If a person is intoxicated through drink or drugs and commits a crime then the intoxication may be to prevent the defendant forming the reasons for crime.
Explanation:
If the defendant claim responsibility on the substance intoxication in a criminal law then it is known as defense of intoxication.
For example if the police takes a blood test to measure the blood alcohol content(BAC) of the driver and then if BAC level is above the limit then it is considered as the evidence of intoxication.
Mistake of fact relates to the person committing illegal act and defence of crime. If the person commits illegal act and tries to escape by claiming ignorance of the law is known as mistake of law.