Legal Definitions - Durham rule

The Durham rule was a legal standard formerly used in criminal law to determine if a defendant could be found "not guilty by reason of insanity." Under this rule, a person was not considered criminally responsible for an unlawful act if that act was the direct product of a mental disease or defect.

Developed in the 1954 case of Durham v. United States, this test focused on establishing a causal link between a defendant's diagnosed mental condition and their actions. If the criminal act was determined to have resulted directly from the mental illness, the defendant could be excused from criminal responsibility. However, the Durham rule faced significant criticism for being too broad and lacking clear definitions for what constituted a "mental disease or defect" and how to definitively prove an act was its "product." Consequently, it is no longer accepted in any American jurisdiction, having been replaced by more stringent insanity defense standards. It was also sometimes referred to as the "product test."

Here are some examples illustrating how the Durham rule might have been applied:

• Example 1: Delusional Destruction of Property
  A person diagnosed with severe paranoid schizophrenia experiences vivid hallucinations and delusions, believing that a specific public monument is a malevolent entity broadcasting harmful thoughts into their mind. Acting on this delusion, they vandalize the monument, believing it is the only way to silence the perceived threats. Under the Durham rule, their defense would argue that the act of vandalism was a direct product of their severe mental disease (schizophrenia) and its accompanying delusional state, thus excusing them from criminal responsibility.

• Example 2: Psychotic Episode Leading to Assault
  An individual with a history of severe bipolar disorder experiences a manic episode with psychotic features. During this episode, they genuinely believe a stranger on the street is a demonic figure attempting to harm them, despite no objective evidence. In response, they physically assault the stranger. A defense using the Durham rule would contend that the assault was a direct product of their mental disease (bipolar disorder with psychosis), as their perception of reality was severely distorted by their illness at the time of the act.

• Example 3: Dissociative State and Theft
  A person diagnosed with severe dissociative identity disorder (DID) enters an altered state where a different personality, unaware of societal laws or the concept of ownership, takes control. While in this dissociative state, this personality takes items from a store without paying, genuinely believing they are simply "collecting" them. Under the Durham rule, the defense could argue that the theft was a direct product of the mental defect (DID), as the act occurred while a personality state lacking criminal intent or understanding of the act's wrongfulness was dominant, directly resulting from the disorder.