How reliable are forensic evaluations of legal sanity?

Abstract

When different clinicians evaluate the same criminal defendant's legal sanity, do they reach the same conclusion? Because Hawaii law requires multiple, independent evaluations when questions about legal sanity arise, Hawaii allows for the first contemporary study of the reliability of legal sanity opinions in routine practice in the United States. We examined 483 evaluation reports, addressing 165 criminal defendants, in which up to three forensic psychiatrists or psychologists offered independent opinions on a defendant's legal sanity. Evaluators reached unanimous agreement regarding legal sanity in only 55.1% of cases. Evaluators tended to disagree more often when a defendant was under the influence of drugs or alcohol at the time of the offense. But evaluators tended to agree more often when they agreed about diagnosing a psychotic disorder, or when the defendant had been psychiatrically hospitalized shortly before the offense. In court, judges followed the majority opinion among evaluators in 91% of cases. But when judges disagreed with the majority opinion, they usually did so to find defendants legally sane, rather than insane. Overall, this study indicates that reliability among practicing forensic evaluators addressing legal sanity may be poorer than the field has tended to assume. Although agreement appears more likely in some cases than others, the frequent disagreements suggest a need for improved training and practice.

Insanity findings and evaluation practices: A state‐wide review of court‐ordered reports

“…Further, the rate of insanity opinions observed in the present study is based on 1 year of reports, whereas the earlier study presented data spanning 10 years (which featured minor year‐to‐year fluctuations). The current 17% rate ultimately falls within the range of other reported base rates of insanity findings, which seem to vary considerably by jurisdiction (Guarnera & Murrie, ), exceeding 30% in some states (Gowensmith et al, ), but trending towards 10–15% in most jurisdictions (e.g., Cochrane et al, ; Warren et al, ).…”

“…Thus, Hawaii provides an ideal "natural experiment" for studying field reliability (Gowensmith, Murrie, & Boccaccini, 2013). In this context, the base rate of insanity findings was around 35%, and agreement among all three evaluators occurred in 55% of cases (κ = 0.56; Gowensmith et al, 2013).…”

Forensic Assessment via Videoconferencing: Issues and Practice Considerations

“…In some instances, the disagreement between or among experts from both different and similar professional circles could, in part, be due to the knowledge and awareness about the quality of forensic mental health evaluations. Indeed, it is widely asserted that forensic evaluations are fraught with substantial limitations, including incomplete information, missing data, and failure to link clinical opinion to the psycholegal issue (Fuger, Acklin, Nguyen, Ignacio, & Gowensmith, 2014;Gowensmith, Murrie, & Boccaccini, 2013;Nguyen, Acklin, Fuger, Gowensmith, & Ignacio, 2011). Some scholars have termed forensic evaluations produced for the courts as "mediocre" to reflect the ubiquity and the alarming rate of the problem (e.g., see Fuger et al, 2014).…”

Criminal responsibility: Meta‐analysis and study space

“…The court acquits anywhere from 1% to 50% of insanity defendants, although this base rate typically falls around 25% of cases where an insanity plea is entered (McGinley & Pasewark, ; Steadman et al, ). Despite the usual congruence between evaluator and court opinions noted earlier, the courts do not always agree with evaluators' opinions, and sometimes disagree with a group of evaluators' majority opinion on a given case (Gowensmith, Murrie, & Boccaccini, ).…”