Is it possible to develop immunity to mental health drugs? After watching The Princess Bride, I discovered this word: Mithridatism, "the practice of protecting oneself against a poison by gradually self-administering non-lethal amounts."

Is it possible for people to become immune to mental health drugs after sometime of taking them?
It seems that it is possible.

Norman Sussman, MD (2017) discusses pharmacological and non-pharmacological causes of treatment resistance.


  Treatment resistance is addressed in the latest edition of the [Kaplan and Sadock's] Comprehensive Textbook of Psychiatry as follows: “Some patients fail to respond to repeated trials of medication. No single factor can explain the ineffectiveness of the various interventions in these cases. Strategies in these cases include the use of drug combinations, high-dose therapy, and use of unconventional drugs. Limited evidence is available on the comparative success rates associated with any given strategy (Sadock et al., 2017).” This Special Report on treatment resistance provides expert guidance on how to treat patients who are still unresponsive after multiple unsuccessful attempts at intervention for some common mental disorders. ADHD, PTSD, panic disorder, and bipolar disorder are especially difficult to treat successfully, for a number of reasons...


References

Sadock, B. J., Sadock, V. A., &amp; Ruiz, P. (2017). Kaplan and Sadock's Comprehensive Textbook of Psychiatry 10th ed. Philadelphia: Wolters Kluwer Health/Lippincott Williams &amp; Wilkins.

Sussman, N. (2017). Treatment Resistance in Psychiatry. Psychiatric Times 34(11) Special Report Retrieved&nbsp;from:&nbsp;http://www.psychiatrictimes.com/special-reports/introduction-treatment-resistance-psychiatry