Objective: Cannabis consumption produces psychopathology, in some cases psychotic episodes, which are of our interest in this work. However, the relationship between cannabis use and psychosis has not been fully elucidated. The objectives of this work are to (1) review the current state of knowledge on the association of cannabis use with the risk of the development of psychosis or psychotic symptoms in people without schizophrenia and (2) assess the consistency of the hypothesis that cannabis use is associated with increased risk of psychosis in people without schizophrenia. Method: This work included research done in humans until May 2018 with the keywords ‘cannabis’ and ‘psychosis’, published in English and Spanish, in the PubMed database. Results: In all, 66 papers were analyzed, of which 23 were cohort trials and 43 were reviews. Conclusion: Cannabis use doubles the risk of developing psychosis in vulnerable people. There even exists a relationship regarding the dose used and the age of first use. Gene–environment interactions that modulate the association between cannabis use and the presence of psychosis have also been described.

Background. Cannabis is the most widely used illegal drug in the world. Both an early cannabis use onset and the amount used contribute to the risk of suffering mental disorders in adulthood. Objective. Review longitudinal studies conducted on adolescents associating early cannabis use with the subsequent occurrence of mental disorders. Method. A search was conducted in PubMed until December 2016, focusing on longitudinal researches and prioritizing studies that clearly distinguished between an early and late onset of cannabis use. To achieve the objective, the word "cannabis" was used in combination with the main psychiatric diseases. A manual search of articles that appeared in the references was also conducted. Results. Fifteen studies met the inclusion criteria, but only five studies discriminated clearly between early and late onset of cannabis use. An association was found between early onset of cannabis use and mental disorders, particularly psychosis. The information regarding affective and anxiety disorders is more controversial. Discussion and conclusion. Early onset of cannabis use is associated with mental disorders, especially psychosis. Prevention plans for cannabis use in adolescents should be developed in order to decrease the risk of mental disorders.

IntroductionSubstance use disorder is a growing phenomenon among old adults. It is usually significantly undervalued, misidentified, under diagnosed and poorly treated. It has been related to cognitive impairment but there are few studies focused on the elderly.AimTo evaluate the relationship between drug use and cognitive impairment in old adults.MethodsWe conducted a prospective study (basal and 6 month follow up) in 67 patients over 65 years old seeking for treatment for drug misuse (alcohol and prescription drugs, mainly benzodiacepines) in addiction and dual diagnosis unit in Barcelona. A specific protocol was performed to evaluate attention, executive function, working memory, learning capacity, fonetic and visual fluency, decision-making, visual construction and cognitive flexibility (FCT, CPT-II, N-BACK, COWAT FAS, TAP, SDMT, IGT, CVLT, TOL, RFFT, STROOP). Patients were compared with a control group (healthy non drug users) with same characteristics (gender, age range and education status). The protocol consisted in two separated sessions of 90 minutes each one performed by a neuropsychologist.ResultsResults obtained suggested that patients under drug misuse had worse scores in fluency, visual construction, memory and attention compared with controls. After 6 month treatment and achieving abstinence patients improve in cognitive skills as verbal learning, short-term memory and free recall of verbal information. Cognitive impairment profile changes depending on the substance abused (alcohol or benzodiacepines).ConclusionsDrug use can produce deleterious effects in old adults. However, those who achieve abstinence may improve some cognitive functioning as verbal learning, short-term memory and free recall of verbal information.Disclosure of interestThe authors have not supplied their declaration of competing interest.