Also known as: Durham's rule · product test · Durham test
Written by attorneys · grounded in primary & secondary sources — see below
A test for the insanity defense that requires acquittal when the charged offense was the product of a mental disease or defect. The offense qualifies as a product of the condition when the defendant would not have committed the crime but for the mental disease or defect.
Carla, an emergency room nurse at Riverside Hospital, suddenly attacked a pharmaceutical representative with trauma shears. Defense experts testified that Carla suffered from severe postpartum psychosis and that but for this psychosis she would not have attacked. In a jurisdiction applying the Durham rule the jury must acquit because the assault resulted from her mental disease.
Clifford, a control-room technician at Park Energy's nuclear facility, bypassed three redundant safety interlocks on the reactor cooling system while experiencing active paranoid delusions that federal agents had installed hidden shutdown mechanisms. He immediately told investigators he had acted solely because he believed the interlocks were part of a government blackout conspiracy. Under the Durham rule the court must determine whether the bypass would have occurred but for the mental disease.
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The defendant must show that the charged offense resulted from a mental disease or defect. This requires proof that the defendant would not have committed the crime but for the mental condition.
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The Durham rule focuses solely on causation rather than on cognitive or volitional capacity. It is broader because it asks only whether the offense was the product of mental disease or defect.
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The rule was criticized as too broad because it permitted acquittals whenever a mental disease existed and supplied a but-for cause without further limits on the definition of mental disease or defect.
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Yes. When facts show the defendant would have committed the offense even without the mental disease, the but-for link is broken and acquittal is not required under the Durham rule.
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…(adopting modern “product” test). But see United States v. Brawner , 471 F.2d 969 (D.C.Cir.1972) (abandoning Durham product test and adopting ALI-MPC test).[^disA-2] In Colorado, the test of criminal responsibility, which has been codified in section 16-8-101(1), is the “right from wrong” prong of the test announced…