Freud in his letter to Jung sent a certificate of admission Otto Gross to the Burgholzli. Freud wrote: „I confirm that Dr. Otto Gross, private lecturer of neuropathology, whom I have known personally for years, urgently needs to be admitted to a closed institution so that he may achieve his withdrawal from opium and cocaine under medical supervision; throughout the last years he has been taking these medications in a manner that threatens his physical as well as psychological health.”
