Sexsomnia as a Defence Against Sexual Assault Charges

Is the sleep disorder sexsomnia a mental health disorder, or isn't it?

Reviewed by Margaret Foley

Key points

• A diagnosis of sexsomnia translates differently across contexts.
• Legally, a sexsomniac is "not guilty of" or "not responsible for" sexual assault resulting from sexsomnia.
• Risk mitigation measures apply to verdicts only if sexsomnia is regarded as a mental health disorder.

Some words have different meanings in different contexts. For example, “I saw a bird,” is quite different from “I plan to saw some logs.” Divergent meanings of this type are typically quite acceptable.

But should a mental health diagnosis differ in meaning across contexts?

If the context is legal and a difference in meaning means someone is not criminally responsible for their actions, does it matter?

Let’s examine these questions in the case of sexsomnia.

A "sexsomniac" engages in sexual activity during sleep but can’t remember this because of impaired consciousness. His or her actions can lead to allegations of sexual assault or rape, yet sexual assault and rape that are nonvolitional are not indictable. This is because performing sex unwilfully gives rise to an "automatism' defence that has the effect of absolving a person of responsibility for actions performed without intention.

People diagnosed with sexsomnia satisfy the automatism defence.

The law must hold them either not guilty or not criminally responsible by reason of mental impairment if it cannot be proven they were awake at the time of performing sex relating to sexual assault charges. Which ruling applies depends on whether the law classifies sexsomnia as a mental health disorder.

Full acquittal or findings of not guilty apply only if sexsomnia is considered a "sane" automatism, one that is attributable to external factors that would be expected to deprive any "ordinary" person of volition temporarily. "External factors" do not include alcohol or transient mind-altering substances.

But sexsomnia relates to sleep, which arises from internal causes. The legal classification of a loss of volition arising from an internal cause is "insane" automatism. The applicable verdict when someone offends under the influence of an insane automatism is "not criminally responsible by reason of mental impairment." This is different from "not guilty."

A ruling that someone is not criminally responsible by reason of mental impairment invites consideration of potential ongoing risk to the public. Orders to protect the public follow where risk is probable.

Full acquittal of offences committed under an episode of sexsomnia makes little sense. Yet the judicial system treats sexsomnia as if it is not a mental health disorder discretionarily, which allows it to acquit people accused of sexual offences fully, without considering protective measures that might apply if sexsomnia was considered a mental health disorder.

In such cases, psychological or psychiatric opinion is sought insofar as it helps judges confirm a diagnosis of sexsomnia. The law then applies its own meaning to what is and isn’t a mental health disorder. But if, for instance, you have cancer, it is not for the courts to decide whether this is or isn’t a medical condition.

Further complicating the courts' discretionary ability, sexsomnia is listed in the Diagnostic and Statistical Manual of Mental Disorders, which means that full acquittal on the grounds of having a sane automatism conflicts with the psychiatric classification of sexsomnia.

This past September, a Sydney-based youth minister was found not guilty of 15 counts of inappropriate sexual conduct involving minors, including 11 counts of sexual intercourse.

Defence and prosecution agreed that evidence suggested he had sexsomnia—that the automatism defence applied to his case. Unfortunately, which type of automatism, sane vs. insane, wasn’t questioned. In this case, sexsomnia represented a sane automatism, and the minister was granted a full acquittal. But recall that a sane automatism is not a mental health disorder.

Measures to reduce potential reoffences were not considered because these apply only if an automatism satisfies the requirements of an insane automatism, a mental health disorder.

Importantly, court records show the minister shared beds with youth under his care, and co-sleeping is a known trigger of sexsomnia. Qualifying the judgment by enforcing conditions on bed-sharing with people who could become victims would have seemed appropriate.

Indeed, in giving evidence, the defence's consultant psychiatrist opined the minister “was still at risk of engaging in similar sexual behaviours.” He further set out treatment recommendations, “noting that the main intervention is mainly preventative by avoidance of being in close proximity to any future sexual partner.”

If the law regarded sexsomnia as a mental health disorder, ‘not criminally responsible by reason of mental impairment’ would have applied rather than straight out "not guilty," serving to minimise the chance of repeated untoward sexual acts.

Canada legislatively recognises sexsomnia as a mental health disorder, thereby precluding outright acquittal of sexsomnia-based offences. Other countries have not yet adopted this procedure.

Putting the law aside, diagnoses of sexsomnia are based chiefly on self-report and collateral history obtained mostly from family or significant others. The diagnostic criteria are primarily behavioural, including recurrent incomplete wakening, little or no dream imagery, and poor recall of events. Sleep studies are suggestive but not conclusive of the presence of the disorder. Substances and other medical or psychological conditions must not account for symptoms. And it's worth noting that there are no objective tests of malingering specific to sexsomnia.