Competency to Stand Trial and Criminal Responsibility
Legal standards
Competency to stand trial comes from Dusky v. United States: the defendant must have sufficient present ability to consult with counsel with a reasonable degree of rational understanding and a factual and rational understanding of the proceedings. It is functional, context-specific, and presumed unless questioned. Criminal responsibility addresses mental state at the time of the offense; common tests include M'Naghten (cognitive), the MPC/ALI standard (volitional or cognitive), and federal law after the Insanity Defense Reform Act. Jackson v. Indiana limits indefinite commitment of incompetent defendants; Sell v. United States governs involuntary medication for restoration.
Instruments
MacCAT-CA, ECST-R, GCCT, and CAST*MR structure competency data; they do not replace clinical judgment.
Worked example
A defendant knows the charges but believes his attorney is a demon. He cannot rationally assist. The evaluator should address both Dusky prongs, not just factual knowledge. Reasoning: factual understanding alone is insufficient; rational understanding and ability to consult are separate.
Traps
Equating psychosis with incompetence; using a competency evaluation to opine on insanity; ignoring amnesia; assuming medication restoration is always permissible; conflating competency and responsibility.