This type of crime is almost always connected to SSRIs. The more you send people to shrinks, the more violence you will see. It pays.
Selective serotonin reuptake inhibitors (SSRIs)
The reason is because those on the meds are usually violent and sick in the mind in the first place, with or without the meds. It could be that without the meds, violent acts would be much more common. Hard to prove a negative though. The only,way really,is to compare how many violent acts sick people commit off meds, compared to on meds, and see if there is a reduction.