Patients with First Episode Psychosis Take More and Stronger Cannabis than Controls
M. Di Forti
European Psychiatry 2009 DOI: 10.1016/s0924-9338(09)70377-3 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Case-control study Peer reviewed |
|---|---|
| Sample size | 311 |
| Population | 191 first-episode psychosis patients and 120 matched healthy volunteers in South East London |
| Topics | Cannabis |
| Key findings | First-episode psychosis patients were more likely than controls to use higher-potency cannabis (Skunk/Sinsemilla: 86.8% vs 27.7%), to use it more frequently, and to have used it for longer; the adjusted odds ratio for preferential Skunk use was 7.4 (95% CI 3.4-17.2). |
Abstract
Epidemiological studies have reported that the increased risk of developing psychosis in cannabis users is dose related. In addition, experimental research has shown that the active constituent of cannabis responsible for its psychotogenic effect is Delta-9-Tetrahydrocannabinol (THC) (Murray et al, 2007). Recent evidence has suggested an increased in potency (% TCH) in the cannabis seized in the UK (Potter et al, 2007). We predicted that first episode psychosis patients are more likely to use higher potency cannabis and more frequently than controls. We collected information concerning socio-demographic, clinical characteristics and cannabis use (age at first use, frequency, length of use, type of cannabis used) from a sample of 191 first-episode psychosis patients and 120 matched healthy volunteers. Cases were more likely to be regular users (p=0.05), to be current users (p=0.04) and to have smoked cannabis for longer (p=0.01). Among cannabis users, 86.8% of 1st Episode Psychosis Patients preferentially used Skunk/Sinsemilla compared to 27.7% of Controls. Only 13.2 % of 1st Episode psychosis Patients chose to use Resin/Hash compared to 76.3% of controls (OR*= 7.4 95% CI 3.4- 17.2, Adjusted for age, gender, ethnicity, level of Education and employment status).The concentration of TCH in these in South East London, ranges between 8.5 and 14 % (Potter et al, 2007). Controls (47%) were more likely to use Hash (Resin) whose average TCH concentration is 3.4% (Potter et al, 2007). Patients with first episode psychosis have smoked higher potency cannabis, for longer and with greater frequency, than healthy controls.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |