The defendant should be interviewed as soon as possible after the offense. However, defendants are often evaluated for sanity many months after the offense. Early evaluation reduces the likelihood that the defendant will have been coached about the legal criteria for insanity. Furthermore, as time passes, defendants may change their account of the offense because of unconscious distortion or attempts to malinger insanity.
At the outset of the interview, the defendant must be informed of the purpose of the evaluation, who will receive a report of the evaluation, and the lack of confidentiality. A careful psychiatric history should be obtained from the defendant, including inquiry into the nature of hallucinations, delusions, and past treatment efforts. The psychiatrist should request a detailed account of the crime by the defendant. It is helpful to have the defendant give a step-by-step account of his actions beginning 1 to 2 days before the offense. The account should include details on psychiatric symptoms, medication adherence, and use of intoxicants.
Formation of the insanity defense opinion
Opinion formation is the most challenging aspect of the insanity defense evaluation. The underlying reasons for the opinion must be clearly explained. Having a logical rationale for the opinion is critical. Before formulating the opinion, the psychiatrist should strive for a detailed understanding of the defendant’s thinking and behavior before, during, and after the offense. It is important to consider evidence of mental illness (during the evaluation, in the past, and at the time of the offense), possible psychotic and nonpsychotic motives for the offense, and the defendant’s criminal history and personality type.
The psychiatrist should assess whether the defendant’s inability to know the wrongfulness or refrain from the act was the result of mental illness or other factors, such as voluntary intoxication or rage. It may be helpful to conceptualize insanity opinion formation as consisting of a 3-step process:
• First, the question of whether the defendant suffered from a mental disease or defect at the time of the offense must be answered.
• Next, capacity evidence must be addressed—that is, knowledge of wrongfulness of the offense at the time in question.
• Finally, the issue of causation must be addressed—what was the relationship between the defendant’s mental disease and criminal behavior?
Mental disease evidence
Virtually all insanity standards require the presence of a “mental disease or defect” at the time of the offense. Mental disease or defect is a legal term and is not defined in DSM. However, the American Psychiatric Association Position Statement on the Insanity Defense from 1982 does provide some guidance: “Another major consideration in articulating standards for the insanity defense is the definition of mental disease or defect. . . . [M]ental disorders leading to exculpation must be serious. Such disorders should usually be of the severity (if not always of the quality) of conditions that psychiatrists diagnose as psychoses.”1
In a study of 5175 sanity evaluations, findings of insanity by expert opinion were significantly associated with the defendant having psychosis and having had psychiatric hospitalizations.7 Similarly, in a study of 8138 defendants who pleaded insanity, those with a major mental illness and who had had psychiatric hospitalizations (suggesting more severe illness) had higher rates of acquittal by reason of insanity.8 Studies of persons who were found NGRI indicate that a psychotic level of illness is usually required.9-11 Most courts have held that diagnoses such as schizophrenia, major depressive disorder, and bipolar disorder qualify as a mental disease for the purpose of insanity.
Diagnoses such as personality disorders, paraphilias, and voluntary substance intoxication do not usually qualify. Although some state statutes provide guidance on which disorders are excluded, the final decision rests with the trier of fact. The concept of mental disease as used in legal standards for insanity is “generally construed to refer to a disorder of fixed or prolonged nature in contrast to any transitory emotional state.”12 Thus, temporary displays of rage or aggression unassociated with a major mental disorder are unlikely to qualify as mental disease. The term “mental defect” most commonly refers to mental retardation or some developmentally acquired disorder of intellect. The finding of a mental defect typically requires intellectual impairment in the range of at least mild mental retardation.
Capacity evidence
All US insanity standards (with the exception of the New Hampshire Doctrine) address the defendant’s knowledge of wrongfulness of the offense at the time of the act. Table 2 presents a list of behavioral evidence that warrants consideration by the psychiatrist when evaluating a defendant’s capacity to recognize the wrongfulness of his criminal act.
When evaluating knowledge of wrongfulness, the psychiatrist should carefully analyze the defendant’s behaviors, statements, and motives. For example, hiding evidence, lying about the offense, and fleeing from the police all suggest that the defendant knew that his behavior was legally wrong. In contrast, committing a crime with no rational motive, making no effort to avoid detection, and making no effort to flee may suggest a lack of knowledge of wrongfulness. As noted, the defendant’s statements during or after the offense often provide critical insight into the defendant’s knowledge of wrongfulness. Statements made by the defendant months later that he knew the act was wrong are helpful, but care must be used to determine whether the defendant can accurately recall his thinking at the time of the crime.
