What is the mental health defense and the brain damage defense?

^[8] We have previously clarified that these are "two separate but complementary defense strategies" available at mitigation. Elmore v. Sinclair, 799 F.3d 1238, 1250 (9th Cir. 2015). The mental health defense "refers to the presentation of mitigating factors related to [Demetrulias's] possible mental disorders," including physical abuse and neuropsychological impairment. Id. The brain damage defense "refers to mitigating factors related to [Demetrulias's] physical brain damage from prior head injuries" and exposure to toxic agents. Id.