What constitutes an affirmative defense according to Texas Penal Code?

An affirmative defense according to the Texas Penal Code is a legal justification used by a defendant that, if proved, can negate criminal liability. Insanity is a prominent example of an affirmative defense. When a defendant raises the insanity defense, they are asserting that due to a severe mental disease or defect, they were unable to appreciate the nature of their actions or understand that those actions were wrong at the time the offense was committed. This defense is based on the premise that moral culpability is absent when a person's mental state prevents them from grasping the consequences of their behavior.

Other examples of affirmative defenses, while critical in various contexts, do not fit the specific criteria established for insanity. Self-defense, duress, and intoxication can provide justifications or excuses in certain legal situations, but insanity uniquely addresses the mental capacity of the individuals involved at the time of the offense, which is why it constitutes a bona fide affirmative defense in the eyes of Texas law.