Mentalism or sanism is a form of discrimination and oppression because of a mental trait or condition a person has, or is judged to have. This may or may not be described in terms of mental disorder or disability. The discrimination is based on numerous factors such as: stereotypes about neurodivergence (e.g. autism, ADHD, bipolar, schizophrenia, personality disorder diagnoses), specific behavioral phenomena (e.g. stuttering, tics), or supposed intelligence.
Like other "isms" such as sexism and racism, mentalism involves multiple intersecting oppressions and complex social inequalities and imbalances of power. It can result in covert discrimination by multiple, small insults and indignities. It is characterized by judgments of another person's perceived mental health status. These judgments are followed by actions such as blatant, overt discrimination (refusal of service, denying of human rights). Mentalism impacts how individuals are treated by the general public, by mental health professionals, and by institutions, including the legal system. The negative attitudes may also be internalized.
The terms mentalism (from mental) and sanism (from sane) have some widespread use, though concepts such as social stigma, and in some cases ableism, may be used in similar but not identical ways.