Mental states that determine the degree of guilt or culpability in criminal law are generally classified from highest (most worthy of blame or punishment) to lowest as: (1) intentional; (2) knowing; (3) reckless; and (4) criminal negligence.

A person acts with criminal negligence, or is criminally negligent, with respect to circumstances surrounding his conduct or the result of his conduct when he ought to be aware of a substantial and unjustifiable risk that the circumstances exist or the result will occur. The risk must be of such a nature and degree that the failure to perceive it constitutes a gross deviation from the standard of care that an ordinary person would exercise under all of the circumstances, as viewed from the accused person’s standpoint at the time of the alleged criminal negligence.

Criminal offenses or crimes often specify the culpable mental state the prosecution is required to prove to convict a defendant of the offense. These culpable mental states are generally defined in the relevant state or federal statutes—usually in the penal or criminal code.

In Maryland, as in many jurisdictions, the mental state of an individual at the time of committing a crime is a critical factor in determining their degree of guilt or culpability. Maryland law recognizes various levels of mental states that can affect criminal liability, including intentional, knowing, reckless, and criminal negligence. Intentional acts are those committed with a purpose to cause a specific result, while knowing acts are those where the individual is aware that their conduct will likely cause a certain outcome. Reckless behavior involves conscious disregard of a substantial and unjustifiable risk, and criminal negligence refers to a failure to perceive such a risk, representing a gross deviation from the standard of care an ordinary person would exercise. These mental states are defined within Maryland's criminal statutes, and the prosecution must prove the requisite mental state to secure a conviction for many offenses. The specific definitions and applications of these mental states are detailed in the Maryland Criminal Law Code and are essential for determining the appropriate level of punishment for a crime.