What is "psychiatric" in 'psychiatric disorder'?

When one claims that a disorder is psychiatric:What is the intrinsic nature of this adjective? What makes some kinds of experiences psychiatric, instead of  something else? And, in what way do these experiences affect the person who goes through them?References:de Haan, S.(2020). Enactive Psychiatry. Cambridge University Press.Dennett, D. C. (2013). Intuition pumps and other tools for thinking. Penguin Books.Freud, S. (1940). An outline of psycho-analysis. The International Journal of Psychoanalysis.Kandel, E.R. (2018). The disordered mind. What unusual brains tell us about ourselves. Robinson press. Schwarz, R.C. Sweezy, M. (2023). Internal Family System Therapy. The Guilford Family Therapy. -Every other Monday, at 12pm.Follow us on:Instagram: @mirror_podcast_Twitter/X: @mirror_podcastThis project exists in Italian as well: In Front of the Mirror - Il Podcast in Italiano