lack of multicultural perspectives, and overrepresentation of psychologists, these results offer a starting point for broader, more diverse research exploring this important potential defense across jurisdictions.

Copyright Date

5-4-2026

Publication Statement

Copyright is held by the author. Permanently suppressed.

Rights Holder

Nicole Faith Leggio

Provenance

Received from Author

File Format

application/pdf

Language

English (eng)

Extent

46 pgs

File Size

1.5 MB

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