People who consume cannabis on daily basis are likely to show episodes of psychosis and schizophrenia, according to a doctoral thesis.
Miguel Ruiz Veguilla, from the Institute of Neurosciences of the University of Granada in Spain, also claimed that the episodes of psychosis because of marijuana intake present certain specific characteristics, both before their appearance and in the clinical presentation of the psychosis.
During the study, Veguilla studied the risk factors associated with schizophrenia, identifying and characterizing in depth those psychosis associated with a continual consumption of cannabis.
The researcher carried out the study with 92 subjects, 50 of whom had developed a psychosis without presenting signs of an "abnormal neurodevelopment"-meaning that they had been doing well academically, they had a group of friends (no social isolation), and they presented a good motor coordination.
Also, the subjects did not show a family history of episodes of psychosis in first or second degree.
The researchers identified a connection between cannabis consumption and psychosis in subjects with a good premorbid performance.
They did not find any signs of minor neurological alterations, which, according to Veguilla, might point out "a psychopathological way associated with psychosis in subjects with less predisposition."
The researchers said that 66 percent of the patients with psychosis, who participated in the study and had a normal neurodevelopment, admitted to have consumed cannabis daily or almost every day.
On the other hand, 43 percent of the participants with markers of an abnormal neurodevelopment-those already indicated: bad previous social and academic behaviour, a family history and a "clumsier" attitude when they carry out tasks of motor coordination and complex motor acts-were drug users too.
The results of the thesis, titled 'Neurodevelopment and environmental stress in initial psychosis: transversal analysis of the ESPIGAS study', have been published in the journals Schizophrenia Research and European Psychiatry.