Plasma Endocannabinoid Alterations in Individuals with Substance Use Disorder are Dependent on the "Mirror Effect" of Schizophrenia

Involvement of the TRPV1 receptor and the endocannabinoid system in schizophrenia

BACKGROUND

Schizophrenia (SCZ) is a severe mental disorder, but its pathogenesis is still unknown, and its clinical treatment effect is very limited. Transient receptor potential vanilloid 1 (TRPV1) channel and the Endocannabinoid System (ECS)have been confirmed to be involved in the pathogenesis of SCZ, although their actions have not been fully clarified yet. The objective is to examine TRPV1 and ECS expression in the blood of schizophrenia patients and investigate their correlation with disease severity.

METHODS

This is a cross-sectional investigation. Peripheral blood samples were gathered from normal controls (NC, n=37), as well as individuals with schizophrenia, including first episode (n=30) and recurrent (n=30) cases. We employed western blot and ELISA techniques to quantify TRPV1, cannabinoid receptors 1(CB1), anandamide (AEA), and 2-arachidonoylglycerol (2-AG), and assess the severity of the patient's symptoms by means of the PANSS scale.

RESULTS

Compared to NC, TRPV1 levels showed a noticeable decrease in both first episode schizophrenia (f-SCZ group) and recurrent schizophrenia (r-SCZ group) subjects. Additionally, CB1 levels appeared increased in f-SCZ group. Furthermore, 2-AG levels were found to be elevated in both f-SCZ group and r-SCZ group compared to NC, whereas AEA levels were decreased in f-SCZ group but increased in r-SCZ group. Moreover, among schizophrenia patients, TRPV1 demonstrated a negative correlation with negative symptoms. Within r-SCZ subjects, CB1 displayed a negative correlation with relapse number, while 2-AG showed a correlation in the opposite direction.

CONCLUSIONS

This study provides initial clinical evidence of changed TRPV1 expression in schizophrenia, potentially linked to negative symptoms. These results suggest a possible dysfunction of TRPV1 and the endocannabinoid system (ECS), which might offer new avenues for medical interventions.

Absence of Evidence for Sustained Effects of Daily Cannabidiol Administration on Anandamide Plasma Concentration in Individuals with Cocaine Use Disorder: Exploratory Findings from a Randomized Controlled Trial

Background: Cannabidiol (CBD) has been proposed to have a therapeutic potential over a wide range of neuropsychiatric disorders, including substance use disorders. Pre-clinical evidence suggests that CBD can increase anandamide (AEA) plasma concentration, possibly mediating some of its therapeutic properties. Whether CBD exerts such an effect on AEA in individuals with cocaine use disorder (CUD) remains unknown. Aims: To explore the sustained effects of daily CBD administration on AEA plasma concentrations compared with placebo in CUD. Methods: We used data from a randomized, double-blind, placebo-controlled trial evaluating CBD's efficacy in CUD. Seventy-eight individuals were randomized to receive a daily oral dose of 800 mg CBD (n = 40) or a placebo (n = 38). Participants stayed in an inpatient detoxification setting for 10 days, after which they were followed in an outpatient setting for 12 weeks. AEA plasma concentration was measured at baseline and at 23-h post CBD ingestion on day 8 and week 4. A generalized estimating equation model was used to assess CBD's effects on AEA, and sensitivity analyses were computed using Bayesian linear regressions. Results: Sixty-four participants were included in the analysis. Similar mean AEA plasma concentrations in both treatment groups (p = 0.357) were observed. At day 8, mean AEA plasma concentrations (± standard deviation) were 0.26 (± 0.07) ng/mL in the CBD group and 0.29 (± 0.08) ng/mL in the placebo group (p = 0.832; Bayes factor [BF] = 0.190). At week 4, they were 0.27 (± 0.09) ng/mL in the CBD group and 0.30 (± 0.09) ng/mL in the placebo group (p = 0.181; BF = 0.194). Conclusion: While not excluding any potential acute and short-term effect, daily CBD administration did not exert a sustained impact on AEA plasma concentrations in individuals with CUD compared with placebo. Registration: clinicaltrials.gov (NCT02559167).

Endocannabinoid system alterations in schizophrenia: association with cannabis use and antipsychotic medication

Determining peripheral modulation of the endocannabinoid system (ECS) may be important for differentiating individuals with schizophrenia. Such differentiation can also be extended to subgroups of individuals, those who use cannabis and antipsychotic medications, particularly those who are treatment resistant. Patients and controls were recruited from the outpatient clinic of the Psychosis Group of the University of São Paulo, Brazil. A final sample of 93 individuals was divided into 3 groups: patients with schizophrenia using clozapine (treatment-resistant) (n = 29), patients with schizophrenia using another antipsychotic (n = 31), and controls (n = 33). By measuring the proteins and metabolites involved in the ECS pathways in the peripheral blood, AEA (anandamide), 2-AG (2-arachidonoyl ethanolamine), and CB2 receptor (peripheral) were quantified. Individuals reporting lifetime cannabis use had lower 2-AG plasma levels (p = 0.011). Regarding the CB2 receptor, the values of patients with schizophrenia and controls were similar, but those of patients using antipsychotics other than clozapine differed (p = 0.022). In generalized linear models to control for confounders, the use of cannabis remained the only factor that significantly influenced 2-AG levels. The relationship for non-clozapine antipsychotics as the only factor related to CB2 changes was marginally significant. We found for the first time that cannabis use and non-clozapine antipsychotic medication are potentially involved in the modulation of the ECS, specifically influencing 2-AG endocannabinoid and CB2 receptor levels. More studies regarding the ECS are needed since it has been increasingly related to the physiopathology of schizophrenia.

Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis

OBJECTIVES

The liberalisation of cannabis laws, the increasing availability and potency of cannabis has renewed concern about the risk of psychosis with cannabis.

METHODS

The objective of the WFSBP task force was to review the literature about this relationship.

RESULTS

Converging lines of evidence suggest that exposure to cannabis increases the risk for psychoses ranging from transient psychotic states to chronic recurrent psychosis. The greater the dose, and the earlier the age of exposure, the greater the risk. For some psychosis outcomes, the evidence supports some of the criteria of causality. However, alternate explanations including reverse causality and confounders cannot be conclusively excluded. Furthermore, cannabis is neither necessary nor sufficient to cause psychosis. More likely it is one of the multiple causal components. In those with established psychosis, cannabis has a negative impact on the course and expression of the illness. Emerging evidence also suggests alterations in the endocannabinoid system in psychotic disorders.

CONCLUSIONS

Given that exposure to cannabis and cannabinoids is modifiable, delaying or eliminating exposure to cannabis or cannabinoids, could potentially impact the rates of psychosis related to cannabis, especially in those who are at high risk for developing the disorder.

Molecular Alterations of the Endocannabinoid System in Psychiatric Disorders

The therapeutic benefits of the current medications for patients with psychiatric disorders contrast with a great variety of adverse effects. The endocannabinoid system (ECS) components have gained high interest as potential new targets for treating psychiatry diseases because of their neuromodulator role, which is essential to understanding the regulation of many brain functions. This article reviewed the molecular alterations in ECS occurring in different psychiatric conditions. The methods used to identify alterations in the ECS were also described. We used a translational approach. The animal models reproducing some behavioral and/or neurochemical aspects of psychiatric disorders and the molecular alterations in clinical studies in post-mortem brain tissue or peripheral tissues were analyzed. This article reviewed the most relevant ECS changes in prevalent psychiatric diseases such as mood disorders, schizophrenia, autism, attentional deficit, eating disorders (ED), and addiction. The review concludes that clinical research studies are urgently needed for two different purposes: (1) To identify alterations of the ECS components potentially useful as new biomarkers relating to a specific disease or condition, and (2) to design new therapeutic targets based on the specific alterations found to improve the pharmacological treatment in psychiatry.

The Expanded Endocannabinoid System Contributes to Metabolic and Body Mass Shifts in First-Episode Schizophrenia: A 5-Year Follow-Up Study

Alterations in the expanded endocannabinoid system (eECS) and cell membrane composition have been implicated in the pathophysiology of schizophrenia spectrum disorders. We enrolled 54 antipsychotic (AP)-naïve first-episode psychosis (FEP) patients and 58 controls and applied a targeted metabolomics approach followed by multivariate data analysis to investigate the profile changes in the serum levels of endocannabinoids: 2-arachidonoylglycerol (2-AG) and anandamide, endocannabinoids-like N-acylethanolamines (NAEs: linoleoylethanolamide, oleoylethanolamide, and palmitoylethanolamide), and their dominating lipid precursor’s phosphatidylcholines. Biomolecule profiles were measured at the onset of first-episode psychosis (FEP) and 0.6 years and 5.1 years after the initiation of AP treatment. The results indicated that FEP might be characterized by elevated concentrations of NAEs and by decreased 2-AG levels. At this stage of the disease, the NAE-mediated upregulation of peroxisome proliferator-activated receptors (PPARs) manifested themselves in energy expenditure. A 5-year disease progression and AP treatment adverse effects led to a robust increase in 2-AG levels, which contributed to strengthened cannabinoid (CB1) receptor-mediated effects, which manifested in obesity. Dynamic 2-AG, NAEs, and their precursors in terms of phosphatidylcholines are relevant to the description of the metabolic shifts resulting from the altered eECS function during and after FEP.

Endocannabinoid system in psychotic and mood disorders, a review of human studies

Despite widespread evidence of endocannabinoid system involvement in the pathophysiology of psychiatric disorders, our understanding remains rudimentary. Here we review studies of the endocannabinoid system in humans with psychotic and mood disorders. Postmortem, peripheral, cerebrospinal fluid and in vivo imaging studies provide evidence for the involvement of the endocannabinoid system in psychotic and mood disorders. Psychotic disorders and major depressive disorder exhibit alterations of brain cannabinoid CB1 receptors and peripheral blood endocannabinoids. Further, these changes may be sensitive to treatment status, disease state, and symptom severity. Evidence from psychotic disorder extend to endocannabinoid metabolizing enzymes in the brain and periphery, whereas these lines of evidence remain poorly developed in mood disorders. A paucity of studies examining this system in bipolar disorder represents a notable gap in the literature. Despite a growing body of productive work in this field of research, there is a clear need for investigation beyond the CB1 receptor in order to more fully elucidate the role of the endocannabinoid system in psychotic and mood disorders.

Peripheral Endogenous Cannabinoid Levels Are Increased in Schizophrenia Patients Evaluated in a Psychiatric Emergency Setting

BACKGROUND

The endogenous cannabinoid system mediates the psychoactive effects of cannabis in the brain. It has been argued that this system may play a key role in the pathophysiology of schizophrenia. While some studies have consistently shown that the levels of anandamide, an endogenous cannabinoid ligand, are increased in the cerebrospinal fluid of schizophrenia patients, inconsistent results have been observed in studies measuring anandamide levels in the periphery. Here, we sought to determine if the assessment of peripheral anandamide levels in patients evaluated in a psychiatric emergency setting would show robust increases.

METHODS

One hundred seven patients with a schizophrenia-spectrum disorder from the psychiatric emergency settings of the Institut Universitaire en Santé Mentale de Montréal and 36 healthy volunteers were included in the study. A subsample of thirty patients were assessed at two time points: at the emergency and at their discharge from the hospital. Anxious and depressive symptoms, sleep and substance use were assessed using self-report questionnaires. In addition to anandamide, the levels of oleoylethanolamide (OEA), an anorexigenic fatty-acid ethanolamide, were also measured, since the prevalence of the metabolic syndrome is increased in schizophrenia. Plasma levels of anandamide and OEA were measured using liquid chromatography and mass spectrometry.

RESULTS

Plasma anandamide and OEA levels were significantly increased in schizophrenia patients, relative to controls (Cohen's d=1.0 and 0.5, respectively). Between-group differences remained significant after controlling for metabolic measures. No differences were observed between schizophrenia patients with and without a comorbid substance use disorder at baseline. Importantly, the levels of both endocannabinoids significantly decreased after discharge from the emergency setting.

CONCLUSION

The current results add to the growing body of evidence of endocannabinoid alterations in schizophrenia. The strong elevation of plasma anandamide levels in schizophrenia patients assessed in the psychiatric emergency setting suggests that anandamide and OEA area potential biomarkers of the psychological turmoil associated with this context.

Endocannabinoid System Components as Potential Biomarkers in Psychiatry

The high heterogeneity of psychiatric disorders leads to a lack of diagnostic precision. Therefore, the search of biomarkers is a fundamental aspect in psychiatry to reach a more personalized medicine. The endocannabinoid system (ECS) has gained increasing interest due to its involvement in many different functional processes in the brain, including the regulation of emotions, motivation, and cognition. This article reviews the role of the main components of the ECS as biomarkers in certain psychiatric disorders. Studies carried out in rodents evaluating the effects of pharmacological and genetic manipulation of cannabinoid receptors or endocannabinoids (eCBs) degrading enzymes were included. Likewise, the ECS-related alterations occurring at the molecular level in animal models reproducing some behavioral and/or neuropathological aspects of psychiatric disorders were reviewed. Furthermore, clinical studies evaluating gene or protein alterations in post-mortem brain tissue or in vivo blood, plasma, and cerebrospinal fluid (CSF) samples were analyzed. Also, the results from neuroimaging studies using positron emission tomography (PET) or functional magnetic resonance (fMRI) were included. This review shows the close involvement of cannabinoid receptor 1 (CB1r) in stress regulation and the development of mood disorders [anxiety, depression, bipolar disorder (BD)], in post-traumatic stress disorder (PTSD), as well as in the etiopathogenesis of schizophrenia, attention deficit hyperactivity disorder (ADHD), or eating disorders (i.e. anorexia and bulimia nervosa). On the other hand, recent results reveal the potential therapeutic action of the endocannabinoid tone manipulation by inhibition of eCBs degrading enzymes, as well as by the modulation of cannabinoid receptor 2 (CB2r) activity on anxiolytic, antidepressive, or antipsychotic associated effects. Further clinical research studies are needed; however, current evidence suggests that the components of the ECS may become promising biomarkers in psychiatry to improve, at least in part, the diagnosis and pharmacological treatment of psychiatric disorders.

Measuring Disturbance of the Endocannabinoid System in Psychosis: A Systematic Review and Meta-analysis

IMPORTANCE

The endocannabinoid system (ECS) is a lipid-based endogenous signaling system. Its relevance to psychosis is through the association between cannabis use and the onset and course of illness and through the antipsychotic properties of cannabidiol, a potential ECS enhancer.

OBJECTIVE

To conduct a systematic review and meta-analysis of the blood and cerebrospinal fluid (CSF) measures of the ECS in psychotic disorders.

DATA SOURCES

Web of Science and PubMed were searched from inception through June 13, 2018. The articles identified were reviewed, as were citations to previous publications and the reference lists of retrieved articles.

STUDY SELECTION

Original articles were included that reported blood or CSF measures of ECS activity in patients with psychotic illnesses and in healthy controls.

DATA EXTRACTION AND SYNTHESIS

PRISMA guidelines, independent extraction by multiple observers, and random-effects meta-analysis were used. Heterogeneity was assessed with the I2 index. Sensitivity analyses tested the robustness of the results.

MAIN OUTCOMES AND MEASURES

The clinical relevance of ECS modifications in psychotic disorders was investigated by (1) a quantitative synthesis of the differences in blood and CSF markers of the ECS between patients and healthy controls, and (2) a qualitative synthesis of the association of these markers with symptom severity, stage of illness, and response to treatment.

RESULTS

A total of 18 studies were included. Three individual meta-analyses were performed to identify the differences in ECS markers between people with schizophrenia and healthy controls. Five studies, including 226 patients and 385 controls, reported significantly higher concentrations of anandamide in the CSF of patients than controls (standardized mean difference [SMD], 0.97; 95% CI, 0.67-1.26; P < .001; I2 = 54.8%). In 9 studies, with 344 patients and 411 controls, significantly higher anandamide levels in blood were found in patients, compared with controls (SMD, 0.55; 95% CI, 0.05-1.04; P = .03; I2 = 89.6%). In 3 studies, involving 88 patients and 179 controls, a significantly higher expression of type 1 cannabinoid receptors on peripheral immune cells was reported in patients compared with controls (SMD, 0.57; 95% CI, 0.31-0.84; P < .001; I2 = 0%). Higher ECS tone was found at an early stage of illness in individuals who were antipsychotic naïve or free, and it had an inverse association with symptom severity and was normalized after successful treatment. Moderate to high level of heterogeneity in methods was found between studies.

CONCLUSIONS AND RELEVANCE

Testing clinically relevant markers of the ECS in the blood and CSF of people with psychotic illness appears possible, and these markers provide useful biomarkers for the psychotic disorder; however, not all studies accounted for important variables, such as cannabis use.

TRIAL REGISTRATION

PROSPERO identifier: CRD42018099863.

A systematic review of phytocannabinoid exposure on the endocannabinoid system: Implications for psychosis

Cannabis, the most widely used illicit drug worldwide, produces psychoactive effects through its component cannabinoids, which act on the endocannabinoid system. Research on how cannabinoid exposure affects the endocannabinoid system is limited. Substantial evidence indicates cannabis use as a risk factor for psychosis, and the mechanism(s) by which this is occurring is/are currently unknown. Here, we conduct the first review of the effects of exogenous cannabinoids on the endocannabinoid system in humans with and without psychotic disorders. The most well established finding is the down-regulation of cannabinoid CB1 receptors (CB1R) after chronic and recent cannabis exposure, but it remains uncertain whether this effect is present in cannabis users with schizophrenia. We highlight where cannabis exposure affects the endocannabinoid system in a pattern that may mirror what is seen in psychosis, and how further research can push this field forward. In these times of changing cannabis legislation, research highlighting the biological effects of cannabinoids is greatly needed.

Familial abnormalities of endocannabinoid signaling in schizophrenia

OBJECTIVES

Epidemiological and experimental evidence suggests that the endocannabinoid system plays a pathophysiological role in schizophrenia. This is reflected by elevated cerebrospinal levels of the endocannabinoid anandamide in schizophrenia and its initial prodromal states.

METHODS

We analyzed plasma concentrations of anandamide, 2-arachidonoyl-sn-glycerol, palmitoylethanolamide and oleoylethanolamide from 25 twin pairs discordant for schizophrenia, six discordant for bipolar disorder and eight healthy twin pairs to determine hereditary traits.

RESULTS

Twin pairs discordant for schizophrenia or bipolar disorder had significantly higher levels of anandamide and palmitoylethanolamide compared to healthy twins (both P < 0.002). Non-affected twins discordant for schizophrenia, who developed a psychotic disorder within 5 years follow-up showed lower anandamide (P = 0.042) and 2-arachidonoyl-sn-glycerol levels (P = 0.049) than twins who remained healthy.

CONCLUSIONS

We suggest that the protective upregulation of endocannabinoid signalling reflects either a hereditary trait or mirrors a modulating response to genetically influenced cerebral function involving, e.g., other neurotransmitters or energy metabolism.

Non-Genetic Factors in Schizophrenia

PURPOSE OF REVIEW

We review recent developments on risk factors in schizophrenia.

RECENT FINDINGS

The way we think about schizophrenia today is profoundly different from the way this illness was seen in the twentieth century. We now know that the etiology of schizophrenia is multifactorial and reflects an interaction between genetic vulnerability and environmental contributors. Environmental risk factors such as pregnancy and birth complications, childhood trauma, migration, social isolation, urbanicity, and substance abuse, alone and in combination, acting at a number of levels over time, influence the individual's likelihood to develop the disorder. Environmental risk factors together with the identification of a polygenic risk score for schizophrenia, research on gene-environment interaction and environment-environment interaction have hugely increased our knowledge of the disorder.

Circulating Endocannabinoids: From Whence Do They Come and Where are They Going?

The goal of this review is to summarize studies in which concentrations of circulating endocannabinoids in humans have been examined in relationship to physiological measurements and pathological status. The roles of endocannabinoids in the regulation of energy intake and storage have been well studied and the data obtained consistently support the hypothesis that endocannabinoid signaling is associated with increased consumption and storage of energy. Physical exercise mobilizes endocannabinoids, which could contribute to refilling of energy stores and also to the analgesic and mood-elevating effects of exercise. Circulating concentrations of 2-arachidonoylglycerol are very significantly circadian and dysregulated when sleep is disrupted. Other conditions under which circulating endocannabinoids are altered include inflammation and pain. A second important role for endocannabinoid signaling is to restore homeostasis following stress. Circulating endocannabinoids are stress-responsive and there is evidence that their concentrations are altered in disorders associated with excessive stress, including post-traumatic stress disorder. Although determination of circulating endocannabinoids can provide important information about the state of endocannabinoid signaling and thus allow for hypotheses to be defined and tested, the large number of physiological factors that contribute to their circulating concentrations makes it difficult to use them in isolation as a biomarker for a specific disorder.

Plasma concentrations of oleoylethanolamide and other acylethanolamides are altered in alcohol-dependent patients: effect of length of abstinence

Acylethanolamides are a family of endogenous lipid mediators that are involved in physiological and behavioral processes associated with addiction. Recently, oleoylethanolamide (OEA) has been reported to reduce alcohol intake and relapse in rodents but the contribution of OEA and other acylethanolamides in alcohol addiction in humans is unknown. The present study is aimed to characterize the plasma acylethanolamides in alcohol dependence. Seventy-nine abstinent alcohol-dependent subjects (27 women) recruited from outpatient treatment programs and age-/sex-/body mass-matched healthy volunteers (28 women) were clinically assessed with the diagnostic interview PRISM according to the DSM-IV-TR after blood extraction for quantification of acylethanolamide concentrations in the plasma. Our results indicate that all acylethanolamides were significantly increased in alcohol-dependent patients compared with control subjects (p < 0.001). A logistic model based on these acylethanolamides was developed to distinguish alcohol-dependent patients from controls and included OEA, arachidonoylethanolamide (AEA) and docosatetraenoylethanolamide (DEA), providing a high discriminatory power according to area under the curve [AUC = 0.92 (95%CI: 0.87-0.96), p < 0.001]. Additionally, we found a significant effect of the duration of alcohol abstinence on the concentrations of OEA, AEA and DEA using a regression model (p < 0.05, p < 0.01 and p < 0.001, respectively), which was confirmed by a negative correlation (rho = -0.31, -0.40 and -0.44, respectively). However, acylethanolamides were not influenced by the addiction alcohol severity, duration of problematic alcohol use or diagnosis of psychiatric comorbidity. Our results support the preclinical studies and suggest that OEA, AEA and DEA are altered in alcohol-dependence during abstinence and that might act as potential markers for predicting length of alcohol abstinence.

Sex differences in psychiatric comorbidity and plasma biomarkers for cocaine addiction in abstinent cocaine-addicted subjects in outpatient settings

There are sex differences in the progression of drug addiction, relapse, and response to therapies. Because biological factors participate in these differences, they should be considered when using biomarkers for addiction. In the current study, we evaluated the sex differences in psychiatric comorbidity and the concentrations of plasma mediators that have been reported to be affected by cocaine. Fifty-five abstinent cocaine-addicted subjects diagnosed with lifetime cocaine use disorders (40 men and 15 women) and 73 healthy controls (48 men and 25 women) were clinically assessed with the diagnostic interview "Psychiatric Research Interview for Substance and Mental Disorders." Plasma concentrations of chemokines, cytokines, N-acyl-ethanolamines, and 2-acyl-glycerols were analyzed according to history of cocaine addiction and sex, controlling for covariates age and body mass index (BMI). Relationships between these concentrations and variables related to cocaine addiction were also analyzed in addicted subjects. The results showed that the concentrations of chemokine (C-C motif) ligand 2/monocyte chemotactic protein-1 (CCL2/MCP-1) and chemokine (C-X-C motif) ligand 12/stromal cell-derived factor-1 (CXCL12/SDF-1) were only affected by history of cocaine addiction. The plasma concentrations of interleukin 1-beta (IL-1β), IL-6, IL-10, and tumor necrosis factor-alpha (TNFα) were affected by history of cocaine addiction and sex. In fact, whereas cytokine concentrations were higher in control women relative to men, these concentrations were reduced in cocaine-addicted women without changes in addicted men. Regarding fatty acid derivatives, history of cocaine addiction had a main effect on the concentration of each acyl derivative, whereas N-acyl-ethanolamines were increased overall in the cocaine group, 2-acyl-glycerols were decreased. Interestingly, N-palmitoleoyl-ethanolamine (POEA) was only increased in cocaine-addicted women. The covariate BMI had a significant effect on POEA and N-arachidonoyl-ethanolamine concentrations. Regarding psychiatric comorbidity in the cocaine group, women had lower incidence rates of comorbid substance use disorders than did men. For example, alcohol use disorders were found in 80% of men and 40% of women. In contrast, the addicted women had increased prevalences of comorbid psychiatric disorders (i.e., mood, anxiety, and psychosis disorders). Additionally, cocaine-addicted subjects showed a relationship between the concentrations of N-stearoyl-ethanolamine and 2-linoleoyl-glycerol and diagnosis of psychiatric comorbidity. These results demonstrate the existence of a sex influence on plasma biomarkers for cocaine addiction and on the presence of comorbid psychopathologies for clinical purposes.

Peripheral endocannabinoid system dysregulation in first-episode psychosis

Several hypotheses involving alterations of the immune system have been proposed among etiological explanations for psychotic disorders. The endocannabinoid system (ECS) has a homeostatic role as an endogenous neuroprotective and anti-inflammatory system. Alterations of this system have been associated with psychosis. Cannabis use is a robust risk factor for these disorders that could alter the ECS signalling. In this study, 95 patients with a first episode of psychosis (FEP) and 90 healthy controls were recruited. Protein expression of cannabinoid receptor 2 (CB2), the protein levels of the main endocannabinoid synthesizing enzymes N-acyl phosphatidylethanolamine phospholipase (NAPE) and diacylglycerol lipase (DAGL), and of degradation enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) were determined by western blot analysis in peripheral blood mononuclear cells (PBMCs). Patients with a FEP showed a decreased expression of CB2 and of both endocannabinoids synthesizing enzymes (NAPE and DAGL) in comparison to healthy controls. After controlling for age, gender, body mass index, and cannabis use, NAPE and DAGL expression remained significantly decreased, whereas FAAH and MAGL expression were increased. On the other hand, FEP subjects with history of severe cannabis use showed a larger ECS dysregulation compared with healthy controls. These results indicate an ECS dysregulation in PBMC of FEP patients. The alteration of the ECS presented at the initial phases of psychosis could be contributing to the pathophysiology of the disease and constitutes a possible biomarker of psychotic disorders and an interesting pharmacological target to take into account for therapeutic purposes.

Evaluation of plasma-free endocannabinoids and their congeners in abstinent cocaine addicts seeking outpatient treatment: impact of psychiatric co-morbidity

Cocaine is associated with serious health problems including psychiatric co-morbidity. There is a need for the identification of biomarkers for the stratification of cocaine-addicted subjects. Several studies have evaluated circulating endocannabinoid-related lipids as biomarkers of inflammatory, metabolic and mental disorders. However, little is known in substance use disorders. This study characterizes both free N-acyl-ethanolamines (NAEs) and 2-acyl-glycerols in abstinent cocaine addicts from outpatient treatment programs who were diagnosed with cocaine use disorder (CUD; n = 88), and age-/gender-/body mass-matched healthy control volunteers (n = 46). Substance and mental disorders that commonly occur with substance abuse were assessed by the semi-structured interview 'Psychiatric Research Interview for Substance and Mental Diseases' according to the 'Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision' (DSM-IV-TR) and plasma-free acyl derivatives were quantified by a liquid chromatography-tandem mass spectrometry system. The results indicate that plasma acyl derivatives are altered in abstinent cocaine-addicted subjects with CUD (CUD subjects). While NAEs were found to be increased, 2-acyl-glycerols were decreased in CUD subjects compared with controls. Multivariate predictive models based on these lipids as explanatory variables were developed to distinguish CUD subjects from controls providing high discriminatory power. However, these alterations were not influenced by the DSM-IV-TR criteria for cocaine abuse and dependence as cocaine trait severity measure. In contrast, we observed that some free acyl derivatives in CUD subjects were found to be affected by the diagnosis of some co-morbid psychiatric disorders. Thus, we found that the monounsaturated NAEs were significantly elevated in CUD subjects diagnosed with mood [N-oleoyl-ethanolamine and N-palmitoleoyl-ethanolamine (POEA)] and anxiety (POEA) disorders compared with non-co-morbid CUD subjects. Interestingly, the coexistence of alcohol use disorders did not influence the circulating levels of these free acyl derivatives. In summary, we have identified plasma-free acyl derivatives that might serve as reliable biomarkers for CUD. Furthermore, we found that monounsaturated NAE levels are also enhanced by co-morbid mood and anxiety disorders in cocaine addicts. These findings open the way for the development of new strategies for cocaine addiction diagnosis and treatment.