How do you formulate and diagnose patients with chronic psychosis that developed after methamphetamine use but persists after cessation of use?  

In some patients, psychotic symptoms persist long after methamphetamine cessation and lack the classic course or negative symptoms of schizophrenia. Diagnostically, how do you conceptualize and document these cases? Do you use a schizophrenia spectrum diagnosis, stimulant-induced psychotic disorder, or unspecified psychotic disorder?