Pharmacological treatment of mood disturbances, aggression, and self-injury in persons with pervasive developmental disorders

Aggression, self-injury, and mood disturbances in persons with autistic disorders, while not uncommon, do not constitute core features of autism. Moreover, these problems can occur for a variety of reasons, which need to be assessed in order to plan appropriate and frequently combined (behavioral-pharmacological) treatments. Drugs acting primarily in the dopaminergic, serotonergic, adrenergic, opioidergic, and glutamatergic systems all have been explored in the treatment of aggression and self-injury. While no single drug or class of medication has yet emerged as consistently effective, a number of drugs appear promising. Advances in the assessment of aggressive behaviors, the identification of predictors of drug response, and additional controlled clinical drug trials specifically aimed at these target behaviors are essential in improving the approach to these problematic behaviors in the context of autistic disorder.

Dopaminergic and glutamatergic interactions in the expression of self-injurious behavior

Self-injurious behavior occurring in persons with severe mental retardation is a clinically significant and poorly understood problem. Multiple neurotransmitter systems have been implicated in the pathogenesis of this behavior, particularly dopaminergic, opioidergic, and serotonergic systems. Pemoline, a central stimulant, administered systemically at high doses reliably produces self-biting behavior in the rat. The systemic bolus of pemoline produces sustained neostriatal levels of pemoline for over 24 h in a continuous infusion paradigm. Studies of the effect of cortical lesions on pemoline-mediated behaviors reveal that cortical damage, as is common in profound mental retardation, lowers the threshold for pemoline-induced self-biting behavior. Data from the corticostriatal slice suggests that sustained exposure to pemoline produces a shift in N-methyl-D-aspartate receptor-mediated responses rendering them more susceptible to dopaminergic enhancement. Thus, dopaminergic and glutamatergic interactions appear to play an important role in the development and expression of self-biting in the pemoline model.

Carbamazepine reduces dopamine-mediated behavior in chronic neuroleptic-treated and untreated rats: implications for treatment of tardive dyskinesia and hyperdopaminergic states

Chronic treatment with neuroleptic drugs such as haloperidol (HAL) can result in a syndrome of abnormal involuntary movements known as tardive dyskinesia (TD). The authors have obtained evidence that TD in humans is reduced in patients also taking anticonvulsant drugs, primarily carbamazepine (CBZ). To test for a causal role of CBZ in this effect, the authors quantified abnormal movements elicited by dopamine (DA) receptor stimulation in rats (Rattus norvegius) withdrawn from chronic treatment with HAL or CBZ alone or in combination. The expected increased behavioral responsiveness to combined D1/D2 stimulation in rats treated with HAL for 8 weeks was significantly attenuated by chronic CBZ, which also attenuated behavioral responsiveness in otherwise untreated rats. Striatal D2 DA receptor density was elevated in rats treated chronically with HAL but unaffected by CBZ. Striatal D1 DA receptor density was elevated by chronic CBZ but unaffected by HAL. These findings suggest that by reducing DA supersensitivity, CBZ may be useful in treating TD and other hyperdopaminergic states.

Pharmacologic management of psychiatric and behavioral symptoms in mental retardation

Compared with the general population, individuals with mental retardation demonstrate more susceptibility to psychiatric illness and may display disruptive behaviors. These symptoms significantly can affect an already compromised ability to function and the patient may benefit from pharmacologic intervention. Clinical characteristics of individuals with mental retardation warrant special consideration regarding diagnosis and treatment of their psychiatric and behavioral problems. This article describes the nature of symptoms that are typically the target of pharmacologic intervention, outlines special diagnostic considerations, and examines recent findings and experience with psychotropic medication in mental retardation.

Practice parameters for the assessment and treatment of children, adolescents, and adults with mental retardation and comorbid mental disorders. American Academy of Child and Adolescent Psychiatry Working Group on Quality Issues

Mental retardation (MR) is a heterogeneous condition defined by significantly subaverage intellectual and adaptive functioning and onset before age 18 years. With an approach underscored by principles of normalization and the availability of appropriate education and habilitation, persons with MR generally live, are educated, and work in the community. Mental disorders occur more commonly in persons with MR than in the general population. However, the disorders themselves are essentially the same. Clinical presentations can be modified by poor language skills and by life circumstances, so a diagnosis might hinge more heavily on observable behavioral symptoms. The diagnostic assessment considers and synthesizes the biological, psychological, and psychosocial context of mental disorders. Comprehensive treatment integrating various approaches, including family counseling, pharmacological, educational, habilitative, and milieu interventions is the rule.

Summary of the Practice Parameters for the Assessment and Treatment of Children, Adolescents, and Adults with Mental Retardation and Comorbid Mental Disorders. American Academy of Child and Adolescent Psychiatry

This summary provides an overview of the assessment and treatment recommendations contained in the Practice Parameters for the Assessment and Treatment of Children, Adolescents, and Adults With Mental Retardation and Comorbid Mental Disorders. The parameters were written to aid clinicians in the assessment and treatment of children, adolescents, and adults with symptoms of mental retardation (MR) and comorbid mental disorders. MR is a heterogeneous condition defined by significantly subaverage intellectual and adaptive functioning and onset before age 18 years. With an approach underscored by principles of normalization and the availability of appropriate education and habilitation, persons with MR generally live, are educated, and work in the community. Mental disorders occur more commonly in persons with MR than in the general population. However, the disorders themselves are essentially the same. Clinical presentations can be modified by poor language skills and by life circumstances, so a diagnosis might hinge more heavily on observable behavioral symptoms. The diagnostic assessment considers and synthesizes the biological, psychological, and psychosocial context of mental disorders. Comprehensive treatment integrating various approaches, including family counseling, pharmacological, educational, habilitative, and milieu interventions is the rule.

Obsessive-compulsive symptoms in Prader-Willi and "Prader-Willi-Like" patients

OBJECTIVE

To compare obsessive-compulsive (OC) symptoms in patients with Prader-Willi syndrome (PWS) and symptoms in a group of patients presenting with "Prader-Willi-like" features but without the genetic abnormalities associated with PWS.

METHOD

16 patients aged 4 through 20 years were evaluated in a clinic specializing in the assessment and management of behavioral and food-related problems in PWS. Eight patients were found to have key features of the syndrome but did not have a PWS genotype. These PWS-like subjects were matched to 8 clinic patients with a confirmed deletion of the PWS critical region of the paternally derived chromosome 15. All subjects were evaluated for obesity, IQ, food-related problems, maladaptive behaviors, and non-food-related OC symptoms.

RESULTS

There were no differences between the 2 groups with respect to measures of obesity, IQ, food-related difficulties, or overall maladaptive behaviors. The PWS group showed significantly greater numbers of OC symptoms and greater symptom severity.

CONCLUSIONS

Patients with PWS have elevated numbers of OC symptoms and significant symptom-related impairment which are not explained by developmental delay, food-related difficulties, or obesity. OC symptoms are part of a behavioral phenotype that accompanies deletions on the proximal long arm of chromosome 15 in PWS.

Cortical damage enhances pemoline-induced self-injurious behavior in prepubertal rats

Self-injurious behavior (SIB) is a devastating characteristic of several developmental disorders including a number of mental retardation syndromes. The functional neuroanatomy and neuropharmacology of SIB is not well understood. Self-biting behavior (SBB) can be induced in rats by a high dose, systemic injection of pemoline (250 mg/kg, SC). This animal model allows for the investigation of anatomical and pharmacological aspects of SIB. Cortical pathology is a common occurrence in human disorders with SIB, and may be a fundamental pathological factor in producing the behavior. The present experiment was designed to investigate the effects of cortical damage on pemoline-induced SBB in prepubertal rats. Bilateral cortical aspirations were performed in 3-5-week-old rats. One week postsurgery, a pemoline challenge was administered. Behavioral comparisons were completed between the lesion group and an anesthetized-only control group. Results indicated that cortical damage significantly enhanced pemoline-induced SBB, along with some of the other pemoline-induced stereotypical behaviors. These results support the hypothesis that cortical damage influences the expression of stimulant-induced self-injury, and potential mechanisms for this influence are suggested.

Maladaptive behavior differences in Prader-Willi syndrome due to paternal deletion versus maternal uniparental disomy

Maladaptive behavior was compared across 23 people with Prader-Willi syndrome due to paternal deletion to 23 age- and gender-matched subjects with maternal uniparental disomy. Controlling for the higher IQs of the uniparental disomy group, deleted cases showed significantly higher maladaptive ratings on the Child Behavior Checklist's Internalizing, Externalizing, and Total domains as well as more symptom-related distress on the Yale-Brown Obsessive-Compulsive Scale. Across both measures, deleted cases were more apt to skin-pick, bite their nails, hoard, overeat, sulk, and withdraw. A dampening of symptom severity is suggested in Prader-Willi syndrome cases due to maternal uniparental disomy. Findings are compared to Angelman syndrome, and possible genetic mechanisms are discussed, as are implications for Prader-Willi syndrome and obsessive-compulsive behaviors.

Open-label olanzapine treatment in five preadolescent children

Olanzapine is a recently introduced atypical neuroleptic agent for which little information is available on its use in children. Open clinical trials of olanzapine treatment were conducted on five hospitalized children (ages 6 to 11 years) with varying diagnoses including bipolar disorder, psychosis not otherwise specified, schizophrenia, and attention-deficit/ hyperactivity disorder. Each patient had failed previous psychotropic medication trials, with a mean of four prior trials. The mean length of olanzapine treatment was 32 days (range, 2 to 7 weeks), and mean daily dose was 7.5 mg/day (range, 2.5 to 1.0 mg/day) or 0.22 mg/kg/day (range, 0.12 to 0.29 mg/kg/day). All children experienced adverse effects, including sedation (N = 3), weight gain of up to 16 pounds (N = 3), and akathisia (N = 2). Three patients showed some clinical improvement, but olanzapine treatment was discontinued in all five children within the first 6 weeks of treatment because of adverse effects or lack of clinically significant therapeutic response, although higher (or lower) doses, slower titration of dosage, or a longer duration of treatment might have produced more favorable results. Psychotic symptoms did not respond in the two patients with evidence of overt hallucinations and paranoid ideation. Improvement was observed in sleep in all five patients and in control of aggression in three. Before controlled trials of olanzapine in children are undertaken, further exploration of dose range and increased duration of treatment on an open basis are warranted. Until more encouraging data are available, clinicians should be cautious and conservative in their predictions about the potential value of olanzapine in treating preadolescent psychiatric disorders.

Molecular screening for proximal 15q abnormalities in a mentally retarded population

Paternal or maternal deletions in the 15q11.2-q13 region are known to result in Prader-Willi syndrome (PWS) or Angelman syndrome (AS), respectively. Maternal duplications in 15q11.2-q13 have been found in patients with autism. A population of adults with moderate to profound mental retardation was studied to examine the usefulness of PCR based molecular methods in screening for proximal chromosome 15 abnormalities. Two hundred and eighty-five subjects were initially screened at five microsatellite markers with average heterozygosity values of 0.74 (range 0.54-0.82). Of these subjects, four had a single allele at all five loci, suggestive of a deletion or uniparental isodisomy. The four samples were further screened with additional markers located within 15q11.2-q13 as well as markers telomeric to this region. One subject had uniparental disomy (UPD) and three subjects had a deletion. To determine the parental origin of the 15q11-q13 region containing the single haplotype, samples were analysed with a newly developed methylation specific PCR technique at the SNRPN locus. Each of the four subjects showed presence of the paternal allele and absence of the maternal allele. All cases had a phenotype consistent with Angelman syndrome as expected for the level of mental retardation, but the subject with UPD was distinct from the other subjects with an absence of a history of seizures and presence of bilateral undescended testes and Parkinsonism. Although Angelman syndrome has an estimated population prevalence of 0.008%, at least 1.4% of the moderately to profoundly mentally retarded subjects screened were found to have Angelman syndrome.

Association of an X-chromosome dodecamer insertional variant allele with mental retardation

Mental retardation is a prominent feature of many neurodevelopmental syndromes. In an attempt to identify genetic components of these illnesses, we isolated and sequenced a large number of human genomic cosmid inserts containing large trinucleotide repeats. One of these cosmids, Cos-4, maps to the X-chromosome and contains the sequence of a 7.3-kb mRNA. Initial polymorphism analysis across a region of repetitive DNA in this gene revealed a rare 12-bp exonic variation (<< 1% in non-iII males) having an increased prevalence in non-Fragile X males with mental retardation (4%, P < 0.04, n = 81). This variant was not present in the highly conserved mouse homologue that has 100% amino acid identity to the human sequence near the polymorphism. Subsequent screening of two additional independent cohorts of non-Fragile X mentally retarded patients and ethnically matched controls demonstrated an even higher prevalence of the 12-bp variant in males with mental retardation (8%, P < 0.0003, n = 125, and 14%, P < 0.10, n = 36) vs the controls. Multivariate analysis was conducted in an effort to identify other phenotypic components in affected individuals, and the findings suggested an increased incidence of histories of hypothyroidism (P < 0.001) and treatment with antidepressants (P < 0.001). We conclude that the presence of this 12-bp variant confers significant susceptibility for mental retardation.

Paroxetine treatment of aggression and self-injury in persons with mental retardation

An open, prospective assessment of the treatment of severe aggression and self-injurious behavior (SIB) with paroxetine, a serotonin re-uptake inhibitor, in 15 institutionalized persons with mental retardation was undertaken. Frequency and severity of aggression and SIB were charted by trained staff members. Only aggression severity was reduced over the entire 4-month follow-up period. Within the limits of an open trial, this effect was significant at one month but did not remain significant subsequently. The apparent diminution of effectiveness after 4 weeks of treatment may suggest adaptive changes warranting further study.

Pemoline alters dopamine modulation of synaptic responses of neostriatal neurons in vitro

Pemoline, a central stimulant, administered systemically at high doses (300 mg/kg) reliably produces self-biting behavior in rats. Pemoline-induced self-biting shares many similarities with self-injury seen in certain human disorders. Recent evidence has shown that alterations in neostriatal neurochemistry accompany the self-biting behavior seen in the rat. The present study used intracellular electrophysiological techniques to reveal changes in neostriatal cellular physiology in slices from rats which had displayed self-injury. Depolarizing postsynaptic potentials (DPSPs) were examined in neostriatal slices from rats that received pemoline and had been engaging in self-injurious behavior and from two control populations: rats that received the same concentration of pemoline and did not engage in self-biting, and rats that received vehicle alone (peanut oil). Data were acquired in standard artificial cerebral spinal fluid. DPSPs were evoked by cortical electrical stimulation in the slice. In neurons from rats that received the vehicle or that had received pemoline but had not engaged in self-injury, dopamine (DA, 20 microM) application produced a significant decrease in the size of the cortically evoked neostriatal DPSP. In contrast, DA application produced an increase in DPSP size in neurons from rats which had received pemoline and had engaged in self-injury. Bath application of a combination of D1 and D2 receptor agonists best replicated the enhancing effect of DA. Furthermore, the enhancement could be blocked by pretreatment with the competitive N-methyl-d-aspartate receptor antagonist, 2-amino-5-phosphonopentanoic acid. The results indicate that alterations in neostriatal DA-glutamate interactions accompany pemoline injections which produce self-injurious behavior.

Mental retardation: a review of the past 10 years. Part I

OBJECTIVE

To review the literature over the past decade on mental retardation, particularly as regards its definition, prevalence, major causes, and associated mental disorders.

METHOD

A computerized search was performed for articles published in the past decade, and selected papers were highlighted.

RESULTS

The study of mental retardation has benefited considerably by advances in medicine generally and by developments in molecular neurobiology in particular. Increasing awareness of psychiatric comorbidity in the context of intellectual disability highlights the need for studies of the phenomenology and treatment of mental disorders in this population.

CONCLUSIONS

Although the study of developmental disorders has advanced significantly over the past decade, considerable work remains. Mental retardation is a model for the utility of the biopsychosocial approach in medicine.

Mental retardation: a review of the past 10 years. Part II

OBJECTIVE

To review the literature over the past decade on mental retardation, particularly with respect to genetics and behavioral phenotypes.

METHOD

A computerized search was performed for articles published in the past decade, and selected papers were highlighted.

RESULTS

The study of mental retardation has benefited considerably by advances in medicine generally, and by developments in molecular neurobiology in particular. These advances in genetics have led to new insights regarding the causes of mental retardation, as well as a growing appreciation of behavioral phenotypes associated with some mental retardation syndromes.

CONCLUSIONS

Although the study of developmental disorders has advanced significantly over the past decade, considerable work remains. Mental retardation should remain the model for the utility of the biopsychosocial approach in medicine.

Pemoline produces ipsilateral turning behavior in unilateral 6-OHDA-lesioned rats

1. Male Sprague-Dawley rats received either a unilateral injection of 6-hydroxy-dopamine or vehicle injection into the medial forebrain bundle. 2. Two weeks post surgery, all rats received a pemoline challenge (250 mg/kg s.c.), and rotational and stereotyped behaviors were videotaped and analyzed. 3. All rats regardless of injection expressed stereotyped behaviors and hyper-locomotion after pemoline challenge. 4. High performance liquid chromatography (HPLC) with electrochemical detection was used to evaluate changes in the levels of dopamine, serotonin and their metabolites in neostriata. 5. Rats with dopamine depleting lesions exhibited ipsilateral rotational behavior, indicating that pemoline, a central stimulant, is an indirect dopamine agonist in the rat. 6. The extent of dopamine depletion and serotonin elevation in the neostriatum in lesioned animals was related to the expression and degree of rotational behavior.

Open trial lamotrigine in the treatment of self-injurious behavior in an adolescent with profound mental retardation

This single case reports an open trial of lamotrigine in the treatment of self-injurious behavior (SIB) and epilepsy in an 18-year-old female diagnosed with generalized seizure disorder, stereotypic movement disorder, and compulsive SIB in the context of profound mental retardation. Animal models of SIB suggest that the glutamate neurotransmitter systems, involved in the generation of epileptic seizures, may also have a role in the pathophysiology of SIB. Data suggesting that lamotrigine may decrease glutamate release encouraged an empirical trial of lamotrigine for treatment of SIB. After 4 weeks of treatment of lamotrigine 200 mg daily, decreases in agitation and fearfulness were clinically observed, along with a 50% reduction in the frequency of SIB as measured by standardized scales. Good seizure control was maintained throughout the trial. No significant adverse effects were observed. Positive effects persisted at 1-year follow-up. Symptoms of stereotypic movement disorder appeared unchanged. Because these findings are preliminary, no clinical recommendations for the treatment of SIB with lamotrigine can be made until controlled studies have been completed.

Pretreatment with MK-801 inhibits pemoline-induced self-biting behavior in prepubertal rats

The indirect dopamine agonist, pemoline (120-300 mg/kg s.c.), can induce self-biting behavior in the rat. The present study demonstrates that the non-competitive N-methyl-D-aspartate (NMDA) antagonist, dizocilpine (MK-801, 0.2 mg/kg s.c.), significantly attenuates pemoline-induced self-biting behavior, while simultaneously increasing locomotor activity. When animals received a fixed dose of MK-801 with increasing doses of pemoline, a competitive relationship emerged such that high-dose pemoline surmounted the antagonistic effect of MK-801. In contrast to spiperone, delayed administration of MK-801 was ineffective in blocking the subsequent expression of self-biting behavior, suggesting that dizocilpine exerts its protective effect early in the cascade of events which eventually leads to self-biting behavior in this paradigm.

Psychiatric consultation in severe and profound mental retardation

OBJECTIVE

This study was designed to examine the relationship between reason for referral and subsequent DSM-III-R diagnosis in institutionalized individuals with severe to profound mental retardation. A heavy emphasis was placed on articulating how diagnostic criteria are applied in this population.

METHOD

The study population consisted of 251 patients consecutively referred for initial psychiatric consultation from a large series of institutionalized patients with predominately severe to profound mental retardation. On the basis of the chief complaint, subjects could be grouped into six overlapping categories: self-injury, aggression, hyperactivity, agitation, medical questions, and miscellaneous behaviors. Psychiatric diagnoses were made according to DSM-III-R criteria on the basis of simultaneous clinical examination, staff interview, and medical review. Relevant medical conditions were noted.

RESULTS

The authors demonstrate, as have others, that it is possible to make psychiatric diagnoses in this population and that psychiatric disorder is common. The most frequent diagnoses were impulse control disorders, anxiety disorders, and mood disorders. Comorbid medical conditions, particularly seizure disorders, are also common.

CONCLUSIONS

These results are consistent with the reported experience of others and underscore the importance of psychiatric involvement in the multidisciplinary assessment and treatment of individuals with retardation.

Low-dose naltrexone inhibits pemoline-induced self-biting behavior in prepubertal rats

ABSTRACT Pemoline-induced self-biting behavior has been compared to similar self-injurious behavior (SIB) that occurs in the context of some mental retardation syndromes. The opiate antagonist, naltrexone, has been used successfully in the treatment of SIB in individuals with autism or mental retardation. This is the first report of the effect of naltrexone in an animal model of self-biting behavior. Naltrexone (0.01 mg/kg s.c.) significantly reduced the severity of self-biting behavior, but higher doses (0.10-10 mg/kg s.c.) had no such effect. Consistent with these results in the rat, a review of the clinical use of naltrexone in SIB is also suggestive of a relative loss of efficacy at higher doses (apparent therapeutic window). Naltrexone has higher affinity for mu receptors than other opioid receptor subtypes. Thus, the effect of naltrexone in treating SIB appears to be due to (mu-receptor interactions, with the loss of effect at higher doses due to supervening kappa receptor binding. Speculatively, one may ask if dosage reduction would convert naltrexone nonresponders to responders by lowering kappa receptor-mediated effects. Given the co-localization of opioids and dopamine inputs in some neurons, opioid-dopamine system interactions may also be important in pemoline-induced self-biting behavior.