International Classification of Diseases (general information)
V. Mental and Behavioral Disorders (significantly, not called "diseases." This is significant because other sections of ICD-10 do describe what it calls "diseases" and therefore the ICD-10 must believe there is a difference, because otherwise it would use the same word).
So, even within mainstream psychiatry as practiced today, there is no mental "disease."
According to a survey that took place over 2010-2011, ICD-10 is used by the majority of clinical psychiatrists worldwide.