A more thorough explanation:

The Durham test is a legal test used in some places to determine if a defendant can claim insanity as a defense. It is named after the case Durham v. United States.

According to the Durham test, a defendant can claim insanity if their criminal behavior was caused by a mental illness or defect. This means that the mental illness or defect was the main reason for the criminal behavior. Unlike the M'Naghten test, which is another test used to determine insanity, the Durham test does not consider whether the defendant knew that their actions were wrong.

For example, if someone with a mental illness commits a crime because of their illness, they may be able to use the Durham test to claim insanity as a defense.

Another example could be if someone with a mental defect commits a crime because they were not able to understand the consequences of their actions.

These examples illustrate how the Durham test is used to determine if a defendant can claim insanity as a defense based on their mental illness or defect.