Mitchell argued that Schreiner's mental illness had been evolving for years. One of the key elements in the trial was journals kept by Schreiner. In the year before Brown's death, he began keeping a journal of his psychedelic experiences on psilocybin that included fantastical hallucinations and feelings of paranoia. Schreiner testified that he stopped using the drug in late 2018, but that his mental health continued to deteriorate. He began to believe that people were trying to kill him and that he was being set up to be charged as a pedophile. Mitchell went through testimony from an expert psychiatric witness who said that Schreiner displayed symptoms necessary for a diagnosis of "schizotypal personality disorder."