Prognosis of schizophrenia in persons with and without a history of cannabis use

Abstract

BackgroundThe aim of the study was to determinate whether schizophrenia patients with a history of cannabis use have a different prognosis, with regards to readmission and hospital duration, compared with those without a history of cannabis use.MethodThe present investigation was a cohort study of 50 087 Swedish men with data on cannabis use at the ages of 18–20 years. A total of 357 cases of schizophrenia were identified from in-patient care and followed up from 1973 to 2007.ResultsSchizophrenia patients with a history of cannabis use had a higher median duration of first hospital episode (59 days v. 30 days). Patients with a history of cannabis use had a higher median rate of readmission (10 times v. four times). Also, total number of hospital days was higher in patients with a history of cannabis use compared with those without (547 days v. 184 days). Patients with a history of cannabis use had an increased odds of having more than 20 hospital readmissions compared with non-users [3.1, 95% confidence interval (CI) 1.3–7.3] as well as an increased odds of hospital admission lasting more than 2 years (2.4, 95% CI 1.1–7.4) after controlling for diagnosis of personality disorders, family socio-economic position, IQ score, civil status, place of residence, risky use of alcohol and use of other drugs. Patients with a history of cannabis use were less likely to have paranoid schizophrenia compared with never users (8% v. 17%) in the first admission.ConclusionsSchizophrenia patients with a history of cannabis use had a significantly higher burden of lifetime in-patient care than non-cannabis users. Not only does cannabis increase the risk of schizophrenia, but also our findings indicate that the course and prognosis of schizophrenia may be more severe than schizophrenia cases in general.

Comorbid substance use disorders in schizophrenia: A latent class approach

“…In the remaining cases (35%), the onset of substance use disorders followed the onset of schizophrenia. These results suggest that the relationship between substance use disorders and schizophrenia could be bidirectional, a conclusion that has been supported by other studies (Foti et al, 2010; Leeson et al, 2012; Manrique-Garcia et al, 2014). In summary, our results indicate a negative, long-term, disease-modifying effect of substance use on the disease course of schizophrenia, despite potential short-term gain or symptom relief (Derosse et al, 2010).…”

The Role of Endocannabinoid Signaling in Cortical Inhibitory Neuron Dysfunction in Schizophrenia

“…Third, cannabis use is associated with an earlier age of onset of schizophrenia (13-15), particularly with higher levels of daily cannabis consumption and when the onset of cannabis use begins prior to age 15 (16, 17). Fourth, individuals with schizophrenia who use cannabis have longer durations of hospital stays and more frequent readmissions (18). However, these lines of evidence do not demonstrate that cannabis use is either necessary or sufficient to develop schizophrenia.…”

Le cannabis et ses effets délétères : pour un débat plus nuancé

“…Chez les individus souffrant de schizophrénie, la consommation de cannabis aurait également comme conséquence d'aggraver le cours de la maladie (Manrique-Garcia et al, 2014 ;van der Meer et Velthorst, 2015). À court terme, l'intoxication a effectivement été associée à une recrudescence transitoire des symptômes psychotiques au sein de cette population, tandis que le statut d'utilisation chronique prolongée a, quant à lui, été lié à un moins bon fonctionnement global, des hospitalisations psychiatriques allongées et plus fréquentes (Manrique-Garcia et al, 2014 ;van der Meer et Velthorst, 2015).…”

“…À court terme, l'intoxication a effectivement été associée à une recrudescence transitoire des symptômes psychotiques au sein de cette population, tandis que le statut d'utilisation chronique prolongée a, quant à lui, été lié à un moins bon fonctionnement global, des hospitalisations psychiatriques allongées et plus fréquentes (Manrique-Garcia et al, 2014 ;van der Meer et Velthorst, 2015). La consommation de cannabis serait donc associée à une aggravation de la maladie psychotique chez les personnes qui en souffrent.…”