Did the television, books, internet or a pet ever do this?
Yes
https://academic.oup.com/schizophreniabulletin/article/50/3/...
> Our findings provide support for the hypothesis that cat exposure is associated with an increased risk of broadly defined schizophrenia-related disorders
https://www.sciencedirect.com/science/article/abs/pii/S00223...
> Our findings suggest childhood cat ownership has conditional associations with psychotic experiences in adulthood.
https://journals.plos.org/plosone/article?id=10.1371/journal...
> Exposure to household pets during infancy and childhood may be associated with altered rates of development of psychiatric disorders in later life.
But there have always been crank forums online. Before that, there were cranks discovering and creating subcultures, selling/sending books and pamphlets to each other.