Clozapine use in patients with schizophrenia and a comorbid substance use disorder: A systematic review

Therapeutic Potential of Cannabis: A Comprehensive Review of Current and Future Applications

Historically, cannabis has been valued for its pain-relieving, anti-inflammatory, and calming properties. Ancient civilizations like the Egyptians, Greeks, and Chinese medicines recognized their therapeutic potential. The discovery of the endocannabinoid system, which interacts with cannabis phytoconstituents, has scientifically explained how cannabis affects the human immune system, including the central nervous system (CNS). This review explores the evolving world of cannabis-based treatments, spotlighting its diverse applications. By researching current research and clinical studies, we probe into how cannabinoids like Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) help to manage conditions ranging from chronic pain, persistent inflammation, cancer, inflammatory bowel disease, and neurological disorders to even viral diseases such as Human Immunodeficiency virus (HIV), SARS-CoV-2. and the emerging monkeypox. The long-term recreational use of cannabis can develop into cannabis use disorder (CUD), and therefore, understanding the factors contributing to the development and maintenance of cannabis addiction, including genetic predisposition, neurobiological mechanisms, and environmental influences, will be timely. Shedding light on the adverse impacts of CUD underscores the importance of early intervention, effective treatment approaches, and public health initiatives to address this complex issue in an evolving landscape of cannabis policies and perceptions.

Rates and Reasons for Clozapine Treatment Interruptions: Impact of the Frequency of Hematologic Monitoring and Cardiac Adverse Events

BACKGROUND

Differing rates and reasons for interruptions of clozapine treatment have been reported globally. This article evaluated the rates and reasons for clozapine therapy interruptions in Australia and explored the impact of the frequency of hematological monitoring on these parameters.

METHODS

Data of the patients who were newly commenced on clozapine at three metropolitan public mental health services in Western Australia over 11 years were retrospectively collated. The rate and reasons for clozapine therapy interruptions and their association with the frequency of hematological monitoring, age, sex, and treatment site were analyzed using parametric, nonparametric, and correlational analyses.

RESULTS

Of the 457 patients whose data were collected, 69.6% had an interruption of treatment with 41.2% of those occurring during the period of mandatory weekly hematological monitoring in the first 18 weeks. Nonadherence (57.4%) and adverse effects (28.8%) were the 2 main reasons for the treatment interruptions. Cardiac issues accounted for the majority of the interruptions (61.8%) due to specified adverse effects, and these occurred significantly more commonly within the first 18 weeks. Location, age, and sex did not predict the possibility of treatment interruptions.

CONCLUSIONS

The high rates of clozapine treatment interruption observed during the period of weekly monitoring point toward the need to address the burden of frequent hematological monitoring for patients. Disproportionately higher rates of interruption due to cardiac adverse effects observed in this study compared with research from non-Australian settings raise the possibility of geographical differences in the adverse effects leading to treatment discontinuation.

Effects of clozapine treatment on the improvement of substance use disorders other than nicotine in individuals with schizophrenia spectrum disorders: A systematic review and meta-analysis

BACKGROUND

Antipsychotic medications are the mainstay of treatment for schizophrenia and are associated with a reduction in psychiatric hospitalization and overall mortality. Some evidence suggest that antipsychotic medications might have a varying effect on the improvement of comorbid substance use disorders (SUDs), with clozapine showing more favorable outcomes.

AIM

We systematically reviewed all available evidence on effects of clozapine on the improvement of SUDs other than nicotine.

METHODS

Electronic searches of MEDLINE, Embase, PsycINFO, and CINHAL were conducted up to March 1, 2022. Studies of any methodological design involving two concepts: (1) clozapine and (2) SUD terms (excluding nicotine) were included. For SUD outcomes with three or more comparative studies with available raw data meta-analysis was performed. SUD outcomes not meeting criteria for meta-analysis were described qualitatively. Risk of bias was examined using "Downs and Black," and "Q-Coh" instruments.

RESULTS

The majority of individuals in the included 31 studies were male and of European ancestry. Abstinence was the most common outcome. Most of the studies were of low-to-moderate quality, and none of the studies met all the quality criteria. Pooled findings from four observational studies in samples of patients with predominantly comorbid alcohol use disorder showed that clozapine treatment is associated with significantly higher odds of remaining abstinent. In addition clozapine was associated with decreased odds of psychiatric hospitalization in all but one observational study.

CONCLUSIONS

Our systematic review and meta-analysis builds upon previous reviews, and it suggests the association of clozapine treatment with significantly higher odds of remaining abstinent from substance use and decreased likelihood of psychiatric hospitalization, compared with continuing treatment with other antipsychotic medications. Still, the validity of this association needs greater exploration and providing recommendations for the utility of clozapine in individuals without treatment-resistant psychosis and comorbid SUDs would be premature.

Prevention of suicide by clozapine in mental disorders: systematic review

BACKGROUND

Previous research has investigated the efficacy of clozapine in reducing suicidality in patients with schizophrenia and schizoaffective disorder. We aimed to systematically review published evidence, including studies concerning clozapine administration to treat: (a) refractory suicidality in other mental disorders, including bipolar disorder and borderline and other personality disorders; and (b) refractory cases of non-suicidal self-injury.

METHOD

We performed a PUBMED-search (last day: July 17, 2022) of English-language studies, combining the keywords "clozapine", "suicidality", and "suicide" with various psychopathological terms (e.g. "schizophrenia"). All duplications were eliminated.

RESULTS

Fifty-one studies were eligible for inclusion in the review. Most studies suggest a superior anti-suicide effect of clozapine in schizophrenia/schizoaffective disorder, compared to other antipsychotics, or no antipsychotic therapy, which is not due to the close monitoring of patients for blood dyscrasias. No consensus exists as to whether other antipsychotic drugs share this effect. Discontinuation of clozapine is associated with increases in suicidality. Reductions in refractory suicidality/NSSI are observed in clozapine-treated patients with bipolar disorder or borderline personality disorder, but the evidence is limited. Potential biological underpinnings of the anti-suicide effect of clozapine include its unique profile of modulation of brain neurotransmitters; its non-selectivity for neurotransmitter receptors; specific genetic and hormonal factors; effects on neuroinflammation; and ability to elicit epileptiform activity.

CONCLUSION

The superior anti-suicide effect of clozapine in schizophrenia/schizoaffective disorder patients is well established. It may have a role in severe and refractory cases of suicidality and non-suicidal self-injury in patients with bipolar disorder or borderline personality disorder, but the level and quality of supporting evidence is limited.

The role of alcohol intake in the pharmacogenetics of treatment with clozapine

Clozapine (CLZ) is an atypical antipsychotic reserved for patients with refractory psychosis, but it is associated with a significant risk of severe adverse reactions (ADRs) that are potentiated with the concomitant use of alcohol. Additionally, pharmacogenetic studies have explored the influence of several genetic variants in CYP450, receptors and transporters involved in the interindividual response to CLZ. Herein, we systematically review the current multiomics knowledge behind the interaction between CLZ and alcohol intake, and how its concomitant use might modulate the pharmacogenetics. CYP1A2*1F, *1C and other alleles not yet discovered could support a precision medicine approach for better therapeutic effects and fewer CLZ ADRs. CLZ monitoring systems should be amended and include alcohol intake to protect patients from severe CLZ ADRs.

Antipsychotic-Associated Weight Gain and Clinical Improvement Under Clozapine Treatment

BACKGROUND

Antipsychotic-associated weight gain is a common adverse effect with several negative outcomes in the clinical evolution of patients, which might also affect patients' self-identity from physical appearance and imply treatment discontinuation. However, recent research has drawn attention to an unexpected clinical improvement associated with weight gain, mostly in patients under treatment with clozapine or olanzapine.

METHODS

Twenty-three treatment-resistant psychosis patients initiating clozapine were evaluated. Longitudinal psychopathological assessment through the Positive and Negative Syndrome Scale (PANSS) and anthropometric evaluation were performed at baseline, week 8, and 18.

RESULTS

Body mass index (BMI) change during clozapine treatment was associated with clinical improvement measured with PANSS total score at week 8 (P = 0.021) while showed a trend at week 18 (P = 0.058). The PANSS general score was also associated with weight gain at week 8 (P = 0.022), whereas negative subscale score showed a trend at week 8 (P = 0.088) and was associated between week 8 and 18 (P = 0.018). Sex differences applied at week 8 for PANSS total score, where clinical improvement was significantly associated with BMI in male subjects (P = 0.024). We also stratified for time to initiate clozapine, finding significant associations in negative symptom at week 8 (P = 0.023) and week 18 (P = 0.003) for subjects, which started clozapine after 3 years of illness.

CONCLUSIONS

Our results suggest that in subjects initiating clozapine, clinical improvement is associated with BMI increase, mostly in negative symptom and in patients after 3 years of antipsychotic use. Our findings were already described in the preantipsychotic era, suggesting some pathophysiological mechanism underlying both conditions.

Unraveling the Association Between Schizophrenia and Substance Use Disorder-Predictors, Mechanisms and Treatment Modifications: A Systematic Review

Individuals with schizophrenia are particularly vulnerable to substance abuse problems. Comorbidity with substance use disorders (SUDs) frequently results in early death and increased dysfunction observed in schizophrenia. This dual diagnosis can be explained through multiple general mechanisms. Tobacco, alcohol, cannabis, and cocaine are substances widely used by individuals with schizophrenia. This study highlights the predictors, mechanisms responsible for the relationship between substance use disorder and schizophrenia and how it can help with the treatment of both disorders. The publications were rigorously reviewed after being found in multiple databases. The study's inclusion criteria were research published within the last five years, publications written in English, full-text availability, and human studies. A total of ten papers were selected for examination from a total of 9,106 articles found using the search method across several databases. This study follows the rules listed within the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist 2009. The information gathered from these published studies was used to investigate the elements that contribute to the link between schizophrenia and substance abuse. Here, we evaluate a close relationship between schizophrenia and substance use disorders. The articles studied exhibit a bidirectional association between the two disorders in most individuals. From our analysis, the comorbidity between the two disorders is partially due to shared polygenic liability. Individuals with schizophrenia have dysfunctional Mesocorticolimbic brain reward circuits indicating a history of substance use. An underlying genetic vulnerability to schizophrenia may be triggered by extensive cannabis usage at a young age. A combination of psychological and pharmacological interventions for both disorders can significantly improve the outcome.

Investigating Predictors of Clozapine Response in Adolescents with Schizophrenia and Schizoaffective Disorder

Objectives: We aimed to determine the clinical predictors of clozapine response in patients with early-onset schizophrenia (EOS)/schizoaffective disorder and the effect of substance use disorder (SUD) on treatment outcomes. Methods: Medical records of patients with treatment-resistant EOS receiving clozapine were identified for data analysis dated between January 2015 and April 2020. Patients on clozapine were followed in an inpatient unit of a tertiary care mental health hospital. Using the Positive and Negative Symptom Scale (PANSS), ≥30% reduction was defined as the response criteria after clozapine treatment. Results: Of 50 subjects (age: 16.3 ± 1.3 years, 36.0% female), 22 subjects (44.0%) met the defined response criteria. Clozapine responder (CLZ-R) and clozapine nonresponder (CLZ-NR) groups were similar regarding age at illness onset, sex, and duration of untreated psychosis. The CLZ-R group had higher baseline positive PANSS scores (24.8 ± 8.1 vs. 17.1 ± 6.6, p = 0.001, d = 1.0) and total PANSS scores (94.8 ± 17.2 vs. 80.1 ± 19.8, p = 0.008, d = 0.8) compared with the CLZ-NR counterparts. The duration of hospital stay was longer in the CLZ-NR group (122.3 ± 48.2 vs. 87.3 ± 36.2 days, p = 0.007). Among 32 male patients, the presence of SUD (n = 9, 28.1%) was associated with a less reduction in total PANSS scores (F = 7.5, p = 0.010) and higher levels of positive symptoms at the end of the treatment (12.8 ± 4.1 vs. 18.8 ± 7.4, p = 0.006, d = 1.0). Synthetic cannabinoids were the most common substance type used among males with treatment-refractory EOS (25.0%). Conclusions: Our results did not support the role of sociodemographic variables in clozapine response. Positive symptoms and SUD yielded a prognostic value in patients receiving clozapine.

A systematic review of longitudinal studies investigating the impact of cannabis use in patients with psychotic disorders

Introduction: Research has established a link between cannabis use and adverse psychotic outcomes in psychosis patients. However, we have yet to determine if this relationship is maintained when controlling for important confounding variables. The following systematic review aims to investigate if the association between cannabis use and psychotic outcomes is preserved when accounting for important confounders, and if discontinued use mitigates any potential negative impacts.Areas covered: The authors conducted an exhaustive search of the MEDLINE database and Google Scholar to identify articles pertaining to the systematic review. Thirty-three articles were retained for meeting the eligibility criteria.Expert opinion: The evidence confirms an overarching pattern of negative psychotic outcomes of cannabis intake in psychosis populations, even when accounting for crucial confounders. Psychosis patients should be informed with evidence-based health information regarding the effects of cannabis use. Clinicians should systematically evaluate cannabis intake patterns in psychosis patients and offer intervention services geared toward reducing problematic consumption. Researchers should record confounding factors in a more systematic manner in future longitudinal investigations while paying careful attention to the potency and dose-response effects of the ingested cannabis. Deciders will need to investigate the impact of cannabis regulations on psychosis populations.

The prevalence of agranulocytosis and related death in clozapine-treated patients: a comprehensive meta-analysis of observational studies

BACKGROUND

Clozapine treatment increases the risk of agranulocytosis, but findings on the epidemiology of agranulocytosis have been inconsistent. This meta-analysis examined the prevalence of agranulocytosis and related death in clozapine-treated patients.

METHODS

A literature search in the international (PubMed, PsycINFO, and EMBASE) and Chinese (WanFang, Chinese National Knowledge Infrastructure, and Sinomed) databases was conducted. Prevalence estimates of agranulocytosis and related death in clozapine-treated patients were synthesized with the Comprehensive Meta-Analysis program using the random-effects model.

RESULTS

Thirty-six studies with 260 948 clozapine-treated patients published between 1984 and 2018 were included in the meta-analysis. The overall prevalence of agranulocytosis and death caused by agranulocytosis were 0.4% (95% CI 0.3-0.6%) and 0.05% (95% CI 0.03-0.09%), respectively. The prevalence of agranulocytosis was moderated by sample size, study quality, year of publication, and that of data collection.

CONCLUSIONS

The prevalence of clozapine-associated agranulocytosis is low. Agranulocytosis-related death appears rare.

Functioning and cognitive characteristics of clozapine users referred to psychosocial rehabilitation centers: A REHABase cohort study

OBJECTIVES

To explore whether clozapine users have specific rehabilitation needs compared to users of other antipsychotics.

METHODS

The study was performed using the REHABase collecting data on persons referred to a French network of psychosocial rehabilitation centers. It was restricted to persons with schizophrenia spectrum disorder using antipsychotics. Multivariate analyses were used to compare baseline functioning and cognitive characteristics in clozapine users vs. users of other antipsychotics.

RESULTS

Of the 675 patients identified in the REHABase, one out of ten (n = 70) used clozapine. Compared to users of other antipsychotics, clozapine users had been more frequently hospitalized in psychiatry and presented less frequently with psychoactive substance use. Functional measures did not significantly differ between the two groups. Clozapine users had poorer short-term verbal memory performance than users of other antipsychotics and did not differ on executive performance.

CONCLUSION

Clozapine users may reach a recovery level comparable to that obtained in persons without treatment-resistant schizophrenia. In order to reduce the negative impact of memory deficits on the recovery process of clozapine users, it is necessary to optimize their psychotropic treatment and to promote their access to cognitive remediation programs addressing their specific needs.

Total and Differential White Blood Cell Counts, Cocaine, and Marijuana Use in Patients With Schizophrenia

Schizophrenia is associated with blood inflammatory marker abnormalities. Illicit drug use, which is common in schizophrenia, may modulate inflammatory marker levels. We examined effects of marijuana and cocaine use on white blood cell (WBC) counts in acutely ill, hospitalized patients with schizophrenia using a within-subjects and between-groups design. Mean total and differential WBC counts were first compared in acutely ill patients with schizophrenia for hospitalizations with and without either marijuana (n = 18) or cocaine (n = 24) use. Mean total and differential WBC counts were then compared between patients with schizophrenia with either marijuana or cocaine use and patients with a negative urine drug screen (UDS; n = 43). Patients with schizophrenia had significantly higher total WBC, lymphocytes, and monocytes during hospitalizations with (vs. without) cocaine use. Patients with cocaine use also had significantly higher monocytes and eosinophils than those with a negative UDS. Our findings suggest that substance use, particularly of cocaine, may modulate inflammatory marker levels in acutely ill, hospitalized patients with schizophrenia.

Treatment of substance use disorders with co-occurring severe mental health disorders

PURPOSE OF REVIEW

To provide an update of treatment for substance use in patients with co-occurring substance use disorders (SUD) and mental health disorders (dual diagnosis) with a focus on both pharmacological and psychosocial interventions.

RECENT FINDINGS

A total of 1435 abstracts were identified, of which we selectively reviewed 43 for this narrative review. There is emerging evidence, both clinical and neurobiological, that clozapine is a more efficacious antipsychotic in treatment of individuals with schizophrenia and SUD. The use of depot atypical antipsychotic paliperidone palmitate in this population is also promising. Although valproate remains the treatment of choice in individuals with bipolar disorder and SUD, present evidence suggests that lithium and quetiapine may not be effective in this population. Naltrexone is the most effective anticraving agent in individuals with severe mental illness (SMI) and comorbid alcohol use disorders. The use of opioid substitution therapy in individuals with SMI and comorbid opioid use disorders is also associated with favorable outcomes. Varenicline shows promise in patients with SMI who smoke tobacco. Psychosocial interventions should be instituted early in the course of treatment. They should ideally be high intensity and based on established therapies used for SUD.

SUMMARY

The paucity of systematic studies in individuals with co-occurring mental health disorders and SUD remains a concern, given the enormous burden that they pose. However, there are a number of studies which have evaluated interventions, both psychosocial and pharmacological, which show promise and can guide clinical practice. VIDEO ABSTRACT: http://links.lww.com/YCO/A49.