The association between reasons for first using cannabis, later pattern of use, and risk of first-episode psychosis: the EU-GEI case-control study.

BACKGROUND: While cannabis use is a well-established risk factor for psychosis, little is known about any association between reasons for first using cannabis (RFUC) and later patterns of use and risk of psychosis. METHODS: We used data from 11 sites of the multicentre European Gene-Environment Interaction (EU-GEI) case-control study. 558 first-episode psychosis patients (FEPp) and 567 population controls who had used cannabis and reported their RFUC.We ran logistic regressions to examine whether RFUC were associated with first-episode psychosis (FEP) case-control status. Path analysis then examined the relationship between RFUC, subsequent patterns of cannabis use, and case-control status. RESULTS: Controls (86.1%) and FEPp (75.63%) were most likely to report 'because of friends' as their most common RFUC. However, 20.1% of FEPp compared to 5.8% of controls reported: 'to feel better' as their RFUC (χ2 = 50.97; p < 0.001). RFUC 'to feel better' was associated with being a FEPp (OR 1.74; 95% CI 1.03-2.95) while RFUC 'with friends' was associated with being a control (OR 0.56; 95% CI 0.37-0.83). The path model indicated an association between RFUC 'to feel better' with heavy cannabis use and with FEPp-control status. CONCLUSIONS: Both FEPp and controls usually started using cannabis with their friends, but more patients than controls had begun to use 'to feel better'. People who reported their reason for first using cannabis to 'feel better' were more likely to progress to heavy use and develop a psychotic disorder than those reporting 'because of friends'.

Interaction between cannabis consumption and childhood abuse in psychotic disorders: preliminary findings on the role of different patterns of cannabis use.

AIM: Several studies have suggested that lifetime cannabis consumption and childhood abuse synergistically contribute to the risk for psychotic disorders. This study aimed to extend existing findings regarding an additive interaction between childhood abuse and lifetime cannabis use by investigating the moderating role of type and frequency of cannabis use. METHODS: Up to 231 individuals presenting for the first time to mental health services with psychotic disorders and 214 unaffected population controls from South London, United Kingdom, were recruited as part of the Genetics and Psychosis study. Information about history of cannabis use was collected using the Cannabis Experiences Questionnaire. Childhood physical and sexual abuse was assessed using the Childhood Experience of Care and Abuse Questionnaire. RESULTS: Neither lifetime cannabis use nor reported exposure to childhood abuse was associated with psychotic disorder when the other environmental variable was taken into account. Although the combination of the two risk factors raised the odds for psychosis by nearly three times (adjusted OR = 2.94, 95% CI: 1.44-6.02, P = 0.003), no evidence of interaction was found (adjusted OR = 1.46, 95% CI: -0.54 to 3.46, P = 0.152). Furthermore, the association of high-potency cannabis and daily consumption with psychosis was at least partially independent of the effect of childhood abuse. CONCLUSIONS: The heavy use of high-potency cannabis increases the risk of psychosis but, in addition, smoking of traditional resin (hash) and less than daily cannabis use may increase the risk for psychosis when combined with exposure to severe childhood abuse.

Confirmation that the AKT1 (rs2494732) genotype influences the risk of psychosis in cannabis users.

BACKGROUND: Cannabis use is associated with an increased risk of psychosis. One study has suggested that genetic variation in the AKT1 gene might influence this effect. METHODS: In a case-control study of 489 first-episode psychosis patients and 278 control subjects, we investigated the interaction between variation at the AKT1 rs2494732 single nucleotide polymorphism and cannabis use in increasing the risk of psychosis. RESULTS: The rs2494732 locus was not associated with an increased risk of a psychotic disorder, with lifetime cannabis use, or with frequency of use. We did, however, find that the effect of lifetime cannabis use on risk of psychosis was significantly influenced by the rs2494732 locus (likelihood ratio statistic for the interaction = 8.54; p = .014). Carriers of the C/C genotype with a history of cannabis use showed a greater than twofold increased likelihood of a psychotic disorder (odds ratio = 2.18 [95% confidence interval: 1.12, 4.31]) when compared with users who were T/T carriers. Moreover, the interaction between the rs2494732 genotype and frequency of use was also significant at the 5% level (likelihood ratio = 13.39; p = .010). Among daily users, C/C carriers demonstrated a sevenfold increase in the odds of psychosis compared with T/T carriers (odds ratio = 7.23 [95% confidence interval: 1.37, 38.12]). CONCLUSIONS: Our findings provide strong support for the initial report that genetic variation at rs2494732 of AKT1 influences the risk of developing a psychotic disorder in cannabis users.

Depression, anxiety and anger in subtypes of irritable bowel syndrome patients.

The present study aimed to elucidate the differences in depression, anxiety, anger, and quality of life in a sample of non-psychiatric IBS patients, starting from the hypothesis that IBS subtypes may have different symptomatic expressions of negative emotions with different outcomes on quality of life measures. Forty-two constipation-predominant IBS (C-IBS) subjects and 44 diarrhea-predominant IBS (D-IBS) subjects, after an examination by a gastroenterologist and a total colonoscopy, underwent a clinical interview and psychometric examination for the assessment of depression, anxiety, anger and quality of life. IBS subtypes showed different symptomatic profiles in depression, anxiety and anger, with C-IBS patients more psychologically distressed than D-IBS subjects. Affective and emotional symptoms should be considered as specific and integral to the syndrome, and recognizing the differences between IBS subtypes may have relevant implications for treatment options and clinical outcome.

High-potency cannabis and the risk of psychosis.

BACKGROUND: People who use cannabis have an increased risk of psychosis, an effect attributed to the active ingredient Delta 9-tetrahydrocannabinol (Delta 9-THC). There has recently been concern over an increase in the concentration of Delta 9-THC in the cannabis available in many countries. AIMS: To investigate whether people with a first episode of psychosis were particularly likely to use high-potency cannabis. METHOD: We collected information on cannabis use from 280 cases presenting with a first episode of psychosis to the South London & Maudsley National Health Service (NHS) Foundation Trust, and from 174 healthy controls recruited from the local population. RESULTS: There was no significant difference between cases and controls in whether they had ever taken cannabis, or age at first use. However, those in the cases group were more likely to be current daily users (OR = 6.4) and to have smoked cannabis for more than 5 years (OR = 2.1). Among those who used cannabis, 78% of the cases group used high-potency cannabis (sinsemilla, 'skunk') compared with 37% of the control group (OR 6.8). CONCLUSIONS: The finding that people with a first episode of psychosis had smoked higher-potency cannabis, for longer and with greater frequency, than a healthy control group is consistent with the hypothesis that Delta 9-THC is the active ingredient increasing risk of psychosis. This has important public health implications, given the increased availability and use of high-potency cannabis.