There were several factors that went into this catastrophic bad trip I believe.

First and most importantly was his existing mental illnesses. Certain things he told me that I thought were poetic license or spiritual things, which in hindsight I now realise were delusional symptoms before he even took psychedelics. He also had PTSD and paranoia from his time in the military and experience being abused as a child.

Secondly I believe he took mushrooms in a risky manner. The first times he took psychedelics it was beautiful. The times we took LSD together were among the most beautiful and profound experiences I've ever had.

However he started self medicating with them much more frequently than anyone would advise. I'm talking weekly. And for a time it was euphoric and made him feel like he was tapping into his divine nature.

A week before the catastrophic "bad trip" he had his first bad trip. He felt rapid oscillations between euphoria and suicidal despair, and a person who was with him at the time described him "talking to the wall to people who weren't there".

After that experience he said he never wanted to take mushrooms again. I supported that as I was scared by his experience and I had also had a separate bad trip caused by taking mushrooms while "bored" (not taking them seriously) which made me wary of them in general.

A week later the loved one who would eventually become his victim, suggested they take mushrooms together. We were all on video chat together. I was in Australia he and the other person were in the US. I told him not to take them citing his previous bad trip. The other person said "don't worry it's a low dose". But it didn't look like a low dose to me. I don't know why he decided to go ahead with it. It was extremely foolhardy and the choice he is most responsible for. Not the shooting itself because he didn't intend for that to happen and his mindset was completely detached from reality when he did it. But he was sober when he thought "I had a suicidal bad trip last week, why not take mushrooms again today" and that was very dumb and while he couldn't have expected that he would do something so incredibly out of character as to harm another person, he could have reasonably expected that he would have harmed himself given the suicidal nature of his previous bad trip.

The third possible factor is that there may have been tainting of the mushrooms because it's possible they contained PCP. I don't know if this was true but it could have been. However I have read of a case called Thomas Chan where it was just plain mushrooms and it caused a psychotic break almost identical to what happened to my partner. So I take this factor with a grain of salt especially since his loved one took the same mushrooms and didn't have a bad trip.

The fourth factor is that it was a bad set and setting for the trip. He had just watched a movie about hitmen and spies, which ended up factoring into the "conspiracy" nature of the delusion that later occured during his psychotic break. He also had a gun in the house because he was a security guard. Not a safe place to take mind altering drugs.

Anyway it was extremely horrific and tragic what happened. An innocent life destroyed and a good hearted person locked up for decades because of a risky decision and an unpredictable drug that interacted terribly with his preexisting mental illness.