A bare assertion by a psychiatrist that a court 'might take into account' an offender's depressed mood 'by way of mitigation', without elaboration of the causal mechanism linking the mental illness to the offending, is inadequate to establish a causal connection between mental illness and the commission of an offence for sentencing purposes. The onus is on the offender to prove such a connection on the balance of probabilities, ordinarily through expert evidence.
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