Clozapine impact on clinical outcomes and aggression in severely ill adolescents with childhood-onset schizophrenia

Clozapine Treatment for Aggressive Behaviors in Youths with Neurodevelopmental Disorders

Objectives: The aim of this study was to assess effectiveness and tolerability of Clozapine in the treatment of aggression in youth with Neurodevelopmental Disorders. Methods: Patients were consecutively admitted at our third-level university hospital with nationwide catchment from June 2018 to October 2022, and followed up to July 2023. Eligibility criteria were as follows: (1) Autism Spectrum Disorder (ASD) and/or Intellectual Disability/Borderline Cognitive Functioning, (2) behavioral dyscontrol with physical aggression; (3) age range between 8 and 18 years; (4) clinical indication for Clozapine treatment after at least two failed trials with other Second-Generation Antipsychotics (SGAs); (5) availability of an at least 6-month-long follow-up. To evaluate the response to Clozapine, we used the Clinical Global Impressions (CGI) rating scales (Clinical Global Impressions-Severity [CGI-S] and Clinical Global Impressions-Improvement [CGI-I]), the Children's Global Assessment Scale (CGAS), and the Aberrant Behavior Checklist (ABC). Results: Twenty-six children and adolescents (21 boys, age 13.47 ± 2.05 years, follow-up duration 9.77 ± 3.50 months) were included in the analysis. Clinical severity (CGI-S) and functional impairment (Clinical Global Assessment Scale) significantly improved, as well as the ABC Total Score and the scores in several subscales. Sixteen patients (61.54%) were responders (CGI-I ≤2), and 13 (50.00%) displayed remission of aberrant behaviors (ΔABC-Total >35), while response/remission condition was not affected by add-on medications and psychotherapy. Most frequent side effects were increased appetite (50.00%), sialorrhea (38.46%), and increased repetitive behaviors (26.92%). Two patients presented epileptic seizures, while no patients presented leucopoenia. Conclusions: Our results suggest that Clozapine may be helpful in ameliorating treatment-resistant aggression in youth with neurodevelopmental conditions. Possible pharmacological strategies for the management of most frequent side effects are also suggested.

A systematic review of clozapine for aggression and violence in patients with schizophrenia or schizoaffective disorder

Although uncommon, the risk of aggression and violence is greater in people with schizophrenia than in the general population. Clozapine is the "gold standard" pharmacologic treatment for the management of persistent agitation and aggression in people with schizophrenia and is consistently recommended by guidelines and reviews for this purpose. Although clozapine is indicated for treatment-resistant schizophrenia based on its superior efficacy, studies have proposed that clozapine may have specific properties that ameliorate aggression and hostility that are distinct from its antipsychotic effects. A literature review was conducted on June 3, 2023, using the US National Library of Medicine's PubMed resource to identify articles focusing on clozapine for the treatment of aggression, violence, and/or hostility in patients with schizophrenia or schizoaffective disorder. The majority of evidence, including from randomized control trials, supports the utilization of clozapine as maintenance treatment for persistent aggressive behavior in patients with schizophrenia, and supports that its anti-aggressive effects may be independent from its antipsychotic properties (e.g. - treatment of hallucinations and delusions). Future randomized control studies evaluating clozapine and clozapine serum levels with aggression as the primary outcome would be of benefit.

Clozapine for Management of Childhood and Adolescent-Onset Schizophrenia: A Systematic Review and Meta-Analysis

Background: Schizophrenia at a young age deserves investigation because of the greater severity and burden of illness on individuals and health care than its adult onset. For this study, we included both childhood-onset schizophrenia and early-onset schizophrenia. We used the common term "childhood and adolescent-onset schizophrenia (CAOS)" for either type. This systematic review provides an overview of the clinical use, efficacy, and safety of clozapine treatment in managing CAOS. Methods: We conducted a systematic literature search in PubMed, Embase, and PsycINFO databases. We searched for randomized controlled trials (RCTs), open-label studies (OLSs), review articles, meta-analytic and observational studies. Our literature search resulted in 1242 search results. After the title, abstract, and full article review, 18 studies qualified (double-blind RCTs n = 4; OLS n = 4; observational studies n = 7; case reports n = 3). Results: Clozapine use in CAOS was generally well tolerated and not associated with any fatalities. Clozapine use in the short term (6 weeks) and long term (2-9 years) was superior in efficacy than other antipsychotics in CAOS management. Improvement in overall symptoms was maintained during long-term follow-up over the years in OLSs. Clozapine appeared to have a favorable clinical response and shorter hospital stays. Sedation and hypersalivation were commonly reported (90%), constipation was next in frequency (13%-50%). Neutropenia was seen in 6%-15% of cases and agranulocytosis (<0.1%). Although weight gain was common (up to 64%), followed by metabolic changes (8%-22%), treatment-onset diabetes was less frequent (<6%). Akathisia, tachycardia, and blood pressure changes were less commonly seen. Conclusions: Limited studies indicate that clozapine is a safe and efficacious option for CAOS management. We need large-scale and well-designed long-term RCTs for the use of clozapine in the management of CAOS.

Interest of Fluvoxamine as an Add-On to Clozapine in Children With Severe Psychiatric Disorder According to CYP Polymorphisms: Experience From a Case Series

Despite its drastic efficacy in resistant psychiatric disorders, clozapine remains rarely used in youth due to its side effects. Clozapine plasma level is determined through its metabolism involving several isoforms of cytochromes 450 (CYP450) family. Isoform CYP1A2 appears as a limiting enzyme involved in the metabolism of clozapine, while isoforms 2C19, 2D6, 3A4, and 3A5 also contribute in a minor way. Clozapine efficacy is limited by a significant inter-patient variability in exposure according to CYP's polymorphisms. Clozapine plasma levels may be increased with CYP inhibitors such as fluvoxamine. This drug is a potent enzymatic inhibitor of CYP1A2 and, to a lesser extent, of CYP3A4 and CYP2D6. Hence, in case of CYP's polymorphisms in youth, the use of fluvoxamine as add-on to clozapine could help in reaching clinical and biological efficacy and allowing lower clozapine dosage and a better tolerance profile as it has already been described in adults. We report four pediatric cases with severe psychiatric disorders underlying our experience with CYP polymorphism explorations and the use of fluvoxamine as add-on to clozapine. Our four patients clinically improved after the introduction of fluvoxamine, enhancing clozapine metabolism and therefore the clozapine plasma level within therapeutic range. Despite the interesting results of fluvoxamine, we report a severe issue of tolerance for one patient, emphasizing the need for caution regarding possible drug interactions when fluvoxamine is considered. Hence, we propose a detailed step-by-step multidisciplinary protocol.

Pharmacological treatment of violence in schizophrenia

Chronic aggression and violence in schizophrenia are rare, but receive disproportionate negative media coverage. This contributes to the stigma of mental illness and reduces accessibility to mental health services. Substance Use Disorders (SUD), antisocial behavior, non-adherence and recidivism are known risk factors for violence. Treatment with antipsychotic medication can reduce violence. Aside from clozapine, long-acting injectable antipsychotics (LAI) appear to be superior to oral antipsychotics for preventing violence, addressing adherence and recidivism. LAI also facilitate the implementation of functional skills training. For the high-risk recidivist target population with schizophrenia, better life skills have the potential to also reduce the risk for contact with the legal system, including an improved ability to live independently in supported environments and interact appropriately with others. High-risk patients who are resistant to treatment with other antipsychotics should receive treatment with clozapine due to its direct positive effects on impulsive violence, along with a reduction in comorbid risk factors such as SUDs.

Clozapine response trajectories and predictors of non-response in treatment-resistant schizophrenia: a chart review study

Although clozapine is the main antipsychotic medication for treatment-resistant schizophrenia, 40-70% of patients on clozapine have persistent psychotic symptoms (i.e. ultra-treatment-resistant schizophrenia, UTRS). We aimed to examine clozapine response/non-response patterns in patients with treatment-resistant schizophrenia, as well as determine patient clinico-demographic factors associated with long-term clozapine non-response. Clinico-demographic characteristics of 241 patients on clozapine were collected through a retrospective chart review. The median (interquartile range, IQR) follow-up from illness onset was 25.0 (IQR = 24.0) years. Clozapine response was assessed at median 10.8 (IQR = 14.0) months (Time 1, T1) and 7.2 (IQR = 13.5) years (Time 2, T2) after its initiation. It was evaluated by chart reviewers based on the information provided in clinical notes. Binomial logistic regression was used to determine clinico-demographic factors associated with clozapine non-response at both T1 and T2 (i.e. stable UTRS, S-UTRS) compared to clozapine response at both times (i.e. stable clozapine responders, S-ClozResp). Among clozapine responders (n = 122) at T1, 83.6% remained clozapine responsive and 16.4% became non-responsive at T2. In the UTRS group (n = 119) at T1, 87.4% remained clozapine non-responsive and 12.6% became responsive at T2. Duration of delay in clozapine initiation (OR = 0.94, Wald χ² = 5.33, p = 0.021) and number of pre-clozapine hospitalizations (OR = 0.95, Wald χ² = 5.20, p = 0.023) were associated with S-UTRS. Most UTRS patients were non-responsive to clozapine from the start of treatment. Preventing delay in initiating clozapine and relapses could help promote long-term clozapine response in patients with treatment-resistant schizophrenia. Future longitudinal studies are required to explore the neuropathological correlates of relapses and delay in clozapine initiation.

Immediate Early Genes Anchor a Biological Pathway of Proteins Required for Memory Formation, Long-Term Depression and Risk for Schizophrenia

While the causes of myriad medical and infectious illnesses have been identified, the etiologies of neuropsychiatric illnesses remain elusive. This is due to two major obstacles. First, the risk for neuropsychiatric disorders, such as schizophrenia, is determined by both genetic and environmental factors. Second, numerous genes influence susceptibility for these illnesses. Genome-wide association studies have identified at least 108 genomic loci for schizophrenia, and more are expected to be published shortly. In addition, numerous biological processes contribute to the neuropathology underlying schizophrenia. These include immune dysfunction, synaptic and myelination deficits, vascular abnormalities, growth factor disruption, and N-methyl-D-aspartate receptor (NMDAR) hypofunction. However, the field of psychiatric genetics lacks a unifying model to explain how environment may interact with numerous genes to influence these various biological processes and cause schizophrenia. Here we describe a biological cascade of proteins that are activated in response to environmental stimuli such as stress, a schizophrenia risk factor. The central proteins in this pathway are critical mediators of memory formation and a particular form of hippocampal synaptic plasticity, long-term depression (LTD). Each of these proteins is also implicated in schizophrenia risk. In fact, the pathway includes four genes that map to the 108 loci associated with schizophrenia: GRIN2A, nuclear factor of activated T-cells (NFATc3), early growth response 1 (EGR1) and NGFI-A Binding Protein 2 (NAB2); each of which contains the "Index single nucleotide polymorphism (SNP)" (most SNP) at its respective locus. Environmental stimuli activate this biological pathway in neurons, resulting in induction of EGR immediate early genes: EGR1, EGR3 and NAB2. We hypothesize that dysfunction in any of the genes in this pathway disrupts the normal activation of Egrs in response to stress. This may result in insufficient electrophysiologic, immunologic, and neuroprotective, processes that these genes normally mediate. Continued adverse environmental experiences, over time, may thereby result in neuropathology that gives rise to the symptoms of schizophrenia. By combining multiple genes associated with schizophrenia susceptibility, in a functional cascade triggered by neuronal activity, the proposed biological pathway provides an explanation for both the polygenic and environmental influences that determine the complex etiology of this mental illness.

Clozapine for Drug-Refractory Irritability in Individuals with Developmental Disability

OBJECTIVES

In this case series, we describe the acute clinical impact and tolerability of rapid titration of clozapine for treatment of refractory irritability in five hospitalized youth with developmental disability. We offer this descriptive report in an effort to expand the evidence base guiding treatment of refractory aggression in this population.

METHODS

Five youth with developmental disability and severe irritability were admitted to a 10-bed psychiatric crisis stabilization unit where they received thorough psychiatric and medical evaluation. Informed consent was obtained in each case, and each patient underwent rapid titration onto clozapine. Clozapine monitoring guidelines were followed for all patients throughout treatment, and clinical severity at baseline and improvement with treatment was measured by use of the Clinical Global Impressions-Severity scale (CGI-S) and the Clinical Global Impressions-Improvement scale (CGI-I).

RESULTS

One female and four males diagnosed with developmental disability and at least one other psychiatric diagnosis, mean age of 13.1 ± 2.1 years, and mean CGI-S at baseline of 5.8, each received clozapine treatment by rapid titration. The mean therapeutic total daily dose of clozapine was 380 ± 200 mg. All patients demonstrated acute clinical improvement with the mean final CGI-I of 2.0, or "much improved."

CONCLUSION

These initial results support the potential utility of clozapine rapid titration for treatment of severe refractory irritability in youth with developmental disability. These patients tolerated clozapine treatment in the short term. Future studies are needed to thoroughly evaluate the long-term safety of clozapine treatment in this population.

A Retrospective Investigation of Clozapine Treatment in Autistic and Nonautistic Children and Adolescents in an Inpatient Clinic in Turkey

OBJECTIVE

The aim of this retrospective study is to examine the clinical outcomes and safety of clozapine in children and adolescents with schizophrenia or other psychotic disorders/autism spectrum disorder (ASD) or affective disorders.

METHODS

The inpatient and outpatient files of all children and adolescents treated with clozapine over a period of 34 months (from October 2011 to July 2014) were reviewed. Demographic and clinical data were examined to describe clinical and metabolic findings, dosing, and tolerability of clozapine treatment in youth with schizophrenia, other psychotic disorders, ASD, or bipolar disorder.

RESULTS

The 37 pediatric patients included 26 patients with schizophrenia or other psychotic disorders, 7 patients with ASD complicated by schizophrenia or other psychotic disorders or affective disorders, and 4 patients with ASD only. In all groups (n = 37) there was a significant reduction (p < 0.001) in Brief Psychiatric Rating Scale (BPRS) points after clozapine treatment during the inpatient period (38.78 ± 27.75 days). In patients with schizophrenia or other psychotic disorders co-occurring with ASD or not (n = 31), there was a significant improvement in psychotic symptoms according to Positive and Negative Syndrome Scale (PANSS) total scores and subscores (p < 0.001). Of the 26 patients with schizophrenia or other psychotic disorders, 8 (30.8%) showed a positive response (>30% symptom reduction on BPRS). In patients with ASD complicated by schizophrenia or other psychotic disorders or bipolar disorders (n = 7), there was a significant reduction (p = 0.017) in BPRS scores after clozapine treatment. The discontinuation rate for clozapine was 10.8%, and the most frequently observed side effect was hypersalivation (54.1%). Neutropenia associated with clozapine was observed in only one patient (2.7%).

CONCLUSIONS

Clozapine seems to be effective and safe in children and adolescents with schizophrenia or other psychotic disorders co-occuring with ASD or not. There is a need for further studies for determining the efficacy of clozapine in children and adolescents with bipolar affective disorder or ASD.

Use of clozapine in a state child and adolescent psychiatric hospital

We assessed the predictors of clozapine initiation among youth 18 years and younger within a state psychiatric hospital. Administrative data (n = 358) were evaluated of inpatients from a long-term state child and adolescent psychiatric hospital. We investigated 25 background and clinical patient characteristics to determine which factors predicted clozapine initiation following the first 21 days of hospital admission. A Cox proportional model was used to evaluate factors that independently predicted the hazard rate of clozapine initiation. Emergency medication administration during the first 3 weeks of admission, which was more common among the clozapine (84.9 %) than control (61.7 %) patients (p < 0.001), was associated with a significantly increased probability of clozapine initiation (Hazard Ratio = 1.9, 95 % Confidence Interval = 1.2-3.1). Use of a mood stabilizer during the first 3 weeks of the inpatient was non-significantly related to an increased probability of clozapine initiation (Hazard Ratio = 1.7, 95 % Confidence Interval = 1.0-2.9). In this setting, emergency medication use predicts clozapine initiation suggesting that it may be used to treat patients with aggressive behavior.

A systematic review of the evidence of clozapine's anti-aggressive effects

Reducing the risk of violent and aggressive behaviour in patients with schizophrenia remains a clinical priority. There is emerging evidence to suggest that the second-generation antipsychotic, clozapine, is effective at reducing this risk in patients with schizophrenia and some evidence to suggest that it may be best in selected patients. We conducted a systematic literature search in March 2011 of all prospective and retrospective studies, which investigated clozapine's anti-aggressive effects in a variety of mental disorders. The review identified six animal studies, four randomized controlled trials, 12 prospective non-controlled studies and 22 retrospective studies, with four case studies. We found considerable evidence in support of clozapine's ability to reduce violent and aggressive behaviour. Clozapine's anti-aggressive effect was most commonly explored in patients with schizophrenia, with less evidence available for other psychiatric disorders, including borderline personality disorder, autistic spectrum disorders, post-traumatic stress disorder, bipolar disorder and learning disability. There was mixed evidence to address the question of whether or not clozapine was any more effective than other antipsychotics. In the case of schizophrenia, there was evidence to suggest that clozapine's anti-aggressive effect was more marked particularly in those with treatment-resistant illness. Its anti-aggressive effects appeared to be 'specific', being to some extent greater than both its more general antipsychotic and sedative effects. There were significant methodological inconsistencies in the studies we identified, particularly surrounding patient recruitment criteria, the definition and measurement of violence and the lack of randomized, controlled trials. Data on therapeutic monitoring were also limited. Clozapine can reduce violence and persistent aggression in patients with schizophrenia and other psychiatric disorders. It may offer an advantage over other antipsychotics, although perhaps exclusively in the case of traditionally defined 'treatment resistance' or more broadly defined 'complex cases' with co-morbidity. Larger, randomized, blinded, controlled studies with robust characterization of participants, and standardized measures of violence and aggression are, however, needed to fully understand this link and explore the possible mechanisms.

Dopaminergic system genes in childhood aggression: possible role for DRD2

Excessive or deficient levels of extracellular dopamine have been hypothesized to contribute to a broad spectrum of mood, motor, and thought abnormalities, and dopaminergic system genes have been implicated in aggressive behaviour from animal and human studies. OBJECTIVE. We examined selected members of the dopaminergic system genes for association with child aggression.

METHOD

We analyzed polymorphisms in the dopamine transporter DAT1/SLC6A3, dopamine receptor DRD2, and DRD4 genes in our sample of pervasive childhood aggression consisting of 144 cases paired with 144 healthy controls, matched for sex and ethnicity.

RESULTS

Aggressive children were significantly more likely to have the at least one copy of the G allele for the DRD2 A-241G polymorphism (genotypic P=0.02; allelic P=0.01). The DRD2 rs1079598 CC genotype was overrepresented in aggressive children compared to controls (genotype P=0.04). The DRD2 TaqIA T allele (P=0.01) and the TT genotype (P=0.01) were also significantly overrepresented in aggressive children.

CONCLUSIONS

Our preliminary results suggest that three polymorphisms in DRD2 are associated with childhood aggression. Future studies are required to replicate the current results and to further explore the relationship between the dopamine system and aggressive behaviour in children.

Psychopharmacologic control of aggression and violence in children and adolescents

Aggression in children and adolescents is commonly displayed in the community and is even more commonly seen in clinical settings. As symptoms of an underlying disorder, aggressive behaviors should be comprehensively evaluated, and developmental, medical, and substance-use disorders should be identified and treated. This article reviews the most common psychiatric conditions associated with aggression and suggests appropriate psychopharmacologic interventions. Tables with recommended agents for each psychiatric disorder, as well as dosing ranges for each agent, are included.

[Retrospective study of clozapine use in Ile-de-France]

INTRODUCTION

Clozapine, synthesized in the sixties, is an atypical antipsychotic drug whose history has been marked by its haematological toxicity. The purpose of this study was, ten years after it had been replaced at French psychiatrists' disposal, to gather data on the prescription modalities of clozapine, assess whether some factors could affect its efficacy, and describe the population of schizophrenic patients concerned.

METHODOLOGY

Psychiatrists in the Paris region were asked to answer a questionnaire about their patients treated with clozapine. The information collected was about socio-demographic data, history of psychiatric disorder and the way clozapine was used. It was a retrospective study concerning 98 patients.

RESULTS

Subjects were 57 men and 41 women, with a mean age of 38 years. The majority of patients came from metropolitan France. Patients suffered from various clinical subtypes of schizophrenia, as assessed according to DSM IV criteria. Predominant symptomatology during lifetime was most often auditory hallucinations (41%). Mean duration of lifetime neuroleptic treatment was 10.3 years and breaks in follow-up were rare. Mean number of hospitalisations was 6.9 and a little less than half of the patients had been committed involuntarily. Lastly, 38% of patients had attempted suicide at least once and 35% had expressed hetero-agressive behavior. Main indication of clozapine was resistant schizophrenia (88.5% of patients) and mean duration of treatment was 2 years and 4 months. Treatment efficacy was assessed as good or medium in 77.9% of patients, at mean doses (322 mg per day) in keeping with data from the literature. Tolerance was considered on the whole as satisfactory by half of the clinicians. Among the 98 patients of the study, 21.6% had stopped taking clozapine. The reasons for withdrawal were: inefficacy (6.2%), granulopenia (5.2%), epilepsy (1%) and 8.2% for various reasons (half of these cases being non-compliance with treatment). The study of the 5 cases of granulopenia showed that 3 patients had another associated psychotropic medication: 1 patient received only clozapine as monotherapy, 1 data was missing. Two thirds of all patients were receiving another psychotropic drug in association with clozapine, mainly benzodiazepines (18.4%), antidepressants (15.3%) or mood stabilizers (7.1%). The "therapeutic efficacy" variable was compared with some variables in order to isolate factors possibly associated with a better efficacy of clozapine or, on the contrary, with a population of patients poorly responding to treatment. However, no statistically significant difference appeared according to the variables studied, such as gender or lifetime duration of neuroleptic treatment. Moreover, there was no statistically significant difference in efficacy according to schizophrenia subtype, main symptomatology during the course of illness or substance abuse. We studied whether any factor could affect the occurrence of granulopenia. No statistically significant difference was found. The mean age of patients having stopped the treatment because of granulopenia was higher than in the group with other reasons for interruption, but did not reach statistical significance. A trend also appeared towards female predominance (60% of women in the granulopenia group) and 3/4 of patients who had stopped their treatment because of agranulocytosis received another psychotropic drug in association with clozapine.

CONCLUSION

As expected, the main indication for prescribing clozapine was resistant schizophrenia, but contrary to data from the international literature, the efficacy profile was the same whatever the clinical subtype of schizophrenia. The tolerance to clozapine was considered on the whole as satisfactory, but the high proportion of granulopenias leading to treatment withdrawal (5.2% of patients) confirms the need to remain cautious and stresses the importance of regular haematological monitoring. Furthermore, the study of the prescription modalities of clozapine shows that contrary to the guidelines, clozapine is often associated with other psychotropic drugs. In this study, it is striking to note that 75% of granulopenias occurred in a coprescription situation.

Anger and functioning amongst inpatients with schizophrenia or schizoaffective disorder living in a therapeutic community

AIMS

This study explored the functional correlates of anger amongst therapeutic community inpatients.

METHODS

The sample consisted of 44 subjects diagnosed with schizophrenic/schizoaffective disorder who were involved in a community treatment program. Assessment involved administration of the Health of Nation Outcome Scales and the Global Assessment of Functioning as well as self-evaluations using the Social Adaptation Self-evaluation Scale. Psychopathology was assessed with the Positive and Negative Symptoms Scale. Angry feelings and coping skills were self-assessed with the State-Trait Anger Expression Inventory and the Symptom Checklist-90 Hostility Scale. Multiple regression analyses correlated anger with functioning, controlling for psychopathology.

RESULTS

Angry feelings related to self-harm, hyperactivity, physical problems, and to global weight independently from Positive and Negative Symptoms Scale scores. They also predicted interest and pleasure in housekeeping, quality of social relationships and relational exchanges.

CONCLUSIONS

Results showed that angry feelings were not merely derivations of schizophrenic psychopathology; rather, they were independently related to self-damaging behaviors, to attentional demands towards the staff, to agreement to community tasks and to low quality of social relationships. Indeed, anger was related to adaptation's level in a therapeutic community setting demonstrated by subjects with psychoses and it may represent an indirect measure of their experienced quality of life. Therapeutic and management approaches to anger amongst subjects with schizophrenia are discussed.

Mice lacking the immediate early gene Egr3 respond to the anti-aggressive effects of clozapine yet are relatively resistant to its sedating effects

Immediate early genes (IEGs) of the early growth response gene (Egr) family are activated in the brain in response to stress, social stimuli, and administration of psycho-active medications. However, little is known about the role of these genes in the biological or behavioral response to these stimuli. Here we show that mice lacking the IEG transcription factor Egr3 (Egr3-/- mice) display increased aggression, and a decreased latency to attack, in response to the stressful social stimulus of a foreign intruder. Together with our findings of persistent and intrusive olfactory-mediated social investigation of conspecifics, these results suggest increased impulsivity in Egr3-/- mice. We also show that the aggression of Egr3-/- mice is significantly inhibited with chronic administration of the antipsychotic medication clozapine. Despite their sensitivity to this therapeutic effect of clozapine, Egr3-/- mice display a marked resistance to the sedating effects of acute clozapine compared with WT littermate controls. This indicates that the therapeutic, anti-aggressive action of clozapine is separable from its sedating activity, and that the biological abnormality resulting from loss of Egr3 distinguishes these different mechanisms. Thus Egr3-/- mice may provide an important tool for elucidating the mechanism of action of clozapine, as well as for understanding the biology underlying aggressive behavior. Notably, schizophrenia patients display a similar decreased susceptibility to the side effects of antipsychotic medications compared to non-psychiatric controls, despite the medications producing a therapeutic response. This suggests the possibility that Egr3-/- mice may provide insight into the neurobiological abnormalities underlying schizophrenia.

Escalated Aggressive Behavior: New Pharmacotherapeutic Approaches and Opportunities

Psychopharmacologic studies of aggressive behavior in animals under controlled laboratory conditions have been instrumental in developing and evaluating specific and effective novel drug treatments that reduce aggressive behavior. An initial contribution of this research is to create experimental conditions that enable the display of aggressive and defensive acts and postures in species that engage in either dominance or territorial or maternal aggression. Quantitative ethological analyses allow the precise delineation of the sequential organization of aggressive bursts, providing a benchmark for assessing excessive or pathological forms of aggressive behavior. A second contribution of preclinical research is the development of experimental models of escalated forms of aggressive behavior, such as focusing on genetic predispositions or social provocations and frustrative experiences. A critical role of preclinical research is in the pharmacological and neurochemical analysis of aggressive behavior; for example, a host of undesirable side effects prompted a shift from classic dopaminergic neuroleptic compounds to the more recently developed atypical neuroleptics with effective and more specific anti-aggressive effects. The long-established role of brain serotonin in impulsive and escalated forms of aggressive behavior continues to be a focus of preclinical studies. New evidence differentiates dynamic state changes in corticolimbic serotonergic neurons during the termination of aggressive behavior from the deficient-serotonin trait in violence-prone individuals. It can be anticipated that currently developed tools for targeting the genes that code for specific subtypes of serotonin receptors will offer new therapeutic options for reducing aggressive behavior, and the 5-HT(1B) receptor appears to be a promising target. The modulation of GABA and GABA(A) receptors by 5-HT in corticolimbic neurons promises to be particularly relevant for specific forms of escalated aggressive behavior such as alcohol-heightened aggression.

Clozapine: its impact on aggressive behavior among children and adolescents with schizophrenia

OBJECTIVE

To evaluate the effectiveness of clozapine on aggressive behavior for treatment-refractory adolescents (age range 8.5-18) with schizophrenia (295.x) at Bronx Children's Psychiatric Center.

METHOD

Clozapine treatment was administered in an open-label fashion using a flexible titration schedule. The frequency of administration of emergency oral and injectable medications and the frequency of seclusion events 3 months immediately before and from 12 to 24 weeks of clozapine treatment (when optimal clozapine levels were achieved) were compared.

RESULTS

Twenty clozapine-treated children (mean +/- SD dose at week 24, 476 +/- 119 mg) were included. A statistically significant decrease in the frequency of the administration of emergency oral medications, the administration of emergency injectable medications, and seclusion events was found in adolescents during weeks 12 to 24 of clozapine treatment compared with their baseline condition before clozapine initiation.

CONCLUSIONS

These preliminary data indicate the benefits of clozapine treatment in adolescents with treatment-refractory schizophrenia for aggressive behaviors. Although open data limit conclusions from this study, it is important that there was a clinically significant improvement in aggressive behaviors that enabled patients to be discharged to a less restrictive setting. Additional controlled clinical trials of clozapine are needed in treatment-refractory children and adolescents.

The off-label use of clozapine in adolescents with bipolar disorder, intermittent explosive disorder, or posttraumatic stress disorder

OBJECTIVE

There are limited data in the literature regarding clozapine use in adolescents with diagnoses other than schizophrenia. This report describes the use of clozapine in adolescents with diagnoses of bipolar disorder, intermittent explosive disorder (IED), and posttraumatic stress disorder (PTSD).

METHODS

A chart review of 39 adolescents treated with clozapine at two residential facilities was undertaken. Data extraction included demography, illness variables, medication information, and clinical outcomes. Categorical outcomes were analyzed using contingency statistics, and continuous variables were analyzed using a paired t test.

RESULTS

The cohort included 26 females and 13 males with a mean age of 14 years. Clozapine was titrated slowly, and the mean daily dose was 102 mg. The diagnoses included bipolar disorder (n = 7), IED (n = 9), and PTSD (n = 19). There were significant reductions in polypharmacy once the clozapine dosage was stabilized. Prior to clozapine treatment, nearly 70% of the subjects were receiving either mood-stabilizing or antidepressant agents in combination with the previous antipsychotic drug. Once the clozapine dosage was stabilized, only 24% of the subjects required concomitant mood stabilizers (p < 0.001), and only 21% of the subjects required concomitant antidepressants (p < 0.001). Anxiolytic medication use was also significantly reduced during clozapine treatment. Most patients were discharged to a less restrictive setting. Eight subjects discontinued clozapine due to agranulocytosis (n = 1), neutropenia (n = 2), excessive weight gain (n = 2), or not requiring it long term (n = 1), and data were unavailable in 2 subjects. Significant weight gain (5% or greater change from baseline) was noted in 20 subjects.

CONCLUSIONS

Clozapine, in relatively modest doses, appears to have clinical benefits for adolescent with bipolar disorder, IED, and PTSD. There is no labeled indication for clozapine use in these disorders. Clozapine is also associated with serious side effects in subsets of individuals. Therefore, a very careful evaluation of the risk-to-benefit ratio in each individual subject being considered for clozapine is highly recommended.

Benefit-Risk Assessment of Atypical Antipsychotics in the Treatment of Schizophrenia and Comorbid Disorders in Children and Adolescents

Evidence on the efficacy and safety of atypical antipsychotics in children and adolescents with schizophrenia is limited. The purpose of this review is to assess the published data on the use of atypical antipsychotics in children and adolescents with schizophrenia alone and with comorbid disorders, and to establish benefit-risk guidelines for clinicians.Risperidone, olanzapine and clozapine were found to be effective in the treatment of aggression and mania. Risperidone, and possibly also olanzapine, may be the drugs of choice in children with comorbid tic disorders. Ziprasidone has some monoamine reuptake inhibition properties and may be administered as an augmenting agent in children and adolescents with schizophrenia and comorbid anxiety and mood disorders. Compared with the typical antipsychotics, the atypical drugs seem to be more effective, better tolerated and lead to better patient adherence. Importantly, the atypical antipsychotics have a lower propensity to induce extrapyramidal symptoms and a potential (shown so far only in adults) to improve cognitive function and inhibit suicidal behaviour (especially clozapine). Yet, the adverse effects associated with these agents, especially weight gain, which may also have long-term effects, can lead to non-compliance in the young population. In children and adolescents receiving clozapine, olanzapine and quetiapine (but not ziprasidone, which does not have a pro-appetite effect), particularly those with obesity or a family history of diabetes mellitus, fasting blood glucose and lipid levels must be monitored frequently. Weight gain might be better controlled when the children and their parents are properly informed about this adverse effect and diet is regulated. Another major disadvantage of the atypical antipsychotics, especially risperidone, is their association with hyperprolactinaemia, which can lead to hypogonadism-induced osteoporosis, galactorrhoea, gynaecomastia, irregular menstruation and sexual dysfunction, all seen also with typical antipsychotics. Other atypical antipsychotics, namely olanzapine and ziprasidone, have been reported to be prolactin sparing in adults, but may not be completely devoid of hyperprolactinaemic effects in children and adolescents. Thus, prolactin levels should be assessed routinely in young patients treated with atypical antipsychotics. Further, children and adolescents with hyperprolactinaemia-related effects should be switched to a prolactin-sparing agent, such as quetiapine. All atypical antipsychotics may induce sedation and they are not devoid of extrapyramidal symptoms (especially risperidone). The use of typical antipsychotics has been limited to patients who are resistant to atypical antipsychotics, intolerant to their adverse effects, or require injections or depot preparations. Further double-blind, placebo-controlled trials and long-term safety assessments are needed before definitive conclusions can be reached about the place of atypical antipsychotics in the therapeutic armamentarium of childhood-onset schizophrenia.