Mental health
Dr Jacob Rajesh, a senior consultant psychiatrist at Promises Healthcare, said while weapon attacks may occur during gang fights, or when people are under the influence of alcohol or drugs, there are also instances of assailants with underlying mental illness.
This was the case with Surajsrikan Diwakar Mani Tripathi, who fatally stabbed a stranger who jogged past him at Punggol Field in 2020.
The assailant, then 20, had severe social anxiety disorder, obsessive compulsive disorder and dyscalculia, which is a learning disability in mathematics, said Dr Rajesh, who conducted the psychiatric assessment for the case.
Forensic psychiatrists check if accused persons have a history of mental illness, and evaluate their functioning and mental state at the time of offence.
If there is a link between the mental condition and the offence, then it has some mitigating value, said Dr Rajesh.