The incidence of sluggish schizophrenia increased because, according to Snezhnevsky and his colleagues, patients with this diagnosis were capable of socially functioning almost normally. Their symptoms could resemble those of a neurosis or paranoia. Patients with paranoid symptoms retained insight into their condition, but overestimated their significance and had grandiose ideas of reforming society. Sluggish schizophrenia could have such symptoms as "reform delusions", "perseverance" and "struggle for the truth". As Viktor Styazhkin reported, Snezhnevsky diagnosed a reform delusion in every case where a patient "develops a new principle of human knowledge, drafts an ideal of human happiness or other projects for the benefit of mankind".