In GBMI cases, what burden of proof does the defendant carry to prove mental illness?

• A. The prosecution must prove guilt beyond a reasonable doubt.
• B. The defendant must prove their mental illness by a preponderance of the evidence.
• C. Mental illness evidence must be proven by clear and convincing evidence.
• D. There is no burden of proof required for mental illness.

Answer: (B)

In a Guilty But Mentally Ill (GBMI) case, the defendant must prove that they were mentally ill at the time of the offense by a preponderance of the evidence. That means it’s more likely than not that the mental illness existed when the crime was committed. This standard is lower than proving guilt beyond a reasonable doubt, which the prosecution must do for the crime itself. The GBMI verdict allows a finding of guilt for the offense while acknowledging the defendant’s mental illness, which can affect sentencing and treatment decisions rather than exonerating innocence. Clear and convincing evidence is too strong a standard here, and there is indeed a burden on the defendant to show mental illness under this framework.