Almost no mass shootings were carried out by someone with a serious mental illness. Almost all of them made a conscious decision to do what they did and made a plan to do it. They learned to do what they did from internet forums, news reports of other shootings, abhorrent “influencers,” and the like, and they didn’t do what they did impulsively or based on a psychotic though process. Psych hospitals and deinstitutionalization have nothing at all to do with mass shootings