Abstract
Psychotic patients with a lifetime history of cannabis use generally show better cognitive functioning than other psychotic patients. Some authors suggest that cannabis-using patients may have been less cognitively impaired and less socially withdrawn in their premorbid life. Using a dataset comprising 948 patients with first-episode psychosis (FEP) and 1313 population controls across 6 countries, we examined the extent to which IQ and both early academic (Academic Factor [AF]) and social adjustment (Social Factor [SF]) are related to the lifetime frequency of cannabis use in both patients and controls. We expected a higher IQ and a better premorbid social adjustment in psychotic patients who had ever used cannabis compared to patients without any history of use. We did not expect such differences in controls. In both patients and controls, IQ was 3 points higher among occasional-users than in never-users (mean difference [Mdiff] = 2.9, 95% CI = [1.2, 4.7]). Both cases and control daily-users had lower AF compared to occasional (Mdiff = -0.3, 95% CI = [-0.5; -0.2]) and never-users (Mdiff = -0.4, 95% CI = [-0.6; -0.2]). Finally, patient occasional (Mdiff = 0.3, 95% CI = [0.1; 0.5]) and daily-users (Mdiff = 0.4, 95% CI = [0.2; 0.6]) had better SF than their never-using counterparts. This difference was not present in controls (Fgroup∗frequency(2, 2205) = 4.995, P =. 007). Our findings suggest that the better premorbid social functioning of FEP with a history of cannabis use may have contributed to their likelihood to begin using cannabis, exposing them to its reported risk-increasing effects for Psychotic Disorders.
| Original language | English |
|---|---|
| Pages (from-to) | 517-529 |
| Number of pages | 13 |
| Journal | Schizophrenia bulletin |
| Volume | 46 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 10 Apr 2020 |
| Externally published | Yes |
Funding
The European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) Project is funded by grant agreement HEALTH-F2-2010–241909 (Project EU-GEI) from the Seventh Framework Programme. The project was further funded by the National Institute for Health Research, at South London and Maudsley NHS Foundation Trust and Kings College London. M.D.F. was supported by Medical Research Council (Clinician Scientist Fellowship - project reference MR/M008436/1) Wellcome Trust and the Royal Society (Sir Henry Dale Felloship, grant n. 101272/Z/13/Z) granted J.B.K.; The Brazilian study was funded by the Fundação de Amparo à Pesquisa do Estado de São Paulo (grant n. 2012/0417-0); E.V. was supported by the Seaver Foundation, NY; she is a Seaver Faculty Scholar; H.J. and P.B.J. were funded by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care East of England. The funders contributed to the salaries of the researchers involved, but they did not contribute in design and conduct of the study; collection, management, analysis and interpretation of the data; preparation, review or approval of the manuscript, and decision to submit the manuscript for publication.
| Funders | Funder number |
|---|---|
| European Network of National Schizophrenia Networks Studying Gene-Environment Interactions | HEALTH-F2-2010–241909 |
| National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care East of England | |
| Seaver Foundation | |
| South London and Maudsley NHS Foundation Trust and Kings College London | |
| Wellcome Trust | |
| Medical Research Council | MR/M008436/1 |
| National Institute for Health Research | |
| Royal Society | 101272/Z/13/Z |
| Fundação de Amparo à Pesquisa do Estado de São Paulo | 2012/0417-0 |
| Seventh Framework Programme |
Keywords
- cognition
- education
- marijuana
- preillness
- schizophrenia
- sociability