Cage fighter rips out still-beating heart of trainer

[Ford Prefect]

Umm, no. At least not in Ohio. If you voluntarily take a drug and then commit an offense while under the influence, you can't claim diminished capacity from voluntary intoxication. We tend to view that as "taking the stuff to build up your nerve". Now if there was no reasonable expectation of the effects of intoxication (doubt it in this case), there may be a defense.

I come from a different legal background, where you can't actually get done for murder unless you commit an act with an intention to kill (more or less). It's a specifc intent crime, so if you didn't form that specific intent (or foresaw the likelihood of death as a consequence), you can't be charged for murder in Australia. This sort of intoxication could be used to throw doubt on the establishment of specific intent, unless he had planned to kill the victim prior to taking the drugs (in which it could be a case of 'Dutch Courage'), but given the actual events I find it kind of a stretch. The law is different between states and countries, so I don't know how well it will hold up in California, but in a specifically Tasmanian court I find it unlikely that you could establish an intention to commit murder, beyond all reasonable doubt, on the facts given in the news article.