This article contains references to sexual assault.
Most people who break laws are considered criminally responsible for their actions.
But does the same rule apply if you commit a crime in your sleep?
Recently, two Australians accused of serious criminal offences have successfully used parasomnias, a category of sleep disorders, in their defence.
Murder charges against a Melbourne woman were dropped last week after it was argued she was suffering from parasomnia when she fatally stabbed her husband.
It came just days after a Sydney man diagnosed with sexsomnia, a specific type of parasomnia, was found not guilty of having non-consensual sex with a woman.
Here’s what you need to know about parasomnias when they’re claimed as a legal defence.
What are parasomnias?
Parasomnias are a category of sleep disorders involving involuntary movements and behaviours, typically with no awareness or memory of the event.
“They vary between quite simple movements and quite complex movements,” Dr Linda Schachter, a sleep and respiratory physician and Sleep Health Foundation board member, told SBS News.
“The more complex behaviours can be very purposeful movements.”
Parasomnia events typically happen as you transition from one stage of sleep to another, but can also occur as you’re falling asleep or waking up, Schachter said.
The “less extreme” types of parasomnia include sleepwalking, sleep talking, night terrors, and sleep eating disorder, she said.
Sleep eating disorder is a kind of parasomnia. Source: Getty / freemixer
REM behaviour disorder, which involves people acting out their dreams during the rapid eye movement stage of sleep, can be a more serious type of parasomnia, Schachter said.
“A lot of our dreams are quite violent, but we don’t act them out because we are paralysed,” she said.
“But if you’ve lost that paralysis of REM sleep, you do act out your dream, and a lot of violent behaviours can occur.
“If you are dreaming that you are being attacked, your defence would be to fight back, and that’s really what these people are doing.”
Schachter said sexsomnia, which involves people acting out “sex and complex activities” during their sleep, is considered a very specific and rare type of parasomnia.
Do parasomnia events happen every night?
The frequency of parasomnia events varies between patients, Schachter said.
“Some people do do it every night. Other people, it’s just occasionally that they do it,” she said.
Factors such as being sleep deprived, having poor sleep hygiene, being unwell, being in a new environment, some antidepressants, and consuming alcohol or sedatives can make parasomnia events more frequent and severe, Schachter said.
“Other sleep disorders may also make these events worse,” she added.
Schachter said in most parasomnia cases, the person with the condition is more likely to harm themselves than someone else.
“But obviously in some conditions, particularly things like REM behaviour disorder or sexomnia where you’ve got a partner in bed … then obviously the partner may get hurt or injured during these events,” she said.
How are parasomnias diagnosed and treated?
Parasomnias are diagnosed through a full sleep study conducted in a hospital, Schachter said.
“We look at ‘do they have inappropriate movements in different stages of sleep and do they have other sleep disorders?'” she said.
Schachter said the main aim of managing parasmonias was to protect the safety of patients and those around them.
“So we may find out that you don’t need to treat it in that condition where it’s not harmful to somebody or to their partner … that’s obviously sleepwalking, night terrors, something like that,” she said.
If a patient’s parasomnia is causing harm to them or the people around them, Schachter said they would first address any other conditions or behaviours that were making it worse.
The main aim of managing parasmonias is to protect the safety of patients and those around them. Source: Getty / Visions
“If somebody had sleep apnoea, which is predisposing to some of these sleep disorders, you’d treat their sleep apnoea; you’d really put the importance on making sure you’re getting enough sleep; you’re not drinking alcohol, you’re not taking sleeping tablets,” she said.
“If it continues to be a problem, then you would treat them with medication.”
Schachter said she hoped that anyone with a history of a violent form of parasomnia, especially sexsomnia, would disclose it to a new partner before they slept in the same bed to limit the risks of them being harmed.
“They could then choose if they chose to sleep with you in the same bed, or maybe until it was felt that it was safer that they slept in separate beds or something like that till it was actually safe to sleep next to the person,” she said.
“Maybe even the partner and the person who’s got the disorder could see a sleep doctor together and discuss how to minimise the events that are occurring.”
How can parasomnias be claimed as a criminal defence?
Conditions that cause bodily movements that are not consciously controlled and that a person has no memory or knowledge of come under the legal defence of automatism, Christopher Rudge, a law lecturer at the University of Sydney and expert in health law and medical regulation, said.
That defence is based on an ancient rule in law that “an involuntary act does not result in criminal responsibility being attributed to the actor”, he said.
There are two types of automatism: insane and sane.
Insane automatism is the result of a mental illness or ‘disease of the mind’, such as someone having a psychotic hallucination and attacking a person in the same room as them because they believe they’re their enemy who is trying to hurt them, Rudge said.
“Sexsomnia, the way it’s developed between the science and the courtrooms, has been slotted into sane automatism, meaning it’s [considered] a transient and non-recurrent malfunction of the mind,” he told SBS News.
Sexsomnia can be used as a legal defence in sexual assault cases. Source: Getty / Chris Ryan
Other types of parasomnia are also considered sane automatism.
In such cases, the defendant only needs to prove there was “a reasonable possibility” that their actions were involuntary, Rudge said.
“That will be enough to create the reasonable doubt that the prosecution has to get rid of [to win the case],” he said.
“When you have the medical evidence in court and there is an expert answering questions under cross-examination saying, ‘No, this is very possible. I’ve done an analysis of the defendant, everything they are saying is consistent with this diagnosis’, then the prosecution is very disadvantaged.”
Why is it controversial?
Rudge noted the science around sexsomnia is still “in its infancy” and there’s debate among experts about whether its classification as a temporary malfunction that occurs in an otherwise healthy mind is accurate or whether it should be considered a mental health impairment caused by an underlying mental illness.
He said the “lack of coordination and development in the psychiatric diagnosis” of sexsomnia was concerning because it “spills into the way the law can deal with it”.
“It’s a parasomnia, which means you are half asleep, and it’s a non-REM parasomnia, which means you’re not in the rapid eye movement, deep sleep,” Rudge said.
“So if it is a delusion, then that’s more like a psychopathology. But if they are half asleep, what is the threshold of volition [making a conscious choice] there? And if the actions of the person are very complex, what is the nature of the mind in that situation?”
While Rudge didn’t suggest this had happened in Australia, he said the possible exploitation of parasomnia as a legal defence in violent criminal cases also concerned him.
“We need to have scrutiny in terms of those factual matters if this is going to be controlled,” he said.
“If the defendant apologised the morning after the incident, that may indicate a memory; or if they inadvertently described something that happened during that period in which they were supposed to have been in a non-voluntary or non-volitional state; or if they did something during the incident that demonstrated consciousness or volition, like engaging in complex discussion, these things could potentially be used to rule out the defence.”
But the “asymmetrical evidentiary burdens” in cases with a defence of parasomnia that if the prosecution doesn’t believe they have “a reasonable prospect of success”, it won’t even make it to court, Rudge said.
“In some circumstances, you could challenge the defence in two ways,” he said.
“It could be challenged where there are two different scientific diagnoses in evidence — where one expert says it is sexsomnia and another said it is not. Or where a second expert says the acts resulted from an underlying pathological disorder.
“Or you could challenge it on the facts if certain facts have been revealed. The prosecutor could say: ‘Well, the facts suggest this diagnosis is not correct, because the defendant remembered the events and described them unprompted’. But I don’t think we’ve seen many cases involving those kinds of challenges yet.”
If you or someone you know is impacted by sexual assault, call 1800RESPECT on 1800 737 732, text 0458 737 732, or visit . In an emergency, call 000.
