Mental Health and Fitness for Trial in Queensland
Criminal Procedure — 2026-08-06 — by Sacha Sarah Smith, Civic Law
If you have a mental health condition and you are facing criminal charges, it can affect your case in three different ways — as a defence, as a question of whether you can go through the court process at all, and as a factor the court weighs at sentencing.
A mental health condition — diagnosed or not — changes the way a criminal case runs. Sometimes the condition was there at the time of the offence. Sometimes the stress of the charge has made it worse. Either way, Queensland law treats it as something the court needs to know about.
Mental health can affect a criminal case in three ways. It can be a complete defence — meaning a person is not held criminally responsible for what happened. It can raise the question of whether they are fit to go through the court process at all. And even where it is neither of those, it can change what happens at <a href="/sentencing-explained">sentencing</a>. The way it matters depends on the nature of the condition, the seriousness of the charge, and how and when the issue is raised.
The Unsound Mind Defence
Under section 27 of the <em>Criminal Code 1899</em> (Qld), you are not criminally responsible for what you did if, at the time, a mental disease or natural mental infirmity deprived you of the capacity to do any one of three things:
<strong>Understand what you were doing.</strong> You did not know the nature of the act — you did not understand what was happening.
<strong>Control your actions.</strong> You knew what you were doing but your condition made it impossible for you to stop.
<strong>Know that you ought not to do it.</strong> You did not understand that what you were doing was wrong.
If any one of those applies, the law says you were of "unsound mind" and you are not held responsible for the offence. That is a high threshold. A diagnosis alone does not meet it. Anxiety, depression, PTSD, and most personality disorders do not usually reach the point where they deprive someone of the capacity to understand, control, or know right from wrong. The conditions that most commonly do are psychotic illnesses — schizophrenia, schizoaffective disorder, severe bipolar episodes with…
One thing that does not count: voluntary intoxication. If you were affected by alcohol or drugs you took intentionally, section 28 of the <em>Criminal Code</em> says the unsound mind defence does not apply — even if the combination of the substance and a pre-existing condition contributed to what happened. That rule catches a common situation: someone with a mental health condition who was also using substances at the time.
What "Unfit for Trial" Means
Fitness for trial is a different question from unsound mind. Unsound mind asks what your mental state was at the time of the offence. Fitness for trial asks what your mental state is now — whether you can participate in the court process in a meaningful way.
A person is unfit for trial if their current mental condition means they cannot follow the proceedings, instruct their lawyer, or understand the case well enough to respond to it. You might have been perfectly capable of understanding your actions when the offence happened, but your condition has since deteriorated to the point where you cannot go through a hearing. Or the condition was always there, but its effect on your ability to participate is the question, not its effect on how much you…
Fitness for trial can also be temporary. If your condition is treatable and your treating team expects improvement, the court process can be paused while you receive treatment — and resumed once you are well enough to participate.
How These Questions Get Before a Court
For indictable offences — the more serious charges — the question goes to the Mental Health Court, which sits in Brisbane and deals exclusively with these issues. A reference to the Mental Health Court can be made by you, by your lawyer, or by the Director of Public Prosecutions under section 110 of the <em>Mental Health Act 2016</em> (Qld). The chief psychiatrist can also refer the matter after a psychiatrist report has been prepared.