In most jurisdictions I've observed recently, the "legal" criteria are:

1. The person is capable of understanding the charges.
2. The person is competent to assist in his/her own defense.

Beyond those two, you can be loony as suits you, and cannot use "insanity" to avoid going to trial.

In some, but not all jurisdictions, the court may consider things like "ability to recognize right vs wrong" in determining "degree of guilt" (culpability) but except in unusual circumstances it's my impression this is applied more often to sentencing than to determination of "guilt."

Of course I only know as much as the news tells me.

John