Clozapine for persons with neurodevelopmental disorders: a systematic review and expert recommendations for clinical practice

INTRODUCTION

We aimed to synthesize the information on the risks and benefits of clozapine prescription for resistant challenging behavior in persons with neurodevelopmental disorders.

METHODS

Articles were identified with MEDLINE, Web of Sciences, and PsycINFO search from inception through January 2024. The review was restricted to persons with intellectual disability (ID) and/or autism spectrum disorder (ASD) without comorbid psychotic or affective disorder. Data were synthesized narratively.

RESULTS

We identified 24 articles (13 case reports, eight chart studies, two controlled studies, one pharmaco-epidemiological study) including 296 patients with ID (n = 222) or ASD (n = 74) (10% aged ≤ 18 years). After clozapine initiation, a decreased frequency of challenging behavior persisting over time was reported in most participants included in clinical studies, and a significant reduction in the number of admissions in the population-based two-year mirror-image study. Adverse drug reactions were those commonly observed with clozapine, i.e. constipation, sedation, and weight gain.

CONCLUSIONS

Since only four participants were included in the controlled studies, the benefits of clozapine in neurodevelopmental disorders are supported by a body of evidence exclusively drawn from observational studies. Further studies are required to clarify the indications of clozapine with respect to the unmet need induced by resistant challenging behavior.

REGISTRATION

PROSPERO database registration number CRD42024522343.

Clozapine for psychotic disorders in adults with intellectual disabilities

BACKGROUND

Psychosis is three times more common in people with an intellectual disability than in those without an intellectual disability. A low intelligence quotient (IQ) is a defining characteristic for intellectual disability and a risk factor for poor outcome in psychosis. Clozapine is recommended for treatment-resistant psychosis. The effect of psychotropic medication can be different in people with intellectual disability; for example, they may be more prone to side effects. People with an intellectual disability and psychosis form a special subgroup and we wanted to examine if there is randomised controlled trial (RCT) data in this population to support the use of clozapine.

OBJECTIVES

To determine the effects of clozapine for treating adults with a dual diagnosis of intellectual disability and psychosis.

SEARCH METHODS

We searched CENTRAL, Ovid MEDLINE, Embase and eight other databases up to December 2014. We also searched two trials registers, the Cochrane Schizophrenia Group's Register of Trials, and contacted the manufacturers of clozapine.

SELECTION CRITERIA

RCTs that assessed the effects of clozapine, at any dose, for treating adults (aged 18 years and over) with a dual diagnosis of intellectual disability and psychotic disorder, compared with placebo or another antipsychotic medication.

DATA COLLECTION AND ANALYSIS

Three review authors independently screened all titles, abstracts and any relevant full-text reports against the inclusion criteria.

MAIN RESULTS

Of the 1224 titles and abstracts screened, we shortlisted 38 full-text articles, which we subsequently excluded as they did not meet the inclusion criteria. These studies were not RCTs. Consequently, no studies are included in this Cochrane review.

AUTHORS' CONCLUSIONS

There are currently no RCTs that assess the efficacy and side effects of clozapine in people with intellectual disabilities and psychoses. Given the use of clozapine in this vulnerable population, there is an urgent need for a RCT of clozapine in people with a dual diagnosis of intellectual disability and psychosis to fill the evidence gap.

The use of clozapine among individuals with intellectual disability: a review

Clozapine has been approved in the United States since 1990 for refractory or treatment resistant schizophrenia in the general population. However, as with many other antipsychotic medications, it is being prescribed for reasons other than those indicated. Among individuals with intellectual disabilities, clozapine is increasingly being prescribed to treat behavioral problems, although the empirical evidence for such a practice is lacking. This review was undertaken as an attempt to summarize the available studies regarding the use of clozapine for behavioral purposes among individuals with intellectual disabilities. Findings of our review suggest that the effectiveness of clozapine in targeting challenging behaviors among individuals with intellectual disabilities is relatively inconclusive at present. We discuss reasons why these limitations exist and offer some solutions to help alleviate these limitations.

[Self-injurious-behavior in children and adolescents with intellectual disabilities]

10% of the children and teenagers with intellectual disability develop self-injurious behavior during lifespan. The causes for this are investigated, often various and reach from learn-theoretical up to neurobiological conditions. The available work gives overview of the current state of research to the etiology, further factors of influence as well as the process of self-injurious behavior by intellectual disability. Beyond that current diagnostics procedures, standard of treatment of the last thirty years and their effectiveness are presented and discussed finally.

Guidelines for the use of clozapine in individuals with developmental disabilities

Clozapine is the most effective antipsychotic medication currently in use, but there has been a paucity of well-controlled research on its efficacy with people with developmental disabilities. We present a set of guidelines to ensure proper utilization of clozapine in individuals with developmental disabilities, because it can offer them therapeutic advantages similar to those observed in people with schizophrenia. We provide recommendations regarding the use of clozapine that are based on three main sources: literature and published professional practice guidelines regarding the use of clozapine in individuals who do not have developmental disabilities, the limited literature on the use of clozapine in individuals who have developmental disabilities, and our own clinical experience. The first part of the guidelines contains an overview of necessary practical knowledge regarding side effects, dose and blood level considerations, and interactions with other medications, diet and tobacco smoking. In the second part, we offer procedures for selecting individuals for clozapine therapy based on proper indications and contraindications for treatment. We also include requirements regarding informed consent, dosage and special laboratory and clinical monitoring.

Self-injurious behavior and the efficacy of naltrexone treatment: a quantitative synthesis

People with mental retardation, autism, and related developmental disabilities who self-injure are treated with a wide array of behavioral techniques and psychotropic medications. Despite numerous reports documenting short-term and some long-term changes in self-injury associated with the opiate antagonist naltrexone hydrochloride, no quantitative review of its efficacy has been reported. We conducted a quantitative synthesis of the peer-reviewed published literature from 1983 to 2003 documenting the use of naltrexone for the treatment of self-injurious behavior (SIB). Individual-level results were analyzed given subject and study characteristics. A sample of 27 research articles involving 86 subjects with self-injury was reviewed. Eighty percent of subjects were reported to improve relative to baseline (i.e., SIB reduced) during naltrexone administration and 47% of subjects SIB was reduced by 50% or greater. In studies reporting dose levels in milligrams, males were more likely than females to respond. No significant relations were found between treatment outcomes and autism status or form of self-injury. Results are discussed with respect to future efficacy work related to study outcomes and the pharmacological treatment of self-injury.

The use of clozapine in adults with intellectual disability

BACKGROUND

There are not many studies on the use of clozapine in patients with intellectual disability (ID). The authors describe a case series of patients treated with clozapine, drawn from a medium secure unit, a low secure assessment and treatment service and a community team in the London region.

METHOD

A retrospective file-review of patients treated in these three settings during the time period March-June 2002 was performed (n = 24). Information was collected using a semistructured proforma.

RESULTS

Of the 24 patients, 67% had schizophrenia, 17% had schizoaffective disorder and 8% had bipolar disorder. Patients had been unwell for a mean of 6 years and had been tried on a mean of four antipsychotics. The mean maximum dose of clozapine was 488 mg. The outcomes on the clinical global impression (CGI) scale showed 29% very much improved, 42% much improved, 21% minimally improved and 8% no change. 54% of the whole sample and 53% of those from the medium secure unit were discharged to homes in the community. The drug had to be stopped in four patients, of which three were because of neutropaenia.

CONCLUSION

Clozapine appears to be safe and efficacious in many people with ID. Careful monitoring of side-effects is needed during therapy.

Antipsychotic medication for challenging behaviour in people with learning disability

BACKGROUND

The term 'challenging behaviour', in the absence of psychiatric disorder, encompasses a wide range of behaviours that may be harmful to people or property, may be difficult to manage and may limit access to community facilities. Antipsychotic medications have been used to modify such behaviours in people with learning disability, but there is little evidence to suggest that the benefits outweigh the risks.

OBJECTIVES

To determine the effectiveness of antipsychotic medication for people with learning disability and challenging behaviour without additional mental illness.

SEARCH STRATEGY

Biological Abstracts, the Cochrane Library, EMBASE, MEDLINE, PsycINFO and BIOSIS were searched. Further references were sought from published trials and pharmaceutical companies. Trials were reliably identified and data extracted.

SELECTION CRITERIA

All randomised controlled trials of antipsychotic medication versus placebo.

DATA COLLECTION AND ANALYSIS

Reviewers independently evaluated and analysed data on an intention to treat basis. Data were evaluated at 4, 8 and 12 weeks as longer follow-up data were not available. Reviewers assumed that those subjects lost to follow-up had a bad outcome.

MAIN RESULTS

Only nine randomised controlled trials could be included in the analyses. These provided no evidence of whether antipsychotic medication helps or harms adults with learning disability and challenging behaviour.

REVIEWERS' CONCLUSIONS

There are limited data on this important issue and more research is urgently needed.

Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation (DC-LD) and psychiatric phenotypes

BACKGROUND

The concept of behavioural phenotypes is reviewed, with emphasis on the need to research reasons for heterogeneity.

METHODS/RESULTS

The classification of emotional, behavioural, linguistic and cognitive abnormalities associated with genetic disorders may be improved through the use of the Diagnostic Criteria for Psychiatric Disorders for Use with Adults with Learning Disabilities/Mental Retardation.

CONCLUSIONS

Examples of such abnormalities are discussed, showing how more accurate descriptions can result in improved diagnosis and treatment.

Self-injurious behavior in rhesus monkeys: new insights into its etiology, physiology, and treatment

Self-injurious behavior (SIB) is a significant human health problem frequently associated with profound intellectual disabilities, genetic diseases, and psychiatric conditions. However, it also occurs in subclinical populations and appears to be on the rise in adolescents and young adults. SIB is also seen in a small percentage of nonhuman primates that injure themselves through biting. We have begun to characterize SIB in rhesus monkeys to identify some of the risk factors associated with this disorder, and to determine the parallels with the human condition. In our study population, 14% of individually housed monkeys (the vast majority of which are males) have a veterinary record for self-inflicted wounding. Wounding is rare, but self-directed biting is common. SIB can be elicited during aggressive altercations and may be associated with husbandry events. Some monkeys appear to be more vulnerable to acquiring SIB. This increased vulnerability is associated with certain social experiences in the first 2 years of life and with exposure to a larger number of moderately stressful events as compared to controls. Monkeys with SIB also have a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, indicated by a blunted cortisol response to mild stressors. Our findings suggest that SIB may be a coping strategy to reduce arousal. Biting appears to rapidly lower an escalating heart rate. The potentially reinforcing effects of SIB may account for the failure of some treatment regimens. These findings are compared to studies of SIB in humans, and concordances are identified.

Self-injurious behaviour before and after deinstitutionalization

The deinstitutionalization movement is presently spreading in Europe. Studies evaluating the effects of deinstitutionalization on behaviour disturbances among people with intellectual disability (ID) have been inconclusive. The present paper focuses on people without self-injurious behaviour (SIB) who developed SIB after deinstitutionalization. The present authors studied individual and environmental characteristics before and after deinstitutionalization to look for factors associated with the development of SIB which could also be possible intervention points for preventive action. All those individuals in an institution for people with ID who did not have SIB before deinstitutionalization were included in the present study. The individuals who developed SIB after deinstitutionalization (n = 15) formed the study group (group A) and those who did not (n = 53) comprised the control group (group B). The population was examined both before and after deinstitutionalization. As far as possible, the same methods were used at both occasions. The covariates were both individual (e.g. mental health, behaviour disturbances and behaviour deficits) and environmental (e.g. caretaker education, caretaker:patient ratio, housing and leisure activities). Psychiatric disorders were identified in 1987 and 1995 with the Psychopathology Instrument for Mentally Retarded Adults, which was filled in by the caretakers. In 1987, the people in group A who acquired SIB had lower developmental quotients, used wheelchairs more often and had trouble with moving around without help. They also had a greater frequency of epileptic seizures, and hearing and communication impairment. In 1995, there were only minor environmental differences between groups A and B. There were significantly more individuals involved in the rotation period and more unskilled caretakers working with the people in group A than group B. The present authors found no differences between the two groups on variables such as global mental health and behaviour disturbances, or in the use of neuroleptics before or after deinstitutionalization. Groups A and B did not show differences in behaviour disturbances or psychiatric disorders in 1987. In both 1987 and 1995, there were no differences between groups A and B on variables such as accommodation, caretaker:patient ratio, the number of caretakers involved in direct care, the caretakers' education, or the time spent in structured activities before and after deinstitutionalization. The individual characteristics indicating that a person may acquire SIB are behaviour deficits which are suggestive of central nervous system dysfunction or damage, even if the results are inconclusive. The development of SIB may also be facilitated by communication deficits or by reinforcement of a incidentally occurring SIB if the staff includes many unskilled caretakers in the rotation period.

Olanzapine for chronic, stereotypic self-injurious behaviour: a pilot study in seven adults with intellectual disability

Dopamine one (D1) receptor supersensitvity in the corpus striatum is said to be the primary mechanism within the dopamine model proposed for chronic, refractory self-injurious behaviour (SIB), which may explain why conventional neuroleptics have proven largely ineffective. In common with other atypical antipsychotic agents, olanzapine has more affinity for the D1 receptor. The present study explored whether olanzapine could reduce rates of the stereotypic form of chronic SIB, a subtype where dopamine dysfunction is the most likely underlying mechanism. A clinical sample of seven patients with various levels of learning disability who displayed features of stereotypic SIB were assessed over a 6-week period of baseline measurement and a 15-week treatment phase during which olanzapine was added to existing medication. Both SIB and other aberrant behaviours were measured by daily nurse rating and the Self-Injury Trauma Scale (SITS). All measurements were unblind. Doses ranged from 5 to 15 mg. Out of the seven subjects, three showed a clear improvement, one showed a marginal improvement, one deteriorated, and the data was equivocal for the remaining two individuals. The means of the SITS Number and Severity Indices (NI and SI, respectively) reduced significantly from baseline during both the 5- and 10-mg treatment phases, and taking treatment as a whole, by 53% and 48%, respectively (NI: mean = 0.7 units reduction, P = 0.02; SI: mean = 0.9 units reduction, P = 0.04). The risk index also reduced, but did not reach significance. A modest reduction in mean nurse-rated SIB was not significant for either phase or for treatment as a whole. At doses above 5mg, mean scores deteriorated on balance, although two responders showed a marginal additional improvement. Olanzapine was well tolerated with one adverse event reported (somnolence) which was mild and transient. The present pilot study suggests that olanzapine can reduce stereotypic SIB. A larger trial is indicated.

Self-injurious behavior and sleep disturbance in adults with developmental disabilities

Sleep patterns of 30 individuals with self-injurious behavior and mental retardation were compared with those of 30 matched controls residing in the same residential facility that did not self-injure. Individuals were recorded as asleep or awake during 30 min intervals for eight hours per night. The results of a Wilcoxon signed-ranks test (p < .05) indicated that individuals with self-injury slept significantly less than individuals without self-injury. chi2 analyses (p < .01) indicated significantly greater variability in the number of intervals recorded as asleep among individuals with self-injury than their matched controls. These results are congruent with previous findings of sleep disturbance among persons with mental retardation and behavior problems. The possibility of neurochemical dysregulation in sleep disturbance among individuals with daytime self-injury is discussed.

Antipsychotic medication for challenging behaviour in people with learning disability

BACKGROUND

The term 'challenging behaviour', in the absence of psychiatric disorder, encompasses a wide range of behaviours that may be harmful to people or property, may be difficult to manage and may limit access to community facilities. Antipsychotic medications have been used to modify such behaviours in people with learning disability, but there is little evidence to suggest that the benefits outweigh the risks.

OBJECTIVES

To determine the effectiveness of antipsychotic medication for people with learning disability and challenging behaviour.

SEARCH STRATEGY

Biological abstracts, the Cochrane Library, the Cochrane Schizophrenia Group's Register, EMBASE, MEDLINE, PsycLIT were searched. Further references were sought from published trials and pharmaceutical companies. Trials were reliably identified and data extracted.

SELECTION CRITERIA

All randomised controlled trials of antipsychotic medication versus placebo.

DATA COLLECTION AND ANALYSIS

Reviewers independently evaluated and analysed data on an intention to treat basis. Data were evaluated at 4 and 8 weeks as longer follow-up data were not available. Reviewers assumed that those subjects lost to follow-up had a bad outcome.

MAIN RESULTS

Only three randomised controlled trials could be included in the analyses. These provided no evidence of whether antipsychotic medication helps or harms adults with learning disability and challenging behaviour.

REVIEWER'S CONCLUSIONS

There is limited data on this important issue and more research is urgently needed.

Psychopharmacotherapy in children and adults with intellectual disability

The prevalence of psychiatric disorders is increased in children and adults with intellectual disability. Brain damage or dysfunction interact with social and family factors to increase susceptibility to mental illness. Psychiatric disorders in the context of genetic syndromes are commonly overlooked, and there is substantial underdiagnosis of mental disorders because of the atypical and non-specific clinical presentations, and the frequent assumption that psychiatric symptoms are an inherent part of the underlying intellectual disability. There is a strong need for evidence-based practice in the prescribing and monitoring of drugs in this population, especially since many of the drugs are unlicensed for use in children. There is an urgent need to understand and establish the pharmacokinetics, pharmacodynamics, and side-effect profiles of psychotropic medication in this population. Positive trends in pharmacotherapy include the use of atypical antipsychotics instead of the classic antipsychotics, serotonin-specific reuptake inhibitors (SSRIs) rather than tricyclic antidepressants, and newer antiepileptic drugs. Another welcome trend is the use of SSRIs instead of antipsychotics in the long-term management of challenging behaviour in this population.

Psychopharmacology of severe self-injury associated with learning disabilities

BACKGROUND

Many sedative and antipsychotic agents have been used in the management of severe self-injury associated with learning disabilities. Their efficacy has been questioned. Recent research has identified some biological abnormalities associated with severe self-injury and allowed a more rational selection of treatment.

METHOD

Review of published literature, including trials, previous reviews and case reports.

REPORTS

There is evidence for the efficacy of opiate antagonists in the management of severe self-injury, and recent research has identified potential methods of predicting treatment response. Dopamine D1 antagonists and some agents affecting serotonin turnover may also be of benefit.

CONCLUSIONS

More rational psychopharmacological treatments for severe self-injurious behaviour may become available. Such treatments are difficult to evaluate for methodological and ethical reasons. They usually involve the clinical use of compounds for unlicensed indications, rather than trials of agents developed specifically to treat severe self-injurious behaviour. Combining psychopharmacological and psychological interventions may provide additional benefits.