Cannabis Use and Dependence among French Schizophrenic Inpatients

Causal Beliefs About and Perceptions of Illness in Persons Experiencing Schizophrenia and in Close Relatives of Such Individuals: An Exploratory Study

BACKGROUND

The cause to which persons experiencing schizophrenia attribute their illness influences emotional and adjustment variables. This is also true for close relatives (CRs), who are important players in the affected individual's environment and whose mood can influence the person's day-to-day life or treatment adherence. Recent literature has highlighted a need to further explore the impact of causal beliefs on different aspects of recovery as well as on stigma.

AIMS

The objective of this study was to explore causal beliefs about the illness and their relationship to other illness perceptions and stigma among persons experiencing schizophrenia and their CRs.

METHODS

Twenty French individuals experiencing schizophrenia and 27 CRs of individuals with schizophrenia answered the Brief Illness Perception Questionnaire, which investigates probable causes of an illness and other illness perceptions, and the Stigma Scale. A semi-structured interview was used to collect information about diagnosis, treatment, and access to psychoeducation.

RESULTS

The individuals with schizophrenia identified fewer causal attributions than the CRs. They were more likely to endorse psychosocial stress and family environment as probable causes, while CRs mostly favored genetic explanations. We found significant relationships between causal attributions and most negative perceptions of the illness, including components of stigma, in both samples. Among CRs, having received family psychoeducation was strongly correlated with viewing substance abuse as a probable cause.

CONCLUSIONS

Relationships between causal beliefs about illness and perceptions of illness both in individuals experiencing schizophrenia and in CRs of such individuals should be explored further with harmonized and detailed tools. Assessing causal beliefs about schizophrenia as a framework for psychiatric clinical practice could prove useful for all those involved in the recovery process.

Activation of tyrosine phosphatase PTP1B in pyramidal neurons impairs endocannabinoid signaling by tyrosine receptor kinase trkB and causes schizophrenia-like behaviors in mice

Schizophrenia is a debilitating disorder affecting young adults displaying symptoms of cognitive impairment, anxiety, and early social isolation prior to episodes of auditory hallucinations. Cannabis use has been tied to schizophrenia-like symptoms, indicating that dysregulated endogenous cannabinoid signaling may be causally linked to schizophrenia. Previously, we reported that glutamatergic neuron-selective ablation of Lmo4, an endogenous inhibitor of the tyrosine phosphatase PTP1B, impairs endocannabinoid (eCB) production from the metabotropic glutamate receptor mGluR5. These Lmo4-deficient mice display anxiety-like behaviors that are alleviated by local shRNA knockdown or pharmacological inhibition of PTP1B that restores mGluR5-dependent eCB production in the amygdala. Here, we report that these Lmo4-deficient mice also display schizophrenia-like behaviors: impaired working memory assessed in the Y maze and defective sensory gating by prepulse inhibition of the acoustic startle response. Modulation of inhibitory inputs onto layer 2/3 pyramidal neurons of the prefrontal cortex relies on eCB signaling from the brain-derived neurotrophic factor receptor trkB, rather than mGluR5, and this mechanism was defective in Lmo4-deficient mice. Genetic ablation of PTP1B in the glutamatergic neurons lacking Lmo4 restored tyrosine phosphorylation of trkB, trkB-mediated eCB signaling, and ameliorated schizophrenia-like behaviors. Pharmacological inhibition of PTP1B with trodusquemine also restored trkB phosphorylation and improved schizophrenia-like behaviors by restoring eCB signaling, since the CB1 receptor antagonist 1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-1-piperidinyl-1H-pyrazole-3-carboxamide blocked this effect. Thus, activation of PTP1B in pyramidal neurons contributes to schizophrenia-like behaviors in Lmo4-deficient mice and genetic or pharmacological intervention targeting PTP1B ameliorates schizophrenia-related deficits.

Psychotic disorders hospitalizations associated with cannabis abuse or dependence: A nationwide big data analysis

OBJECTIVES

We aimed to describe and correlate the hospital panorama of psychotic disorders (PD) with cannabis use (CU) trends in all Portuguese public hospitals.

METHODS

We conducted a retrospective observational study that analysed all hospitalizations that occurred in Portuguese public hospitals from 2000 to 2015. Hospitalizations with a primary diagnosis of PD or schizophrenia were selected based on Clinical Classification Software diagnostic single-level 659. Episodes associated with CU were identified by the International Classification of Diseases Version 9, Clinical Modification code 304.3/305.2 that correspond to cannabis dependence/cannabis abuse.

RESULTS

The number of hospitalizations with a primary diagnosis of PD and schizophrenia associated with CU rose 29.4 times during the study period, from 20 to 588 hospitalizations yearly (2000 and 2015, respectively) with a total of 3,233 hospitalizations and an average episode cost of €3,500. Male patients represented 89.8% of all episodes, and the mean/median age at discharge were 30.66/29.00 years, respectively. From all hospitalizations with a primary diagnosis of PD or schizophrenia, the ones with a secondary diagnosis of CU rose from 0.87% in 2000 to 10.60% in 2015.

CONCLUSIONS

The increase on secondary diagnosis coding and the change on cannabis patterns of consumption in Portuguese population with an increasing frequency of moderate/high dosage cannabis consumers may explain the rise on PD hospitalizations.

Compulsive buying in Paris psychology students: Assessment of DSM-5 personality trait domains

Compulsive buying is associated with significant psychiatric comorbidity, such as personality disorders. Few studies have focused on the dimensional model of personality disorders in compulsive buying. We aimed to assess the eventual presence of personality dysfunctions in compulsive buying according to the Diagnostic and Statistical Manual of Mental Disorder, 5th edition (DSM-5) dimensional conception of personality disorders. We screened online compulsive buying (QABB), characterized purchasing behavior and explored DSM-5 personality trait domains (Personality Inventory for DSM-5-Brief Form [PID-5-BF]) in 233 Paris psychology students using an online self-reporting questionnaire. The prevalence of compulsive buying among students was 7.7% (n = 18). The favorite items purchased by compulsive buyers were clothing and cosmetic products. Three mean trait domain scores were significantly higher for CB+ than CB- students: negative affect, detachment and disinhibition. Our findings suggest that compulsive buyers distinctively feature pathological DSM-5 dimensional personality trait domains.

Cannabis and Psychosis: a Critical Overview of the Relationship

Interest in the relationship between cannabis use and psychosis has increased dramatically in recent years, in part because of concerns related to the growing availability of cannabis and potential risks to health and human functioning. There now exists a plethora of scientific articles addressing this issue, but few provide a clear verdict about the causal nature of the cannabis-psychosis association. Here, we review recent research reports on cannabis and psychosis, giving particular attention to how each report provides evidence relating to two hypotheses: (1) cannabis as a contributing cause and (2) shared vulnerability. Two primary kinds of data are brought to bear on this issue: studies done with schizophrenic patients and studies of first-episode psychosis. Evidence reviewed here suggests that cannabis does not in itself cause a psychosis disorder. Rather, the evidence leads us to conclude that both early use and heavy use of cannabis are more likely in individuals with a vulnerability to psychosis. The role of early and heavy cannabis use as a prodromal sign merits further examination, along with a variety of other problem behaviors (e.g., early or heavy use of cigarettes or alcohol and poor school performance). Future research studies that focus exclusively on the cannabis-psychosis association will therefore be of little value in our quest to better understand psychosis and how and why it occurs.

mHealth App for Cannabis Users: Satisfaction and Perceived Usefulness

OBJECTIVE

The aim of this study was to describe the characteristics of cannabis users and their levels of satisfaction with Stop-cannabis, an app intended for cannabis users who want to stop or reduce their cannabis use or prevent relapse.

METHODS

A cross-sectional online survey was administered to users of Stop-cannabis, a French-language app for iOS and Android devices. All app users were invited to participate in the survey via a message sent to the app.

RESULTS

For hundred and eighty-two users answered the survey. The app was used daily by 348 of the participants (around 70%). More than 80% of participants (397) considered the app to have helped them "a little" or "a lot" to stop or reduce cannabis consumption. Most of the users' suggestions were related to the number or the quality of the messages sent by, or displayed in, the app.

CONCLUSION

This pilot study supports the feasibility of such an app and its perceived usefulness. A self-selection bias, however, limits the conclusions of the study. The efficacy of the app should be evaluated in a randomized controlled trial.