Abstract
We have described a clinical case of psychotic disorder induced by synthetic cathinones in one drug-addicted monozygotic twin. This clinical case is unique, because it offers the opportunity to observe many features of the singularity of the dependence syndrome in twin brothers: drug choice; motivation to use drugs; and the development of multiple, long-lasting psychoses in one of the brothers. We pursued a twelve-month follow-up of this case. The case substantiates the paucity of a fundamental understanding of mental disorders and highlights the importance of further research into the clinical features of drug-induced psychoses, especially those induced by novel psychoactive substances such as synthetic cathinones.