“Self-immolation is an act of killing oneself as a sacrifice. While usage since the 1960s has typically referred only to setting oneself on fire, the term historically refers to a much wider range of suicidal choices.”
“Cases in which people use fire when attempting or committing suicide are not common but nevertheless constitute a cause of admission to burns units worldwide. Usually these people are suffering from stress and have been diagnosed as mentally ill. Schizophrenia, depression, and personality disorders are the most frequently diagnosed conditions.”
https://www.ncbi.nlm.nih.gov/pmc/journals/1231/