It’s fairly well-established that some people can react oddly to relatively harmless medications. The other day I read a first-hand account of someone who was prescribed a very common antidepressant, and upon taking it became homicidal. He wrote that he is ordinarily a very peaceful person and isn’t quick to anger, but after taking the antidepressant he felt an irresistable urge to kill his mother. He attacked her and she fled to the bathroom, where she locked herself in and shouted that she was calling the police. He said he then went downstairs and hid near the door with a kitchen knife, preoccupied with thoughts of ambushing and murdering the policemen when they entered. As it turns out, though, his mother had actually called some relatives for help, who didn’t show up until some time later. By then the homicidal mania had worn off to the point where he was more in control of himself, and he surrendered to his relatives who took him to the hospital, where it was verified that he had an adverse reaction to the antidepressant and was taken off it at once. No charges were filed; I believe he switched to another antidepressant and has since had no problems.
My question is this: if this person actually had killed his mother or a relative as a result of his drug-induced homicidal mania, would he necessarily have been brought to trial? It’s such a cut-and-dry case of an adverse psychotic reaction to a medication, and it’s unlikely his own family would have wanted to pursue charges against him, but would the state have been compelled to try him nonetheless?
If the case had gone to trial, and the defendant had pled not guilty by reason of temporary insanity (or at least presented his case as such, in jurisdictions where such a plea is not available), how would the prosecution have presented its case? Would it claim that he was negligent in taking the medication without precautions? (Seems unlikely—even I’ve taken prescription drugs where homicidal mania was listed as a possible but extremely unlikely side effect, but no pharmacist or doctor ever thought it prudent to advise me to take the first dose while wearing a straightjacket, just in case.) Are there any precedents for this sort of case?