Higher Plasma Drug Concentration in Clozapine-treated Schizophrenic Patients With Side Effects of Obsessive/Compulsive Symptoms

A brief history of clozapine use in Taiwan

Blood concentrations of clozapine in Taiwanese patients appeared approximately 30-50 % higher than that from Caucasian patients, and women possessed a higher blood levels. Fluvoxamine was reported to increase the clozapine levels, reduce clozapine-related weight gain and metabolic disturbances, and improved general psychopathology. Clothiapine, a chemical structure analogue of clozapine, showed potential of benefitting patients who are unsuitable for clozapine treatment in Taiwan. Obsessive/compulsive symptom (OCS) is a common side effect of clozapine. Concentrations of clozapine were remarkably higher in patients with OCS than in those without. In conclusion, clozapine is a widely used in patients with schizophrenia in Taiwan.

Polygenetic risk scores and phenotypic constellations of obsessive-compulsive disorder in clozapine-treated schizophrenia

Obsessive-compulsive symptoms (OCS) are frequently observed in individuals with schizophrenia (SCZ) treated with clozapine (CLZ). This study aimed to analyze prevalence of OCS and obsessive-compulsive disorder (OCD) in this subgroup and find possible correlations with different phenotypes. Additionally, this is the first study to examine polygenetic risk scores (PRS) in individuals with SCZ and OCS. A multicenter cohort of 91 individuals with SCZ who were treated with CLZ was recruited and clinically and genetically assessed. Symptom severity was examined using the Positive and Negative Symptom Scale (PANSS), Clinical Global Impression Scale (CGI), the Calgary Depression Scale for Schizophrenia (CDSS), Global Assessment of Functioning Scale (GAF) and Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Participants were divided into subgroups based on phenotypic OCS or OCD using Y-BOCS scores. Genomic-wide data were generated, and PRS analyses were performed to evaluate the association between either phenotypic OCD or OCS severity and genotype-predicted predisposition for OCD, SCZ, cross-disorder, and CLZ/norclozapine (NorCLZ) ratio, CLZ metabolism and NorCLZ metabolism. OCS and OCD were frequent comorbidities in our sample of CLZ-treated SCZ individuals, with a prevalence of 39.6% and 27.5%, respectively. Furthermore, the Y-BOCS total score correlated positively with the duration of CLZ treatment in years (r = 0.28; p = 0.008) and the PANSS general psychopathology subscale score (r = 0.23; p = 0.028). A significant correlation was found between OCD occurrence and PRS for CLZ metabolism. We found no correlation between OCS severity and PRS for CLZ metabolism. We found no correlation for either OCD or OCS and PRS for OCD, cross-disorder, SCZ, CLZ/NorCLZ ratio or NorCLZ metabolism. Our study was able to replicate previous findings on clinical characteristics of CLZ-treated SCZ individuals. OCS is a frequent comorbidity in this cohort and is correlated with CLZ treatment duration in years and PANSS general psychopathology subscale score. We found a correlation between OCD and PRS for CLZ metabolism, which should be interpreted as incidental for now. Future research is necessary to replicate significant findings and to assess possible genetic predisposition of CLZ-treated individuals with SCZ to OCS/OCD. Limitations attributed to the small sample size or the inclusion of subjects on co-medication must be considered. If the association between OCD and PRS for CLZ metabolism can be replicated, it should be further evaluated if CYP1A2 alteration, respectively lower CLZ plasma level, is relevant for OCD development.

Evidence for Therapeutic Drug Monitoring of Atypical Antipsychotics

Second-generation antipsychotics (SGAs), also known as atypical antipsychotics, are a newer class of antipsychotic drugs used to treat schizophrenia, bipolar disorder, and related psychiatric conditions. The plasma concentration of antipsychotic drugs is a valid measure of the drug at its primary target structure in the brain, and therefore determines the efficacy and safety of these drugs. However, despite the well-known high variability in pharmacokinetics of these substances, psychiatric medication is usually administered in uniform dosage schedules. Therapeutic drug monitoring (TDM), as the specific method that can help personalised medicine in dose adjustment according to the characteristics of the individual patient, minimizing the risk of toxicity, monitoring adherence, and increasing cost-effectiveness in the treatment, thus seems to be an elegant tool to solve this problem. Non-response to therapeutic doses, uncertain adherence to medication, suboptimal tolerability, or pharmacokinetic drug-drug interactions are typical indications for TDM of SGAs. This review aims to summarize an overview of the current knowledge and evidence of the possibilities to tailor the dosage of selected SGAs using TDM, including the necessary pharmacokinetic parameters for personalised pharmacotherapy.

A flexible dose-response modeling framework based on continuous toxicity outcomes in phase I cancer clinical trials

BACKGROUND

The past few decades have seen remarkable developments in dose-finding designs for phase I cancer clinical trials. While many of these designs rely on a binary toxicity response, there is an increasing focus on leveraging continuous toxicity responses. A continuous toxicity response pertains to a quantitative measure represented by real numbers. A higher value corresponds not only to an elevated likelihood of side effects for patients but also to an increased probability of treatment efficacy. This relationship between toxicity and dose is often nonlinear, necessitating flexibility in the quest to find an optimal dose.

METHODS

A flexible, fully Bayesian dose-finding design is proposed to capitalize on continuous toxicity information, operating under the assumption that the true shape of the dose-toxicity curve is nonlinear.

RESULTS

We conduct simulations of clinical trials across varying scenarios of non-linearity to evaluate the operational characteristics of the proposed design. Additionally, we apply the proposed design to a real-world problem to determine an optimal dose for a molecularly targeted agent.

CONCLUSIONS

Phase I cancer clinical trials, designed within a fully Bayesian framework with the utilization of continuous toxicity outcomes, offer an alternative approach to finding an optimal dose, providing unique benefits compared to trials designed based on binary toxicity outcomes.

Obsessive-compulsive symptoms and disorder in clozapine-treated schizophrenia

BACKGROUND

Obsessive-compulsive symptoms (OCS) and obsessive-compulsive disorder (OCD) are commonly reported in patients with schizophrenia. Furthermore, the use of clozapine in treatment-resistant schizophrenia has been thought to induce or aggravate these disorders. To date, there is a paucity of research regarding the prevalence and associated factors. Hence, this study aims to report the prevalence of OCS and OCD, and examine potential risk factors, in clozapine-treated schizophrenia.

METHODS

This is a cross-sectional study conducted in the only tertiary hospital for psychiatric patients in Singapore. In total, 162 patients on a stable dose of clozapine were recruited for this study; 159 patients with a diagnosis of schizophrenia or schizoaffective disorder were included in the current analysis. Sociodemographic, clinical and treatment factors were analysed to identify factors associated with OCS and OCD.

RESULTS

The prevalence of OCS and OCD is 21.4% and 12.6% respectively. Factors associated with OCS include younger age (OR:0.96, p=0.033) and younger age of onset of psychosis (OR:0.92, p=0.017). There were no significant factors associated with OCD. However, in an analysis of both OCS and/or OCD, factors associated include younger age (OR:0.96, p=0.027) and younger age of onset of psychosis (OR:0.91, p=0.016). Severity of psychotic illness and Clozapine dose were not associated with OCS or OCD in clozapine-treated schizophrenia.

DISCUSSION & CONCLUSIONS

Our results suggest a high prevalence of OCS and OCD in clozapine-treated schizophrenia which clinicians should routinely screen for. Further research is warranted to establish the link between the factors identified in this study and OCS/OCD in clozapine-treated schizophrenia.

The Neurobiological Underpinnings of Obsessive-Compulsive Symptoms in Psychosis, Translational Issues for Treatment-Resistant Schizophrenia

Almost 25% of schizophrenia patients suffer from obsessive-compulsive symptoms (OCS) considered a transdiagnostic clinical continuum. The presence of symptoms pertaining to both schizophrenia and obsessive-compulsive disorder (OCD) may complicate pharmacological treatment and could contribute to lack or poor response to the therapy. Despite the clinical relevance, no reviews have been recently published on the possible neurobiological underpinnings of this comorbidity, which is still unclear. An integrative view exploring this topic should take into account the following aspects: (i) the implication for glutamate, dopamine, and serotonin neurotransmission as demonstrated by genetic findings; (ii) the growing neuroimaging evidence of the common brain regions and dysfunctional circuits involved in both diseases; (iii) the pharmacological modulation of dopaminergic, serotoninergic, and glutamatergic systems as current therapeutic strategies in schizophrenia OCS; (iv) the recent discovery of midbrain dopamine neurons and dopamine D1- and D2-like receptors as orchestrating hubs in repetitive and psychotic behaviors; (v) the contribution of N-methyl-D-aspartate receptor subunits to both psychosis and OCD neurobiology. Finally, we discuss the potential role of the postsynaptic density as a structural and functional hub for multiple molecular signaling both in schizophrenia and OCD pathophysiology.

Second to none: rationale, timing, and clinical management of clozapine use in schizophrenia

Despite its enduring relevance as the single most effective and important evidence-based treatment for schizophrenia, underutilization of clozapine remains considerable. To a substantial degree, this is attributable to a reluctance of psychiatrists to offer clozapine due to its relatively large side-effect burden and the complexity of its use. This underscores the necessity for continued education regarding both the vital nature and the intricacies of clozapine treatment. This narrative review summarizes all clinically relevant areas of evidence, which support clozapine's wide-ranging superior efficacy - for treatment-resistant schizophrenia (TRS) and beyond - and make its safe use eminently feasible. Converging evidence indicates that TRS constitutes a distinct albeit heterogeneous subgroup of schizophrenias primarily responsive to clozapine. Most importantly, the predominantly early onset of treatment resistance and the considerable decline in response rates associated with its delayed initiation make clozapine an essential treatment option throughout the course of illness, beginning with the first psychotic episode. To maximize patients' benefits, systematic early recognition efforts based on stringent use of TRS criteria, a timely offer of clozapine, thorough side-effect screening and management as well as consistent use of therapeutic drug monitoring and established augmentation strategies for suboptimal responders are crucial. To minimize permanent all-cause discontinuation, re-challenges after neutropenia or myocarditis should be considered. Owing to clozapine's unique efficacy, comorbid conditions including substance use and most somatic disorders should not dissuade but rather encourage clinicians to consider clozapine. Moreover, treatment decisions need to be informed by the late onset of clozapine's full effects, which for reduced suicidality and mortality rates may not even be readily apparent. Overall, the singular extent of its efficacy combined with the high level of patient satisfaction continues to distinguish clozapine from all other available antipsychotics.

A diffusion tensor imaging study in schizophrenia patients with clozapine induced obsessive compulsive symptoms

OBJECTIVE

The aim of this study was to evaluate brain connectivity by diffusion tensor imaging (DTI) in schizophrenia patients with clozapine-induced obsessive compulsive symptoms (OCS).

METHODS

Eighteen schizophrenia patients, nine of which had clozapine-induced OCS (Clz-OCS (+)), 9 without OCS (Clz-OCS (-)) and 9 healthy controls were included. Psychopathology was evaluated with Positive and Negative Syndrome Scale and Yale-Brown Obsession and Compulsion Scale in the patient groups. All groups were assesed with neurocognitive tests and DTI.

RESULTS

Tract-Based Spatial Statistics based comparison of DTI revealed lower fractional anisotropy in the genu of corpus callosum (CC), right cingulum, left frontal white matter (WM) in the Clz-OCS (+) group, compared to controls. Fractional anisotropy was found to be lower in the bilateral occipital WM and higher in the bilateral medial temporal regions, anterior limb of internal capsule, cingulum, frontoparietal peripheral WM, right external capsule and genu of CC in Clz-OCS (+) patients compared to Clz-OCS (-).

CONCLUSIONS

WM integrity in several pathways such as cortico-striato-thalamo-cortical circuitry and orbito-frontal tracts seems to be affected differently in patients with Clz-OCS (+). Different neuroplastic effects of clozapine leading to occurrence of OCS in a subgroup of patients is possible, and needs further evaluation by longitudinal follow-up studies.

Adverse Drug Reactions in Relation to Clozapine Plasma Levels: A Systematic Review

Clozapine is the gold standard for treatment-resistant schizophrenia. Serious and even life-threatening adverse effects, mostly granulocytopenia, myocarditis, and constipation, are of great clinical concern and constitute a barrier to prescribing clozapine, thus depriving many eligible patients of a lifesaving treatment option. Interestingly, clozapine presents variable pharmacokinetics affected by numerous parameters, leading to significant inter- and intra-individual variation. Therefore, therapeutic drug monitoring of plasma clozapine levels confers a significant benefit in everyday clinical practice by increasing the confidence of the prescribing doctor to the drug and the adherence of the patient to the treatment, mainly by ensuring effective treatment and limited dose-related side effects. In the present systematic review, we aimed at identifying how a full range of adverse effects relates to plasma clozapine levels, using the Jadad grading system for assessing the quality of the available clinical evidence. Our findings indicate that EEG slowing, obsessive-compulsive symptoms, heart rate variability, hyperinsulinemia, metabolic syndrome, and constipation correlate to plasma clozapine levels, whereas QTc, myocarditis, sudden death, leucopenia, neutropenia, sialorrhea, are rather unrelated. Rapid dose escalation at the initiation of treatment might contribute to the emergence of myocarditis, or leucopenia. Strategies for managing adverse effects are different in these conditions and are discussed accordingly.

A nationwide nested case-control study of new-onset obsessive-compulsive disorder following antipsychotics use in schizophrenia

OBJECTIVE

A substantial proportion of patients with schizophrenia suffer from comorbid obsessive-compulsive disorder (OCD) possibly associated with antipsychotics. However, little is known about the comparative risks of the antipsychotics. The present study aimed to investigate the risk of new-onset OCD following the initiation of different antipsychotic medications for schizophrenia relative to haloperidol.

METHODS

Using the Korean national claims data, patients aged 15-60 years newly diagnosed with schizophrenia between 2010 and 2018 were identified. Of the 47,808 patients with schizophrenia treated with nine commonly prescribed antipsychotics, 775 new-onset OCD patients were matched to 3,100 patients without OCD using nested case-control design with 1:4 case-control matching based on the sex, age of index date, date of schizophrenia diagnosis, observation period, locations of medical institutions, and level of medical facilities. Using multivariable conditional logistic regression analysis, odd ratios (ORs) for new-onset OCD comparing each antipsychotic agent relative to haloperidol were computed.

RESULTS

The risk for new-onset OCD during treatment with clozapine was significantly higher than that with haloperidol (adjusted OR 2.86; 95% confidence interval [1.63-5.03]). The risks for new-onset OCD with other antipsychotics were not significantly different from that with haloperidol. In subgroup analysis, the early and intermediate, but not late-onset schizophrenia group showed significant risk for OCD associated with clozapine use.

CONCLUSION

The present findings, based on real-world national representative data, provide reliable evidence for the risk of new-onset OCD in patients with schizophrenia receiving clozapine at a population level.

High-Dose Fluvoxamine Augmentation to Clozapine in Treatment-Resistant Psychosis

BACKGROUND

Although clozapine is the gold standard for treatment-resistant schizophrenia, more than 30% of patients remain unresponsive to clozapine monotherapy and may benefit from augmentation strategies. Fluvoxamine augmentation of clozapine may be beneficial in treatment resistance because of pharmacokinetic interactions, allowing for lower clozapine dosages with higher clozapine serum levels and an increased clozapine-to-norclozapine ratio, which can modify adverse effects. An augmentation strategy using higher fluvoxamine doses may also improve persistent negative, anxiety, and obsessive-compulsive symptoms through fluvoxamine's serotonergic activity.

METHODS

Through chart review, we identified 4 cases of patients with treatment-resistant psychosis who underwent high-dose fluvoxamine augmentation of clozapine to target residual negative symptoms, refractory psychosis, anxiety, and obsessive-compulsive symptoms.

FINDINGS

This augmentation strategy continued in 2 patients after discharge who showed clinical improvement without significant adverse effects. Two patients experienced adverse effects that led to the fluvoxamine discontinuation. Despite the fact that fluvoxamine augmentation led to symptom improvement in only 2 patients, all patients achieved high serum clozapine levels. Hematologic parameters were monitored in all patients, and no abnormalities were observed. No severe adverse effects of clozapine were experienced.

CONCLUSIONS

Although high variability of responses and adverse effects were observed during fluvoxamine augmentation to clozapine, this strategy was successful in increasing clozapine serum levels. Through fluvoxamine's serotonergic effects, this strategy may confer benefit to residual negative, obsessive, and anxiety symptoms. Limitations of this case series include the retrospective nature, absence of controls, diversity of diagnoses, multiple interventions in each patient, and lack of masked raters.

Clinical risk factors, phenomenology and the impact of clozapine induced obsessive compulsive symptoms

The aim of this study was to investigate the clinical risk factors, phenomenology and the impact of clozapine induced obsessive-compulsive symptoms (OCS) in patients with schizophrenia. One hundred twenty-two patients receiving clozapine treatment for at least 6 weeks were assessed with Structured Clinical Interview for Axis-I Disorders for DSM-IV, Positive and Negative Syndrome Scale, Yale-Brown Obsessive Compulsive Scale and Checklist, Calgary Depression Scale, Clinical Global Impression Scale and WHO-Disability Assessment Schedule-II. Information about past and current clinical status were gathered through clinical interviews and medical records. With clozapine 44.3% of the patients had de novo OCS, 33.6% had OCS both before and after clozapine, 21.3% didn't report any OCS. Clozapine doses, clozapine and norclozapine plasma levels were not significantly different. Severity of OCS was affected by clozapine and norclozapine plasma levels, and correlated with increased disability. Obsessions were less in clozapine induced OCS group, and compulsions, especially of checking subtypes, were predominant, compared to the group with prior history of OCS, who reported a significant increase in checking compulsion after clozapine treatment. Clozapine induced OCS should be considered during cost/benefit assessment of clozapine treatment, and understanding the risk factors and its different phenomenology may shed light into the underlying mechanisms.

Relationship between clozapine dose and severity of obsessive-compulsive symptoms

Evidence supports the fact that clozapine can induce stressful obsessive-compulsive symptoms (OCS). Although clozapine's robust inhibition of serotonergic neurotransmission is believed to be a key mechanism underlying clozapine-induced OCS, the exact mechanism(s) are not fully understood. Intuitively, it is reasonable to believe that the dose of clozapine is likely related to emergent OCS severity. However, there is conflicting evidence where both positive and inverse relationships have been demonstrated between clozapine dose and emergent OCS severity. Upon examination of clozapine's receptor profile, in particular its affinity for 5-HT_2A and D₂ receptors, we hypothesize that there is a biphasic relationship between clozapine dose and emergent OCS severity. We present here a preliminary analysis of published cases in the literature to support our hypothesis.

Impact of smoking behavior on clozapine blood levels - a systematic review and meta-analysis

OBJECTIVE

Tobacco smoking significantly impacts clozapine blood levels and has substantial implications on individual efficacy and safety outcomes. By investigating differences in clozapine blood levels in smoking and non-smoking patients on clozapine, we aim to provide guidance for clinicians how to adjust clozapine levels for patients on clozapine who change their smoking habits.

METHODS

We conducted a meta-analysis on clozapine blood levels, norclozapine levels, norclozapine/clozapine ratios, and concentration to dose (C/D) ratios in smokers and non-smokers on clozapine. Data were meta-analyzed using a random-effects model with sensitivity analyses on dose, ethnic origin, and study quality.

RESULTS

Data from 23 studies were included in this meta-analysis with 21 investigating differences between clozapine blood levels of smokers and non-smokers. In total, data from 7125 samples were included for the primary outcome (clozapine blood levels in ng/ml) in this meta-analysis. A meta-analysis of all between-subject studies (N = 16) found that clozapine blood levels were significantly lower in smokers compared with non-smokers (Standard Mean Difference (SMD) -0.39, 95% confidence interval (CI) -0.55 to -0.22, P < 0.001, I²  = 80%). With regard to the secondary outcome, C/D ratios (N = 16 studies) were significantly lower in the smoker group (n = 645) compared with the non-smoker group (n = 813; SMD -0.70, 95%CI -0.84 to -0.56, P < 0.00001, I²  = 17%).

CONCLUSION

Smoking behavior and any change in smoking behavior is associated with a substantial effect on clozapine blood levels. Reductions of clozapine dose of 30% are recommended when a patient on clozapine stops smoking. Reductions should be informed by clozapine steady-state trough levels and a close clinical risk-benefit evaluation.

Do Indian patients with schizophrenia need half the recommended clozapine dose to achieve therapeutic serum level? An exploratory study

Inter-racial differences in serum clozapine have received less scientific importance, as there are fewer studies on therapeutic drug monitoring (TDM) from Asia. We measured the serum clozapine levels in 142 patients with schizophrenia and related disorders at a tertiary care psychiatric institute in India. The clozapine concentration per milligram (mg) of oral clozapine dose (C/D ratio) was calculated, and the C/D ratio was used to estimate oral clozapine dose needed to achieve therapeutic serum clozapine level (350 ng/ml). This study examined Indian patients only and compared the results with weighted mean serum clozapine and its correlates in Caucasian population, based on published scientific literature. The median C/D ratio in our sample was 2.5 (n = 142), and the clozapine dose needed to achieve therapeutic serum clozapine level was 140 mg/d. The median C/D ratio of our subjects was nearly two and a half times higher than the weighted mean C/D ratio of Caucasians (2.5 v/s 1.07) reported elsewhere. After excluding the significant pharmacokinetic interactions and stratifying according to gender and smoking status, the estimated clozapine dose to achieve therapeutic serum level in male smokers (n = 9) and female non-smokers (n = 38) were 238 mg/d (C/D ratio; 1.47) and 120 mg/d (C/D ratio:2.93) respectively. On comparing, male smokers (600 mg/d versus 238 mg/d) and female non-smokers (300 mg/d versus 120 mg/d) in our study needed about 40% of the recommended clozapine dose for Caucasians to achieve therapeutic serum clozapine level. The pharmacogenetic correlates of lesser clozapine dose requirement in the Indian population require further research.

Integration of Clozapine-associated Harm Obsessions into Cognitive Behavioral Conceptualization and Treatment Planning for Thought Broadcasting: A Case Study

BACKGROUND AND OBJECTIVES

As many as 30% of individuals with a schizophrenia spectrum disorder experience obsessive-compulsive symptoms (OCS). Clozapine has demonstrated superior efficacy for the treatment of medication-resistant schizophrenia but it is also associated with an increased risk for OCS. Because pharmacologic management of clozapine-related OCS can be particularly challenging, cognitive behavioral therapy (CBT) should be considered. Nevertheless, there are few detailed accounts of CBT for OCS and schizophrenia.

METHODS

The authors describe the interdisciplinary outpatient care of a client who had a 25-year history of schizoaffective disorder, bipolar type, and OCS. The case formulation was used to guide interventions to target core schemas of being dangerous and defective. The case study describes the cognitive behavioral formulation, treatment targets, treatment course, and functional and symptom response.

RESULTS

The client received 21 sessions of a formulation-based CBT for psychosis protocol, which included a 6-session course of exposure with response prevention, consisting of imaginal and in vivo exposure to multiple salient harm stimuli. Reduced ratings of distress and a 50% reduction in OCS suggest that habituation and inhibitory learning occurred. The treatment of OCS resulted in the complete resolution of thought broadcasting. Subsequently, the client was more successful in his efforts to adhere to an action schedule.

LIMITATIONS

The use of both the treatment approach described in this clinical case report and contemporaneous medication management preclude comment on the mechanism(s) of the therapeutic change observed in this case.

CONCLUSIONS

This report presents a means of conceptualizing the interplay between thought broadcasting and harm obsessions and discusses considerations in identifying and treating individuals with similar comorbid conditions, particularly in the context of clozapine treatment for medication-resistant psychosis.

Using therapeutic drug monitoring to personalize clozapine dosing in Asians

This narrative review on clozapine blood levels or therapeutic drug monitoring (TDM) includes sections focused on drug clearance and TDM, personalized dosing with TDM, clinical applications of TDM in Asians, and areas needing further study. Asian patients need half the clozapine dose (D) used in the United States to get the same blood concentrations (C). The concentration-to-dose (C/D) ratio measures drug clearance. In the United States, the average clozapine patient usually needs from 300 to 600 mg/day to reach 350 ng/mL. US male smokers reach this therapeutic C with a D of 600 mg/day (C/D ratio of 0.60 = 600/350), whereas US female nonsmokers usually need a D of 300 mg/day (C/D ratio of 1.17 = 300/350). While in the United States, average CLO C/D ratios typically are 0.6-1.2 ng/mL per mg/day, in Asian populations they range from 1.20 in male smokers to 2.40 in female smokers, requiring Ds of 300 to 150 mg/day to obtain 350 ng/mL. Asian patients can become clozapine poor metabolizers (PMs), needing very low Ds (50-150 mg/day) to get therapeutic Cs, by taking inhibitors (fluvoxamine, oral contraceptives and valproic acid), due to obesity, or during inflammations with systemic effects. In 573 Asian patients from five samples, around 1% were PMs due to taking inhibitors, 1% due to inflammation, 1% due to obesity, and 7% were potential genetic PMs. The potential genetic PMs ranged between 3% and 13%, but this prevalence will have to be better established in future studies including genetic testing for possible CYP1A2 mutations, which may explain PM status.

Exploring the Prevalence of Clozapine Phenotypic Poor Metabolizers in 4 Asian Samples: They Ranged Between 2% and 13

PURPOSE/BACKGROUND

Clozapine clearance is influenced by sex, smoking status, ethnicity, coprescription of inducers or inhibitors, obesity, and inflammation. In 126 Beijing inpatients, we measured repeated trough steady-state serum concentrations and identified 4% (5/126) who were phenotypical poor metabolizers (PMs); none were ultrarapid metabolizers (UMs). They were defined as being 2 SDs beyond the means of total clozapine concentration/dose ratios stratified by sex and smoking. Using this definition, this study explores the prevalence of PMs and UMs using data from 4 already published Asian samples. Three samples were East Asian (Beijing 2, Taipei, and Seoul); one was from South India (Vellore).

FINDINGS/RESULTS

The prevalence of phenotypical PMs ranged from 2% to 13%, but inflammation was not excluded. The prevalence was 7% (14/191) for Beijing 2, 11% (8/70) for Taipei, 13% (9/67) for Seoul, and 2% (2/101) for the Vellore sample. Five phenotypic PMs appeared to be associated with extreme obesity. Phenotypic UM prevalence ranged from 0% to 1.6% but may be partly explained by lack of adherence. A Vellore phenotypic UM appeared to be associated with induction through high coffee intake.

IMPLICATIONS/CONCLUSIONS

Approximately 10% of Asians may be clozapine PMs and may need only 50 to 150 mg/d to get therapeutic concentrations. Future studies combining gene sequencing for new alleles with repeated concentrations and careful control of confounders including inhibitors, inflammation, and obesity should provide better estimations of the prevalence of phenotypic clozapine PMs across races. Clozapine UM studies require excluding potent inducers, careful supervision of compliance in inpatient settings, and multiple serum concentrations.

Psychopharmacological Treatment of Obsessive-Compulsive Disorder (OCD)

Background:

Obsessive-compulsive disorder (OCD) is associated with affective and cognitive symptoms causing personal distress and reduced global functioning. These have considerable societal costs due to healthcare service utilization.

Objective:

Our aim was to assess the efficacy of pharmacological interventions in OCD and clinical guidelines, providing a comprehensive overview of this field.

Methods:

We searched the PubMed database for papers dealing with drug treatment of OCD, with a specific focus on clinical guidelines, treatments with antidepressants, antipsychotics, mood stabilizers, off-label medications, and pharmacogenomics.

Results:

Prolonged administration of selective serotonin reuptake inhibitors (SSRIs) is most effective. Better results can be obtained with a SSRI combined with cognitive behavioral therapy (CBT) or the similarly oriented exposure and response prevention (ERP). Refractory OCD could be treated with different strategies, including a switch to another SSRI or clomipramine, or augmentation with an atypical antipsychotic. The addition of medications other than antipsychotics or intravenous antidepressant administration needs further investigation, as the evidence is inconsistent. Pharmacogenomics and personalization of therapy could reduce treatment resistance.

Conclusions:

SSRI/clomipramine in combination with CBT/ERP is associated with the optimal response compared to each treatment alone or to other treatments. New strategies for refractory OCD are needed. The role of pharmacogenomics could become preponderant in the coming years.

Do Asian Patients Require Only Half of the Clozapine Dose Prescribed for Caucasians? A Critical Overview

Since 1997, studies have found that Asians need lower clozapine doses than Caucasians. Caucasians with average clozapine metabolism may need from 300 to 600 mg/day to reach the therapeutic range (350 ng/ml). Thus, serum clozapine concentration-to-dose (C/D) ratios typically range between 0.60 (male smokers) and 1.20 (female non-smokers). A 2019 systematic review of clozapine levels demonstrated weighted mean C/D ratios of 1.57 in 876 East Asians and 1.07 in 1147 Caucasians (P < .001). In Asian countries, average clozapine doses are lower than 300 mg/day. After sex and smoking stratification in 5 Asian samples with clozapine concentrations, the clozapine dose required to reach 350 ng/ml in female non-smokers ranged from 145 to 189 mg/day and in male smokers, from 259 to 294 mg/day. Thus, in Asian patients with average metabolism (with no inducers other than smoking, with no inhibitors, and in the absence of extreme obesity), the dose needed for clinical response may range between 150 mg/day for female non-smokers to 300 mg/day for male smokers. Clozapine levels may help personalize dosing in clozapine poor metabolizers (PMs) and ultrarapid metabolizers (UMs). Asian PMs may need very low doses (50-150 mg/day) to obtain therapeutic concentrations. About 10% (range 2-13%) of Asians are genetic PM cases. Other PMs are patients taking CYP1A2 inhibitors such as fluvoxamine, oral contraceptives, and valproate. Temporary clozapine PM status may occur during severe systemic infections/inflammations with fever and C-reactive protein (CRP) elevations. Asian UMs include patients taking potent inducers such as phenytoin, and rarely, valproate.

Obsessive-Compulsive Symptoms in Schizophrenia: an Up-To-Date Review of Literature

PURPOSE OF REVIEW

This review will aim to summarize the current body of epidemiological, clinical and therapeutic knowledge concerning specific co-occurrence of obsessive-compulsive symptoms (OCSs) and schizophrenia spectrum disorder.

RECENT FINDINGS

Almost 30% of the patients with schizophrenia display OCS, and three main contexts of emergence are identified: prodromal symptoms of schizophrenia, co-occurrence of OCS and schizophrenia and antipsychotics-induced OCS. Recent clinical studies show that patients with SZ and OCS have more severe psychotic and depressive symptoms, higher suicidality and lower social functioning. A recent cognitive investigation found that OCS and delusions share specific metacognitive profiles, particularly through a heightened need to control thoughts. Finally, a recent cross-sectional study of clozapine-induced OCS found a dose-response relationship between clozapine and OCS. OCS appeared reliably as linked to poorer outcomes among patients with schizophrenia. However, the specific clinical value of OCS among other prodromal symptoms of schizophrenia remains unknown.

Obsessive-compulsive symptoms in patients with schizophrenia: Relationships with olanzapine pharmacological parameters, psychopathology, and quality of life

Obsessive-compulsive symptoms (OCS) occur in a substantial portion of schizophrenia patients and have significant impacts on clinical course. This study was intended to investigate the relationships of OCS with pharmacological parameters of olanzapine, psychopathology, and quality of life. Totally 151 schizophrenia patients were recruited, and rated using Yale-Brown Obsessive-Compulsive scale (YBOCS), Positive and Negative Syndrome Scale (PANSS), Montgomery-Åsberg Depression Rating Scale (MADRS), and World Health Organization Questionnaire on Quality of Life: Short Form (WHOQOL-BREF). The concentrations of olanzapine and N-desmethylolanzapine were determined by HPLC. Twenty-five patients (16.6%) revealed the presence of OCS. OCS group had significantly higher olanzapine dose, more numbers of past hospitalizations, higher PANSS total, positive, negative, and general psychopathology scores, and higher MADRS score than those in non-OCS group. The WHOQOL-BREF physical subscale score in schizophrenia patients with OCS was significantly lower. Olanzapine dose, PANSS score, and MADRS score were significantly correlated with YBOCS score. Our findings highlight that OCS is highly prevalent in schizophrenia patients under olanzapine treatment, especially those at high doses. Schizophrenia patients with OCS had higher severity of psychotic and depressive symptoms and poorer quality of life. Clinicians should monitor OCS in patients with schizophrenia receiving olanzapine treatment.

Clozapine Metabolism in East Asians and Caucasians: A Pilot Exploration of the Prevalence of Poor Metabolizers and a Systematic Review

PURPOSE/BACKGROUND

In clozapine therapeutic drug monitoring (TDM) studies, Chinese reached the same concentrations using half the dosage Caucasians use. Defining clozapine poor metabolizers (PMs) requires stratification by ethnicity, smoking, and sex.

METHODS/PROCEDURES

After sex and smoking stratification in 129 Chinese inpatients (mean, 8.8 TDM samples per patient), we explored the association between the total concentration-dose (C/D) ratio and CYP1A2 (*1C, *1F, and *7) and CYP2C19 alleles (*2 and *3). A systematic literature review identified 22 clozapine TDM prior studies (13 in Caucasians and 7 in East Asians).

FINDINGS/RESULTS

In our Chinese sample, the mean total clozapine C/D ratio (ng/mL per mg/d) was 1.96 for 22 male smokers, 2.07 for 5 female smokers, 2.47 for 36 male nonsmokers, and 2.95 for 66 female nonsmokers. CYP1A2 *1C had no significant effects, and CYP1A2 *1F had small effects. Five clozapine PMs (4%) needed low clozapine doses of 75 to 115 mg/d to get therapeutic concentrations. Using the same methodology in a published Italian sample, we found 5 PMs (3.3% of 152). In the systematic review, the clozapine C/D ratio (ng/mL per mg/d) was higher when comparing: (1) weighted mean values of 1.57 in 876 East Asians versus 1.07 in 1147 Caucasians and (2) ranks of 8 East Asians versus 13 Caucasian samples (P < 0.001).

IMPLICATIONS/CONCLUSIONS

Future TDM studies need to further explore the frequency of clozapine PMs after sex and smoking stratification in East Asian and Caucasian patients. Compared with Caucasians, East Asians appear to have a clinically relevant decrease in clozapine clearance.

Distinct risk factors for obsessive and compulsive symptoms in chronic schizophrenia

BACKGROUND

Obsessive-compulsive disorder (OCD) is common in clozapine-treated patients although the actual prevalence, phenomenology and risk factors remain unclear. The aim of the present study was to address the three aforementioned questions.

METHODS

The electronic records of a large cohort of clozapine-medicated schizophrenia patients routinely screened for OCD were used. The Obsessive Compulsive Inventory Revised version (OCI-R) was available from 118 cases and a 21 points cut-off threshold for OCD was defined.

RESULTS

OCD prevalence was 47%, higher in patients on poly-pharmacy than on monotherapy (64% vs 31%; p = 0.001). Two OCI-R factors had significantly higher scores and distinct risk factors: checking behaviour (mean = 5.1; SD = 3.6) correlated with length of clozapine treatment (r = 0.21; p = 0.026), and obsessing factor (mean = 4.8; SD = 3.6) correlated with psychosis severity (r = 0.59; p = 0.001). These factors along with total OCI-R, did not correlate with either clozapine dose or plasma levels, after correcting for psychosis severity.

CONCLUSIONS

Screening for OCD in clozapine patients, and probably in those treated with structurally similar drugs with potent antiserotoninergic properties, should be widely adopted by clinicians. Further research is needed to understand the pathophysiology underlying repetitive behavior onset in clozapine-treated patients.

A case of clozapine-induced skin picking behaviour

There is some evidence consistently linking the occurrence of de novo obsessive-compulsive disorder (OCD) with clozapine. This skin-picking disorder is also known as impulsive-compulsive disorder-unspecified which with an increasing convergence with OCD has been placed in the current Diagnostic and statistical manual of mental disorders-fifth edition by American Psychiatric Association (DSM-5), in the category of the obsessive-compulsive and related disorders. To the best of our knowledge, there is no literature relating antipsychotics like clozapine with the occurrence of skin-picking behaviour. In this article, we present a case in whom skin-picking behaviour emerged during the upward dose titration of clozapine and was successfully treated with escitalopram.

Treatment of Hypochondriasis in Two Schizophrenia Patients Using Clozapine

Hypochondriasis (HYPO), an obsessive-compulsive spectrum disorder, is frequent in patients with schizophrenia (SCH) (20%), especially among those treated with clozapine (36.7%). Treatment options for OCS/OCD in patients under clozapine (CLZ) include combining clozapine with amisulpride/aripiprazole or a mood stabilizer, augmenting clozapine with a serotoninergic reuptake inhibitor, adding cognitive behavioural therapy, and gradually reducing dosage. No treatments have been proposed for HYPO in patients using clozapine so we examine these options in 2 cases and report the results. Among treatments delivered, only dosage reduction adequately worked. We recommend caution when thinking about escalating treatment and suggest trying it only when alternative interventions were not successful and weighing risk and benefits of this therapeutic strategy. Further research is needed to confirm the hypothesis that CLZ treatment induces hypochondriac symptoms, to investigate the prevalence of the phenomenon, and, mostly, to identify possible treatment strategies.

Induced Obsessive Compulsive Symptoms (OCS) in schizophrenia patients under Atypical 2 Antipsychotics (AAPs): review and hypotheses

The prevalence of OCS and OCD is higher in schizophrenic patients than in the general population. These disorders are sometimes induced by AAPs. There is higher frequency of OCS and greater severity in patients treated with antipsychotics with predominant anti-serotoninergic profiles opposed to those with predominant dopaminergic blockade. Induced OCS may be due to complex neuromodulation involving many serotonin, dopamine and glutamate receptors and several subtypes. Concerning connectivity, AAPs differentially influence the BOLD signal, depending on the intensity of D2 receptor blockade. The OFC could play a significant role, on account of its involvement in inhibitory control. There is a paradox: AAPs are efficient as augmentation to SSRI in treatment resistant OCD, some of them such as risperidone or aripiprazole have favourable effects in schizoptypic OCD, but AAPs cause induced OCS in schizophrenic patients. When prescribing AAPs, we should inform patients about this potential side effect and assess systematically OCS with Y-BOCS assessment after 1 month of treatment. Afterwards there are different strategies: Aripiprazole in combination can reduce OCS induced by clozapine, SSRI are slightly effective and CBT shows a few encouraging results. OCS are sometimes dose-dependent, so we also recommend prescribing the minimum effective dose and gradual introduction.

The schizo-obsessive disorder: a case report

Purpose: A case of schizophrenia with coexisting obsessive-compulsive symptoms is reported.

Case: The frequency of obsessive-compulsive disorder (OCD) and obsessive-compulsive symptoms (OCS) occurrence among patients suffering from schizophrenia is considerably higher in comparison to general population. The results of some studies show that schizo-obsessive disorder is characterized by higher intensity of negative and depressive symptoms. Patients with comorbid schizophrenia and obsessive-compulsive disorder show greater level of social dysfunction and they exhibit suicidal behaviours more often than patients diagnosed with schizophrenia. We present a 33-year-old female with obsessive-compulsive symptoms with onset in her early teens with no satisfactory response to treatment, in spite of her good intellect and insight into illness and cooperation.

Comment: There is some evidence suggesting that patients with “schizo-obsessive disorder” have a worse prognosis compared to the group of patients suffering only from schizophrenia, but the effect of OCD on schizophrenia symptom profile is unclear.

Psychosis or Obsessions? Clozapine Associated with Worsening Obsessive-Compulsive Symptoms

One underrecognized adverse event of clozapine is the emergence or worsening of obsessive-compulsive symptoms (OCS). OCS, particularly violent thoughts, can be inaccurately described as psychosis and result in a misdiagnosis. We report a case of a 42-year-old man, initially diagnosed with schizoaffective, who was placed on clozapine for the management of “violent delusions.” However, clozapine led to a worsening of these violent thoughts resulting in suicidal ideation and hospitalization. After exploration of the intrusive thoughts and noting these to be egodystonic, clearly disturbing, and time consuming, an alternative diagnosis of obsessive-compulsive disorder (OCD) was made. Clozapine was inevitably discontinued resulting in a significant reduction of the intrusive thoughts without emergence of psychosis or adverse events. While an overlapping phenomenology between OCD and psychotic disorders has been described, clozapine and other antiserotonergic antipsychotics have been implicated with the emergence or worsening of OCS. Unique to our case is that the patient's obsessions had been treated as psychosis leading to the inadequate treatment of his primary illness, OCD. This case highlights the potential for OCD to masquerade as a psychotic disorder and reminds clinicians that clozapine may worsen OCS.

The clinical potentials of adjunctive fluvoxamine to clozapine treatment: a systematic review

RATIONALE

New clozapine optimization strategies are warranted, as some patients do not achieve sufficient response and experience various adverse effects. Fluvoxamine is a potent CYP1A2 inhibitor and may increase the ratio of clozapine to its primary metabolite N-desmethylclozapine (NDMC).

OBJECTIVES

This study aims to review all pharmacodynamic effects and the adverse effect profile of changing the clozapine/NDMC ratio with adjunctive fluvoxamine.

METHODS

MEDLINE, Embase, and the Cochrane Library were searched with the search terms "clozapine" and "fluvoxamine" without any time limit. Language was restricted to English, Scandinavian, Polish, and German. Studies were sorted for relevance based on title and abstract. Clinical recommendations of potential indications/effects were graded as level A, B, C, or D depending on studies of high, moderate, low, or very low quality, respectively.

RESULTS

Based on data from 24 case reports/series, seven cohort studies, and two randomized controlled trials, 241 patients were studied. Evidence (A) supported that adjunctive fluvoxamine increased clozapine plasma levels. This may increase the probability of response in patients, where sufficient clozapine plasma levels cannot be achieved. Adjunctive fluvoxamine reduced metabolic adverse effects of clozapine (B) but not agranulocytosis risk (B). Although depressive or obsessive-compulsive symptoms may improve, a SSRI with no CYP1A2 inhibition should rather be used (C). No studies investigated the effect of adjunctive fluvoxamine to minimize clozapine rebound psychosis (D) or to reduce the effects of smoking on clozapine plasma levels (D).

CONCLUSIONS

Adjunctive fluvoxamine may have clinical potentials for optimizing clozapine treatment but further clinical studies are warranted to explore the clinical implications.

Behavioral and emotional adverse events of drugs frequently used in the treatment of bipolar disorders: clinical and theoretical implications

BACKGROUND

Behavioral and emotional adverse events induced by drugs commonly prescribed to patients with bipolar disorders are of paramount importance to clinical practice and research. However, no reviews on the topic have been published so far.

METHODS

An extensive search was performed. Reports were reviewed if they described behavioral side effects related to pharmacological treatments for bipolar disorders in healthy subjects or patients with different neuropsychiatric disorders. For this review, lithium, antipsychotics, anticonvulsants and selective serotonin reuptake inhibitors were included.

RESULTS

Apathy or emotional blunting, diminished sexual desire, and inability to cry were reported to be associated with exposure to selective serotonin reuptake inhibitors. Neuroleptic-induced deficit syndrome/emotional detachment and obsessive-compulsive symptomatology and decision-making modifications. A lithium-related amotivational syndrome was also reported in the literature. Furthermore, hypersexuality and obsessive-compulsive symptoms have been noted in subjects treated with lamotrigine.

LIMITATIONS

Primary studies on drug-related adverse events are scant so far and most of the data currently available derive from case reports. Moreover, most of the evidence reviewed is based on studies performed on healthy subjects and patients with neuropsychiatric conditions other than bipolar disorders.

DISCUSSION

There is a remarkable dearth of data on behavioral adverse events of pharmacological treatment for bipolar disorders. However, the pieces of evidence available at present, though scant and scattered, suggest that different behavioral adverse events may be related to pharmacological treatment for these disorders. The implications of these findings for research and management of patients with mood disorders are discussed.

Suicidality in clozapine-treated patients with schizophrenia: role of obsessive-compulsive symptoms

Patients with schizophrenia have an increased lifetime risk of comorbid obsessive-compulsive symptoms. Up to 30% of these patients experience such symptoms and 12% may be diagnosed with obsessive-compulsive disorder. The presence of these symptoms in schizophrenia seems to be associated with poor outcomes including a greater suicidal risk. A subgroup of patients develops this symptomatology after the initiation with Second Generation Antipsychotics (SGA). Also, there is evidence of a causal relationship for this association, particularly for clozapine. The primary aim of this study was to investigate the association of this comorbidity with suicidality in a population of clozapine-medicated schizophrenic and schizoaffective patients (N=65). The prevalence of obsessive-compulsive symptoms in our sample was 29.2% (N=19) and the prevalence of obsessive-compulsive disorder was 13.8% (N=9). Significant positive correlations between suicidality and total Y-BOCS score and between Y- BOCS score and depressive symptoms were found. Further analysis indicated that a Y-BOCS score greater or equal than 8 was an independent predictor of suicide attempt during clozapine treatment. Routine screening for this adverse event should be warranted for this population.

Relationship of obsessive compulsive symptoms/disorder with clozapine: A retrospective study from a multispeciality tertiary care centre

OBJECTIVE

To study the prevalence, phenomenology and course of OCS/OCD in patients receiving clozapine.

METHODOLOGY

Case records of 220 patients who received clozapine for at least 3 months were reviewed.

RESULTS

One fifth (N=42; 19.1%) of patients had OCS/OCD, of which majority (13.2%) had onset of OCS/OCD prior to starting of clozapine and remaining 5.9% developed OCS/OCD after starting of clozapine. About one fourth of the patients with pre-existing OCS/OCD had worsening with clozapine while the remaining maintained at the same level (55.17%) or improved (20.7%). Majority of the patients who developed de novo OCS/OCD on clozapine were females and OCS/OCD emerged within 12 months (69.2%) of starting of clozapine. In those who developed OCS/OCD with clozapine, among obsessions, pathological doubts were most common, followed by obsessions with sexual content; among compulsions repetitive checking was the most common. SSRIs were required for management in half the patients, while the remaining improved spontaneously or with reduction in clozapine dose.

CONCLUSION

Clozapine can lead to aggravation or de novo presentation of OCS/OCD but these can be managed with reduction in dose or addition of SSRIs.

Factors associated with subjective side-effects during clozapine treatment

OBJECTIVE

Clozapine is associated with subjectively unpleasant or clinically serious side-effects, which may affect treatment adherence. The aims of the study were to explore the association of clozapine+ norclozapine serum concentration and other factors with subjective side-effects in schizophrenia patients.

METHODS

In this cross-sectional study, 237 patients with a diagnosis of schizophrenia, schizo-affective or other non-organic psychoses completed the Liverpool University Neuroleptic Side Effect Rating Scale (LUNSERS), a self-report scale measuring side-effects of antipsychotics and a clinical questionnaire. Clozapine+ norclozapine serum concentration of 190 patients was measured. Of the patients 80 (33.7%) were on antipsychotic combination therapy.

RESULTS

Higher clozapine+ norclozapine concentrations were associated with the depression-anxiety factor of LUNSERS and antipsychotic combination treatments were associated with sympatichotonia-tension factor. Younger patients reported sedation more often than older patients.

CONCLUSION

According to the present results, high clozapine concentrations were associated with depression-anxiety symptoms, but the causality remains unknown.

Neuropsychological profile and treatment-related features among patients with comorbidity between schizophrenia spectrum disorder and obsessive–compulsive disorder: is there evidence for a “schizo-obsessive” subtype?

Epidemiological studies have found that obsessive–compulsive disorder (OCD) is estimated to occur in 12% of patients with schizophrenia. Whether this “schizo-obsessive” subgroup may be posited as a clinical entity with a distinct neuropsychological profile and treatment-related features remains unclear. A sample of 30 patients who met DSM-IV criteria for both schizophrenia/schizoaffective disorder and OCD was compared with 30 OCD subjects and with 37 patients with schizophrenia/schizoaffective disorder. Neuropsychological domains were measured by the Wechsler Adult Intelligence Scale - Third Edition (WAIS-III), the Trail Making Test (TMT), and the verbal fluency test (FAS). Treatment-related variables were assessed with the Clinical Global Improvement scale (CGI), the Drug Attitude Inventory (DAI), and dosage/type of antipsychotic medications. One-way analysis of variance revealed statistically significant differences among the three groups in “working memory,” “block design,” “semantic fluency,” TMT-A, and TMT-B. However, the Bonferroni correction showed no statistical differences between both psychotic groups. In addition, there were no significant differences among the three groups in the CGI and DAI, although “schizo-obsessive” patients tended to display slightly higher scores on these variables than the other groups. Overall, these findings do not support the hypothesis that comorbidity between schizophrenia spectrum disorders and OCD may reflect a distinct clinical entity. However, further research with larger sample sizes and a more comprehensive clinical assessment are needed. Our findings also underscore the fact that divergences among assessment instruments, as well as confounding variables, may influence results on neuropsychological domains.

Second generation antipsychotic-induced obsessive-compulsive symptoms in schizophrenia: a review of the experimental literature

Second generation antipsychotics (SGAs) have been implicated in the de novo emergence and exacerbation of obsessive-compulsive symptoms (OCS) in patients with schizophrenia. Among SGAs, clozapine, olanzapine, and risperidone are the most prominent agents associated with these sequelae, according to case reports. Comorbid OCS can impede recovery by compromising treatment benefits, medication compliance, and clinical prognoses. Previous reviews of SGA-induced OCS have predominantly focused on descriptive case reports, with limited attention paid toward experimental findings. To address this paucity of data, we sought to review the effects of SGAs on OCS in schizophrenia in the experimental literature, while addressing the role of different treatment (duration, dose, serum levels) and pharmacogenetic factors. Our findings suggest that clozapine confers the greatest risk of OCS in schizophrenia, with 20 to 28% of clozapine-treated patients experiencing de novo OCS, in addition to 10 to 18% incurring an exacerbation of pre-existing OCS. Clozapine can also yield full threshold obsessive-compulsive disorder (OCD), in some cases. Olanzapine is another high risk drug for secondary OCS which occurs in 11 to 20% of schizophrenic patients receiving olanzapine therapy. At this time, there is insufficient experimental evidence to characterize the effects of other SGAs on OCS. Despite some experimental support for the involvement of longer treatment duration and genetic factors in mediating drug-induced OCS, more research is needed to clearly elucidate these associations. Based on these results, schizophrenic patients should be routinely monitored for OCS throughout the course of SGA treatment, particularly when clozapine or olanzapine is administered.

Psychopathology and quality of life among patients with comorbidity between schizophrenia spectrum disorder and obsessive-compulsive disorder: no evidence for a "schizo-obsessive" subtype

BACKGROUND

Epidemiological studies have found that obsessive-compulsive disorder (OCD) is estimated to occur in up to 12% of patients with schizophrenia. Furthermore, several etiopathogenic mechanisms have been postulated for understanding this co-occurrence. Whether this subgroup of "schizo-obsessive" patients may be posed as a clinical entity with a distinct psychopathological and functioning profile remains unclear.

METHOD

A sample of adult patients who met DSM-IV criteria for both schizophrenia/schizoaffective disorder and OCD (n=30) was compared with a "non-OCD schizophrenic" group (n=37) and another subset of "non-schizophrenic OCD" patients (n=30). The Positive and Negative Syndrome Scale (PANSS), the Scale to Assess Unawareness of Mental Disorder (SUMD), the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Brown Assessment of Beliefs Scale (BABS), the Clinical Global Severity scale (CGI), the Quality of Life Scale (QLS), and the Beck's Depression Inventory (BDI) were used.

RESULTS

We found that "schizo-obsessive" subjects did not show significant differences in any outcome measures when compared to the "non-OCD schizophrenic" group. Furthermore, statistical analyses also revealed that the "non-schizophrenic OCD" group tended to have lower severity of psychopathology as well as greater quality of life than both psychotic groups.

CONCLUSIONS

These findings indicate that comorbidity between schizophrenia/schizoaffective disorder and OCD does not comprise a distinct clinical entity, particularly when compared to "non-OCD schizophrenia" disorder. Discrepancies among previous studies may be justified by methodological divergences.

Comorbid Obsessive-Compulsive Symptoms in Schizophrenia: Insight into Pathomechanisms Facilitates Treatment

Insight into the biological pathomechanism of a clinical syndrome facilitates the development of effective interventions. This paper applies this perspective to the important clinical problem of obsessive-compulsive symptoms (OCS) occurring during the lifetime diagnosis of schizophrenia. Up to 25% of schizophrenia patients suffer from OCS and about 12% fulfil the diagnostic criteria of obsessive-compulsive disorder (OCD). This is accompanied by marked subjective burden of disease, high levels of anxiety, depression and suicidality, increased neurocognitive impairment, less favourable levels of social and vocational functioning, and greater service utilization. Comorbid patients can be assigned to heterogeneous subgroups. It is assumed that second generation antipsychotics (SGAs), most importantly clozapine, might aggravate or even induce second-onset OCS. Several epidemiological and pharmacological arguments support this assumption. Specific genetic risk factors seem to dispose patients with schizophrenia to develop OCS and risk-conferring polymorphisms has been defined in SLC1A1, BDNF, DLGAP3, and GRIN2B and in interactions between these individual genes. Further research is needed with detailed characterization of large samples. In particular interactions between genetic risk constellations, pharmacological and psychosocial factors should be analysed. Results will further define homogeneous subgroups, which are in need for differential causative interventions. In clinical practise, schizophrenia patients should be carefully monitored for OCS, starting with at-risk mental states of psychosis and longitudinal follow-ups, hopefully leading to the development of multimodal therapeutic interventions.

Pharmacogenetics of membrane transporters: a review of current approaches

This chapter provides a review of the pharmacogenetics of membrane transporters, including ABC transporters and OATPs. Membrane transporters are heavily involved in drug disposition, by actively transporting substrate drugs between organs and tissues. As such, polymorphisms in the genes encoding these proteins may have a significant effect on the absorption, distribution, metabolism, excretion, and activity of compounds. Although few drug transporter polymorphisms have transitioned from the bench to the bedside, this chapter discusses clinical development of transporter pharmacogenetic markers. Finally, development of SLCO1B1 genotyping to avoid statin induced adverse drug reactions is discussed as a model case for transporter pharmacogenetics clinical development.

Aripirazole augmentation in clozapine-associated obsessive-compulsive symptoms in schizophrenia

OBJECTIVE

Patients with schizophrenia often experience comorbid obsessive-compulsive symptoms. Within these patients, a significant subgroup developed secondary obsessive-compulsive symptoms during treatment with clozapine.

METHOD

In this paper, we report on four cases in which adjunctive therapy with aripiprazole was tested to alleviate obsessive-compulsive symptoms in schizophrenia.

RESULTS

All four patients had a significant improvement in obsessive-compulsive symptoms. The combination of clozapine and aripiprazole was well tolerated.

CONCLUSION

This case series demonstrates the clinical efficacy of aripiprazole adjunctive therapy with clozapine in schizophrenic patients with comorbid obsessive-compulsive symptoms. Larger-sampled and controlled studies are required in order to test and confirm these observations.

Comorbid obsessive-compulsive symptoms in schizophrenia: contributions of pharmacological and genetic factors

A large subgroup of around 25% of schizophrenia patients suffers from obsessive-compulsive symptoms (OCS) and about 12% fulfill the diagnostic criteria of an obsessive-compulsive disorder (OCD). The additional occurrence of OCS is associated with high subjective burden of disease, additional neurocognitive impairment, poorer social and vocational functioning, greater service utilization and high levels of anxiety and depression. Comorbid patients can be assigned to heterogeneous subgroups. One hypothesis assumes that second generation antipsychotics (SGAs), most importantly clozapine, might aggravate or even induce second-onset OCS. Several arguments support this assumption, most importantly the observed chronological order of first psychotic manifestation, start of treatment with clozapine and onset of OCS. In addition, correlations between OCS-severity and dose and serum levels and duration of clozapine treatment hint toward a dose-dependent side effect. It has been hypothesized that genetic risk-factors dispose patients with schizophrenia to develop OCS. One study in a South Korean sample reported associations with polymorphisms in the gene SLC1A1 (solute carrier family 1A1) and SGA-induced OCS. However, this finding could not be replicated in European patients. Preliminary results also suggest an involvement of polymorphisms in the BDNF gene (brain-derived neurotrophic factor) and an interaction between markers of SLC1A1 and the gene DLGAP3 (disc large associated protein 3) as well as GRIN2B (N-methyl-D-aspartate receptor subunit 2B). Further research of well-defined samples, in particular studies investigating possible interactions of genetic risk-constellations and pharmacodynamic properties, are needed to clarify the assumed development of SGA-induced OCS. Results might improve pathogenic concepts and facilitate the definition of at risk populations, early detection and monitoring of OCS as well as multimodal therapeutic interventions.

Polymorphisms in the glutamate transporter gene SLC1A1 and obsessive-compulsive symptoms induced by second-generation antipsychotic agents

BACKGROUND

A large subgroup of schizophrenic patients develops obsessive-compulsive symptoms (OCS) during treatment with second-generation antipsychotics (SGA). A genetic risk factor for these secondary OCS was recently described in the gene SLC1A1 encoding the neuronal glutamate transporter excitatory amino acid carrier 1. The aim of this study was to replicate these findings in a European sample.

METHODS

A total of 103 schizophrenic patients treated with SGAs were included. Three single nucleotide polymorphisms in SLC1A1 (rs2228622, rs3780412 and rs3780413), which had been associated with SGA-induced OCS, were investigated. Single marker and haplotype analyses were tested with logistic regressions using age, sex and medication type as covariates.

RESULTS

Treatment with markedly antiserotonergic SGAs such as clozapine was more prevalent in the subgroup of patients with comorbid OCS (P<0.001). The dosage and duration of clozapine treatment correlated significantly with the severity of OCS. In contrast to the Asian sample, no genetic associations were found with OCS.

CONCLUSION

Larger samples are necessary to unravel the interplay of pharmacological and genetic risk factors for OCS in schizophrenia.

Differential effects of antipsychotic agents on obsessive-compulsive symptoms in schizophrenia: a longitudinal study

Indirect evidence supports the assumption that antiserotonergic second-generation antipsychotics (SGA) induce and aggravate obsessive-compulsive symptoms (OCS) in schizophrenia. However, multimodal studies assessing the long-term interaction of pharmacotherapy and psychopathology are missing. Over 12 months, we followed-up 75 schizophrenia patients who were classified into two groups according to antipsychotic treatment: clozapine or olanzapine (group I) versus aripiprazole or amisulpride (group II). We applied the Yale Brown Obsessive Compulsive Scale (YBOCS) and investigated between-group changes over time as the primary endpoint. Group I showed markedly higher YBOCS scores at both time points. Repeated measure analyses of variance (ANOVAs) revealed significant interaction effects of group and time (per protocol sample (PP): p=0.006). This was due to persistently high OCS severity within group I, and decreasing YBOCS scores within group II. OCS severity correlated significantly with the negative and general psychopathology subscales of the Positive and Negative Syndrome Scale (PANSS), as well as with depressive symptoms. The progressive differences in OCS severity between our groups support the assumption of differential pharmacodynamic effects on comorbid OCS in schizophrenia. Further studies should address the pathogenetic mechanism, define patients at risk and facilitate early detection as well as therapeutic interventions.

Clozapine-induced obsessive-compulsive symptoms in schizophrenia: a critical review

Obsessive-compulsive disorder (OCD) is rarely associated with schizophrenia, whereas 20 to 30% of schizophrenic patients, suffer from comorbid obsessive-compulsive symptoms (OCS). So far no single pathogenetic theory convincingly explained this fact suggesting heterogeneous subgroups. Based on long-term case observations, one hypothesis assumes that second-onset OCS in the course of schizophrenia might be a side effect of second generation antipsychotics (SGA), most importantly clozapine (CLZ). This review summarizes the supporting epidemiological and pharmacological evidence: Estimations on prevalence of OCS increase in more recent cross-sectional studies and in later disease stages. Longitudinal observations report the de novo-onset of OCS under clozapine treatment. This association has not been reported with first generation antipsychotics (FGA) or SGAs with mainly dopaminergic mode of action. Finally, significant correlations of OCS-severity with duration of treatment, dose and serum levels suggest clozapine-induced OCS. However, supposed causal interactions need further verifications. It is also unclear, which neurobiological mechanisms might underlie the pathogenetic process. Detailed genotypic and phenotypic characterizations of schizophrenics with comorbid OCS regarding neurocognitive functioning and activation in sensitive tasks of functional magnetic imaging are needed. Multimodal large-scaled prospective studies are necessary to define patients at risk for second-onset OCS and to improve early detection and therapeutic interventions.

Clozapine for the treatment of schizophrenia

INTRODUCTION

Despite considerable progress in the pharmacological treatment of schizophrenia, about 30% of patients are minimally responsive to antipsychotics and there is still an excessively high rate of mortality in schizophrenia patients. Clozapine , a D(2)-5HT(2) antagonist, was the first antipsychotic to demonstrate efficacy in treatment-resistant patients, and to be associated with the lowest risk of death.

AREAS COVERED

The pharmacodynamics, pharmacokinetics, clinical efficacy, safety and cost-effectiveness of clozapine are covered in this article, based on a literature review (PubMed) from 1975 to 2012. Pivotal, as well as supporting, randomized controlled trials are reviewed, along with observational and/or naturalistic safety studies. This review of clozapine will allow the reader to determine the place for clozapine in the schizophrenia treatment landscape.

EXPERT OPINION

Studies conducted so far suggest that clozapine is the treatment of choice for schizophrenic patients who are refractory to treatment, display violent behaviors, or who are at high risk of suicide. However, it is also the antipsychotic with the worst side effect profile, the highest risk of complications, and the most difficult to prescribe. Experience with clozapine should therefore be included in the education of future physicians.

Does clozapine cause or worsen obsessive compulsive symptoms? An analysis and literature review

BACKGROUND

Clozapine is the most effective antipsychotic in treatment-resistant schizophrenia but its use portends with a high burden of adverse reactions. One adverse event reported both in case reports and cross-sectional surveys is the emergence or worsening of obsessive compulsive symptoms (OCS).

OBJECTIVES

This study presents a retrospective review of a UK cohort of clozapine-treated individuals with the aim to further investigate the complex relationship between clozapine and OCS.

METHODS

An extensive review of the medical records of 49 patients receiving clozapine in the Southampton area was undertaken. We searched for a diagnosis of obsessive compulsive disorder, signs or symptoms of obsessive compulsive disorder or the prescribing of selected antidepressants the year before clozapine initiation and the year after.

RESULTS

Fifteen patients (31%) had reports of OCS during the 2-year data collection period. Twelve patients (24%) had OCS before clozapine initiation while only 7 (14%) had symptoms after clozapine was initiated. De novo OCS were reported in three (6%) cases after 5-9 months of clozapine treatment.

CONCLUSIONS

As with previous studies it was not possible to establish a definitive link between clozapine and OCS. Clinicians should be mindful of the common comorbidity of OCS and schizophrenia and the possible increased risk incurred when starting clozapine.

Antiserotonergic antipsychotics are associated with obsessive-compulsive symptoms in schizophrenia

BACKGROUND

Epidemiological investigations show that up to 30% of schizophrenic patients suffer from obsessive-compulsive symptoms (OCS) associated with negative impact on the general prognosis. It has been proposed that antiserotonergic second-generation antipsychotics (SGAs) might induce OCS, but investigations of large samples integrating psychopathology, neuropsychology and psychopharmacology are missing.

METHOD

We stratified 70 patients with schizophrenia according to their mode of antipsychotic treatment: clozapine and olanzapine (group I) compared with aripiprazole and amisulpride (group II). The groups were matched according to age, sex, educational levels and severity of the psychotic disorder (Positive and Negative Syndrome Scale). As the primary endpoint, we evaluated OCS severity (Yale-Brown Obsessive-Compulsive Scale).

RESULTS

OCS were significantly more prevalent and severe in group I, in which OCS severity correlated with dosage of clozapine and duration of treatment. Pronounced cognitive deficits in group I were found in visuospatial perception and visual memory (Wechsler Adult Intelligence Scale-Revised block design, Rey-Osterrieth Complex Figure Test), impulse inhibition (go/no-go test), higher perseveration scores (Wisconsin Card Sorting Test) and reduced set-shift abilities (Trail Making Test Part B, Set-shift Task). These cognitive domains correlated with OCS severity.

CONCLUSIONS

OCS in schizophrenia are associated with antiserotonergic SGA treatment, but longitudinal studies have to prove causality. Before starting treatment with antiserotonergic SGAs, specific neurocognitive domains should be evaluated, as visuospatial learning and impulse inhibition performance might allow early detection of OCS secondary to antipsychotic treatment in schizophrenia.