BACKGROUND: Cannabis is frequently used among individuals with @entity716 and is associated with poor clinical outcomes. However, little is known about the effect of @entity835 use on the response to antipsychotic medications and how use could affect outcomes. Using natural language processing on clinical data from a large electronic case register, we sought to investigate whether resistance to antipsychotic treatment mediated poor clinical outcomes associated with @entity835 use. METHODS: Data were obtained from 2026 @entity1 with @entity716 in south London, UK. Cannabis use documented in free text clinical records was identified with natural language processing. Data for age, sex, ethnicity, marital status, @entity914 diagnosis, subsequent hospital admission, and number of unique antipsychotic medications prescribed were obtained using the Clinical Record Interactive Search instrument. The association of these variables with @entity835 use was analysed with multivariable regression and mediation analysis. FINDINGS: 939 @entity1 (46  3%) with @entity716 were using @entity835 at first presentation. Cannabis use was most strongly associated with being 16-25 years old, male, and single, and was also associated with an increase in number of hospital admissions (incidence rate ratio 1  50, 95% CI 1  25-1  80), compulsory hospital admission (odds ratio 1  55, 1  16-2  08), and number of days spent in hospital (b coefficient 35  1 days, 12  1-58  1) over 5 years' follow-up. An increase in number of unique antipsychotic medications mediated an increase in number of hospital admissions (natural indirect effect 1  11, 1  04-1  17; total effect 1  41, 1  22-1  64), compulsory hospital admission (1  27, 1  10-1  45; 1  71, 1  05-2  78), and number of days spent in hospital (16  1, 6  7-25  5; 19  9, 2  5-37  3). INTERPRETATION: We showed that a substantial number of @entity1 with @entity716 used @entity835 and that its use was associated with increased likelihood of hospital admission and number of days spent in hospital. These associations were partly mediated by an increase in number of unique antipsychotic medications prescribed. These findings suggest that @entity835 might reduce response to conventional antipsychotic treatment and highlight the importance of strategies to reduce its use. FUNDING: National Institute for Health Research, UK Medical Research Council.

Cannabis use and treatment resistance in XXXX : a natural language processing study.

@entity835 :: ('MESH:D002189', 'Disease') :: ['cannabis'] @entity1 :: ('9606', 'Species') :: ['people'] @entity716 :: ('MESH:D011605', 'Disease') :: ['first episode psychosis'] @entity914 :: ('MESH:D011618', 'Disease') :: ['psychotic disorder']
@entity716 :: (MESH:D011605,Disease) :: ['first episode psychosis']
