Mental Health and the Death Penalty

Mental Health and the Death Penalty

The defendant's state of mind is often an issue in death penalty cases because the defendant's mental health affects his or her culpability for the crime, ability to assist counsel, and ability to understand the connection between the crime and the punishment imposed. These are all important considerations in ensuring that the defendant receives a fair trial and determining the appropriate punishment. Different mental disorders can affect a defendant's case in different ways. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, a resource widely used by mental health professionals, defines "mental disorder" as

a clinically significant behavioral or psychological syndrome or pattern that occurs in an individual and that is associated with present distress (e.g., a painful symptom) or disability (i.e., impairment in one or more important areas of functioning) or with a significantly increased risk of suffering, death, pain, disability, or an important loss of freedom.

The legal system separates three types of mental disorders: intellectual disability, mental illness, and insanity. All may play a role in a defendant's case, but they are distinct conditions that are handled differently by the legal system because they affect an individual's reasoning, and therefore culpability, differently.

Intellectual Disability

Intellectual disability is characterized by "significant limitations both in intellectual functioning and in adaptive behavior, which covers many everyday social and practical skills. This disability originates before the age of 18." (Source: The American Association for Intellectual and Developmental Disabilities, 2010) The United States Supreme Court held in Atkins v. Virginia (2002) that individuals with intellectual disabilities cannot be executed because they are categorically less culpable than other criminals. Similar reasoning was used when the Court later held that executing juveniles was unconstitutional. Click here to read more about Intellectual Disabilities and the Death Penalty.

Mental Illness

Mental illness is defined by the National Alliance on Mental Illness as a medical condition "that disrupt[s] a person's thinking, feeling, mood, ability to relate to others and daily functioning." It can include diagnoses such as schizophrenia, depression, or bipolar disorder. Having a mental illness does not exempt an inmate from the death penalty, but it can be presented as a mitigating factor during the sentencing phase of a capital trial.


Insanity roughly corresponds to a severe form of mental illness in which the individuals afflicted are so out of touch with reality that they do not know right from wrong and cannot understand their punishment or the purpose of it. Insanity can affect a capital case in three ways:

  1. If a defendant was insane at the time of the crime, he or she can be found not guilty by reason of insanity.
  2. An insane defendant may also be found not competent to stand trial. In such a case, the court would suspend the proceedings until the defendant regains competency, at which point the trial can resume.
  3. A death-sentenced inmate can be incompetent to be executed.

The Supreme Court held in Ford v. Wainwright (1986) that executing the insane is unconstitutional. Because an insane inmate does not understand the purpose of his or her punishment, executing such a person has no retributive or deterrent effect. However, if an inmate's mental competency has been restored, he or she can then be executed.  Click here to read more about Mental Illness and the Death Penalty.