Mental Illness

Mental Illness can be a defense in Minnesota criminal cases in at least two ways.  The M’Naghten insanity defense means that the person accused of a crime at the time of committing the act, the accused was laboring under such a defect of reason, from disease of the mind, as not to know the nature and quality of the act he was doing or, if he did know it, that he did not know what he was doing was wrong.


Many believe that the M’Naghten rule from the 1843 English M’Naghten case, should be updated to better reflect scientific progress in understanding mental illness since then (for example, the update suggested by the Model Penal Code).

Affirmative defense

It is an affirmative defense, meaning the initial burden of asserting the defense and producing some evidence to support it is upon the defense.  Once that is done, however, the burden of proving the defendant was criminally responsible despite mental illness is on the prosecuting attorney.

Excuse defense

It has been characterized as an excuse defense (as opposed to a justification defense).  Thee defendant did it but is excused from criminal responsibility because the act was the product of a diseased mind.

Minnesota has codified the defense in Minnesota Statutes Section 611.026 (2017):

“No person having a mental illness or cognitive impairment so as to be incapable of understanding the proceedings or making a defense shall be tried, sentenced, or punished for any crime; but the person shall not be excused from criminal liability except upon proof that at the time of committing the alleged criminal act the person was laboring under such a defect of reason, from one of these causes, as not to know the nature of the act, or that it was wrong.”

Note the “or cognitive impairment” language and compare with the defense of extreme intoxication (vs. involuntary intoxication.)

Competency often can be restored with medication

The other way mental illness can be formally raised as an issue in a Minnesota criminal case is the Competency of the accused.   Whether a defendant is incompetent to stand trial is a question of whether the he or she lacks the ability to rationally consult with legal counsel or to understand the proceedings or participate in the defense, due to mental illness or deficiency or other disability.

A defendant who is incompetent due to mental illness can generally be resotred to competency with medical treatment with anti-psychotic medications.

Rule 20 of the Minnesota Court Rules of Criminal Procedure

The mental illness defense is addressed in Rule 20.02 of the Minnesota Rules of Criminal Procedure; while mental competency is addressed in Rule 20.01.

Time – symptoms active or in remission?

The time period of the mental illness can be important.  The mental illness defense is concerned with “at the time of committing the act.”  But competency to participate in legal proceedings relates to the defendant at the time of the legal proceedings.

Mental illness symptoms can usually be treated and partially or fully alleviated with psychiatric medications, though it can take weeks for the medications to reach a therapeutic level.  Also, it can take more time for psychiatric physicians to determine an effective medication for a person if one is not already known.

Determining whether a person was not responsible by reason of mental illness can be challenging in part because it requires reconstruction of the past based on available evidence.

When it comes to competency to participate in present and future court proceedings, a person deemed incompetent due to mental illness symptoms can often be restored to competence via medical treatment and medication.

Mental Health issues come up in people’s lives and in criminal cases in other ways as well.  Whether or not an accused person was mentally ill and delusional at the time of the act, met the ancient standard of the M’Naghten rule in current Minnesota law; the person may have also have had diminished capacity.

Diminished capacity defense 

The diminished capacity defense is a partial, negating defense (negating the specific intent element of the state’s case) with the burden on the prosecutor to prove that the defendant acted with the requisite state of mind.

A diminished capacity defense (unless another defense is also successful) would normally mean the person is not-guilty of a more serious specific intent crime (where the result was intended) but still guilty of the basic general intent crime.  An example could be a delusional person who was incapable of intending the resulting death, but intentionally did an unlawful act which led to death (not guilty of premeditated murder, but guilty of murder).

Civil Commitment vs. Criminal Commitment

When a person is “committed” by a court, the person loses their civil rights which are transferred to the custody, care and control of either the head of the prison system, or the head of a state hospital.  If the legal basis for the commitment is mental illness under Minnesota Statutes Chapter 253B, then the result is a Civil Commitment Order.  But if the basis for a commitment is a criminal conviction and sentence under a criminal statute then the result is a Criminal Commitment Order, committing the person to the care and custody of the Commissioner of Corrections.

Civil Commitment process

The civil commitment process can involve medical issues other than mental health, such as chemical dependency, withdrawal-induced psychosis, developmental disability, traumatic brain injury, dementia and other issues.

The court’s civil commitment process does connect with the both the insanity defense and a competency defense in a criminal case in a number of ways.  For example, under Rule 20.01 of the Minnesota Rules of Criminal Procedure,

Subd. 6. Procedure After Competency Proceedings.

(b) (1) Finding of Mental Illness. If the court finds the defendant mentally ill so as to be incapable of understanding the criminal proceedings or participating in the defense, and the defendant is under civil commitment as mentally ill, the court must order the commitment to continue. If the defendant is not under commitment, the court must commence a civil commitment proceeding. The court must supervise the commitment as provided in Rule 20.01, subd. 7.

And, under Rule 20.02,

Subd. 8. Effect of Not Guilty by Reason of Mental Illness or Deficiency.

(1) Mental Illness. When a defendant is found not guilty by reason of mental illness, and the defendant is under civil commitment as mentally ill, the court must order the commitment to continue. If the defendant is not under commitment, the court must commence a civil commitment proceeding and order the defendant to be detained in a state hospital or other facility pending completion of the proceedings. In felony and gross misdemeanor cases, the court must supervise the commitment as provided in Rule 20.02, subd. 8(4).

The Rule 20 Examination


In Minnesota, when the defendant, defense counsel, the prosecutor, or the judge believes mental health is an issue, the court may order a Rule 20 examination of the defendant.

The Rule 20 examination is a psychological or psychiatric assessment (performed by a psychologist or psychiatrist) to develop an expert opinion on Competency to participate under Rule 20.01 or on a Mental Illness (M’Naghten) defense under Rule 20.02.

The court will appoint a Rule 20 Examiner who is the court’s expert.

The defense has the option of retaining another expert to develop an independent expert opinion on either or both of those issues.  Eventually the court (judge) may conduct a hearing and rule on Competency or make initial determinations on a 20.02 mental illness defense which may ultimately go to a jury.

The most common major mental illnesses are mood disorders (e.g., bipolar disorder) and thought disorders (e.g., schizophrenia).

Mental health issues can also influence a court’s sentence.

Social stigma

A popular view, fueled by entertaining stories in movies and television, is that people with mental health issues are dangerous, and that they are likely to use their medical problem to escape criminal responsibility.  In reality, however, people with mental health diagnoses are no more likely to perpetrators of crime than anyone else, but sometimes can be more vulnerable to criminal victimization.  And, for several reasons, people with mental health diagnoses tend to be reluctant and often refuse to assert mental illness defenses even when they appear obvious to others.

Gallagher’s experience with Mental Health issues

Thomas Gallagher, Minneapolis Criminal Defense Attorney
Thomas Gallagher, Minneapolis Criminal Defense Attorney

Thomas Gallagher completed his undergraduate degree major at one of the best Psychology Departments, at the University of Minnesota.  This included coursework in Abnormal Psychology, Experimental Psychology, Behavioral and Cognitive Psychology, Social Psychology, Perception, Linguistics, Developmental (Child) Psychology, Statistics, and Industrial Psychology.

Question?  Call Minneapolis Defense Lawyer Thomas Gallagher at 612 333-1500

Gallagher also gained volunteer and work experience with Youth Emergency Service Hotline and Referral, as a Sociology Research Assistant on a Gender and Sentencing Study, as a Teacher-Therapist with a Minneapolis Children’s Hospital summer program for Autistic Children, and an intern for a major foundation studying non-profit Grantee Evaluation.

Since then, Gallagher has been a life-learner and student of Psychology, as well as Psychology and the Law.  As a lawyer, he devoted part of his practice for 13 years as a court-appointed lawyer in Hennepin County defending persons under Petition for Civil Commitment as Mentally Ill or Chemically Dependent.  During that time, he visited every psychiatric hospital ward and detox center in the Twin Cities, and many beyond.  Gallagher still uses the latest version of The Diagnostic and Statistical Manual of Mental Disorders (DSM), published by the American Psychiatric Association (APA), as an aid in understanding cases and best representing clients.