Tanzi's own best-known works include a co-study with Riva on paranoia (1884), whilst he co-published the two-volume "Trattato delle malattie mentali" ("Treatise on Mental Maladies") with his former student Ernesto Lugaro in 1904, with the latter remaining a central text for Italian psychiatry until the late 1920s and a long-term influence on psychopathology and psychiatric clinics.