Thank you - yes, to me it's a very broad term. Even schizophrenia varies a bit by culture and by degree of disordered thinking.
I had to defend a post I made that stated I know schizophrenics who are high functioning (and I do) ,
Thought disorder, or formal thought disorder, is one of Schneider’s First Rank Symptoms, most of which being necessarily present (at the time, mid-twentieth century or thereabouts), he postulated, for the making of a definitive diagnosis of schizophrenia.
I’ve been told that one would need to understand exactly what Schneider meant, in the German, in order fully to grasp each of the First Rank Symptoms as demonstrated in schizophrenia.
Despite European and American psychiatry evolving somewhat differently thereafter, the phenomenon of thought disorder is still currently useful in understanding schizophrenia on both sides of the pond.
The Indian quantitative research study published in 2020 that I’ve linked above differentiates between thought disorder as currently understood and classical thought disorder (more of a Schneiderian emphasis).
The researchers urge that clinicians do not forget that the profound classical thought disorder, commonly seen in schizophrenia, leads on to executive dysfunction, so there is extreme difficulty in planning, then carrying out, actions.
I agree with you that a person with schizophrenia would have been very unlikely to have planned and executed such a crime.
I agree that the influence of certain drugs could have enabled a person to carry out this crime. I think that some drugs cause a person’s mentation to be disturbed, which is another way of saying that they can cause thinking to be disturbed or disordered. If they also exacerbate feelings of rage, then we have a recipe for disaster, when a weapon is to hand. IMO.
What a dreadful tragedy.