Stimulant drug effects in developmental disorders and hyperactivity--toward a resolution of disparate findings

Methylphenidate for children and adolescents with autism spectrum disorder

BACKGROUND

Children with autistic spectrum disorder (ASD) frequently present with inattention, impulsivity and hyperactivity, which are the cardinal symptoms of attention deficit hyperactivity disorder (ADHD). The effectiveness of methylphenidate, a commonly used ADHD treatment, is therefore of interest in these children.

OBJECTIVES

To assess the effects of methylphenidate for symptoms of ADHD (inattention, impulsivity and hyperactivity) and ASD (impairments in social interaction and communication, and repetitive, restricted or stereotypical behaviours) in children and adolescents aged 6 to 18 years with ASD.

SEARCH METHODS

In November 2016, we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 11 other databases and two trials registers. We also checked reference lists and contacted study authors and pharmaceutical companies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that investigated the effect of methylphenidate versus placebo on the core symptoms of ASD or ADHD-like symptoms, or both, in children aged 6 to 18 years who were diagnosed with ASD or pervasive developmental disorder. The primary outcome was clinical efficacy, defined as an improvement in ADHD-like symptoms (inattention, impulsivity and hyperactivity) and in the core symptoms of ASD (impaired social interaction, impaired communication, and stereotypical behaviours), and overall ASD. Secondary outcomes examined were: rate of adverse events; caregiver well-being; need for institutionalisation, special schooling or therapy to achieve learning outcomes; and overall quality of life.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. We combined outcome measures that used different psychometric scales, where clinically appropriate. We used a coefficient of 0.6 to calculate standard deviations and adjust for the studies' cross-over design. We considered a standardised mean difference (SMD) of 0.52 as the minimum clinically relevant inter-treatment difference. We applied the GRADE rating for strength of evidence for each outcome.

MAIN RESULTS

The studies: we included four cross-over studies, with a total of 113 children aged 5 to 13 years, most of whom (83%) were boys. We included two studies with five-year-old children since we were unable to obtain the disaggregated data for those aged six years and above, and all other participants were in our target age range. All participants resided in the USA. The duration of treatment in the cross-over phase was one week for each dose of methylphenidate. Studies used a range of outcome scales, rated by parents, teachers or both; clinicians; or programme staff. We report parent-rated outcomes separately. Risk of bias: we considered three trials to be at high risk of bias due to selective reporting and all trials to be at unclear risk of bias for blinding of participants and assessors, due to the potential for recognising the side effects of methylphenidate. We judged all trials to be at low or unclear risk of bias for other items. Primary outcomes: the meta-analysis suggested that high-dose methylphenidate (0.43 mg/kg/dose to 0.60 mg/kg/dose) had a significant and clinically relevant benefit on hyperactivity, as rated by teachers (SMD -0.78, 95% confidence interval (CI) -1.13 to -0.43; 4 studies, 73 participants; P < 0.001; low-quality evidence) and parents (mean difference (MD) -6.61 points, 95% CI -12.19 to -1.03, rated on the hyperactivity subscale of the Aberrant Behviour Checklist, range 0 to 48; 2 studies, 71 participants; P = 0.02; low-quality evidence). Meta-analysis also showed a significant but not clinically relevant benefit on teacher-rated inattention (MD -2.72 points, 95% CI -5.37 to -0.06, rated on the inattention subscale of the Swanson, Nolan and Pelham, Fourth Version questionnaire, range 0 to 27; 2 studies, 51 participants; P = 0.04; low-quality evidence). There were inadequate data to conduct a meta-analysis on the symptom of impulsivity. There was no evidence that methylphenidate worsens the core symptoms of ASD or benefits social interaction (SMD -0.51, 95% CI -1.07 to 0.05; 3 studies, 63 participants; P = 0.07; very low-quality evidence), stereotypical behaviours (SMD -0.34, 95% CI -0.84 to 0.17; 3 studies, 69 participants; P = 0.19; low-quality evidence), or overall ASD (SMD -0.53, 95% CI -1.26 to 0.19; 2 studies, 36 participants; P = 0.15; low-quality evidence), as rated by teachers. There were inadequate data to conduct a meta-analysis on the symptom of impaired communication.

SECONDARY OUTCOMES

no data were available for the secondary outcomes of caregiver well-being; need for institutionalisation, special schooling options or therapy to achieve learning outcomes; or overall quality of life. No trials reported serious adverse events. The only adverse effect that was significantly more likely with treatment was reduced appetite as rated by parents (risk ratio 8.28, 95% CI 2.57 to 26.73; 2 studies, 74 participants; P < 0.001; very low-quality evidence). Subgroup analysis by dose did not identify any significant differences in effect on our primary outcomes between low-, medium- or high-dose ranges.

AUTHORS' CONCLUSIONS

We found that short-term use of methylphenidate might improve symptoms of hyperactivity and possibly inattention in children with ASD who are tolerant of the medication, although the low quality of evidence means that we cannot be certain of the true magnitude of any effect. There was no evidence that methylphenidate has a negative impact on the core symptoms of ASD, or that it improves social interaction, stereotypical behaviours, or overall ASD. The evidence for adverse events is of very low quality because trials were short and excluded children intolerant of methylphenidate in the test-dose phase. Future RCTs should consider extending the duration of treatment and follow-up. The minimum clinically important difference also needs to be confirmed in children with ASD using outcome scales validated for this population.

Effects of extended release methylphenidate treatment on ratings of attention-deficit/hyperactivity disorder (ADHD) and associated behavior in children with autism spectrum disorders and ADHD symptoms

OBJECTIVE

The purpose of this study was to examine the behavioral effects of four doses of psychostimulant medication, combining extended-release methylphenidate (MPH) in the morning with immediate-release MPH in the afternoon.

METHOD

The sample comprised 24 children (19 boys; 5 girls) who met American Psychiatric Association, Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV-TR) criteria for an autism spectrum disorder (ASD) on the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS), and had significant symptoms of attention-deficit/hyperactivity disorder (ADHD). This sample consisted of elementary school-age, community-based children (mean chronological age=8.8 years, SD=1.7; mean intelligence quotient [IQ]=85; SD=16.8). Effects of four dose levels of MPH on parent and teacher behavioral ratings were investigated using a within-subject, crossover, placebo-controlled design.

RESULTS

MPH treatment was associated with significant declines in hyperactive and impulsive behavior at both home and school. Parents noted significant declines in inattentive and oppositional behavior, and improvements in social skills. No exacerbation of stereotypies was noted, and side effects were similar to those seen in typically developing children with ADHD. Dose response was primarily linear in the dose range studied.

CONCLUSIONS

The results of this study suggest that MPH formulations are efficacious and well-tolerated for children with ASD and significant ADHD symptoms.

Prevalence and correlates of psychotropic medication use in adolescents with an autism spectrum disorder with and without caregiver-reported attention-deficit/hyperactivity disorder

BACKGROUND

Many youths with an autism spectrum disorder (ASD) benefit from psychotropic medication treatment of co-morbid symptom patterns consistent with attention-deficit/hyperactivity disorder (ADHD). The lack of clear indications and algorithms to direct clinical practice has led to a very poor understanding of overall medication use for these youths. The present study examined the prevalence of psychotropic medication use compared across individuals with an ASD without a caregiver-reported ADHD diagnosis (ASD-only), ADHD without ASD (ADHD-only), and an ASD with co-morbid ADHD (ASD+ADHD). Correlates of medication use were also examined.

METHODS

Data on psychotropic medication from the first wave of the National Longitudinal Transition Study 2, a nationally representative study of adolescents ages 13-17 in special education, were used to compare the prevalence of medication use across the three groups, overall and by class. Separate logistic regression models were constructed for each group to examine the correlates of psychotropic medication use. Poisson regression models were used to examine correlates of the number of medications.

RESULTS

Youths with ASD+ADHD had the highest rates of use (58.2%), followed by youths with ADHD-only (49.0%) and youths with ASD-only (34.3%). Youths with an ASD, both ASD-only and ASD+ADHD, used medications across a variety of medication classes, whereas stimulants were dominant among youths with ADHD-only. African American youths with ASD-only and with ASD+ADHD were less likely to receive medication than white youths, whereas race was not associated with medication use in the ADHD-only group.

CONCLUSIONS

Clearer practice parameters for ADHD have likely contributed to more consistency in treatment, whereas treatment for ASD reflects a trial and error approach based on associated symptom patterns. Additional studies examining the treatment of core and associated ASD symptoms are needed to guide pharmacologic treatment of these youths. Interventions targeting African American youths with ASD and the physicians who serve them are also warranted.

Recent advances in the pharmacotherapy of autism

This review examines the most recent evidence for the pharmacologic management of severe maladaptive behaviors often observed in patients with autistic disorder. Although a multimodal approach is imperative in the management of autism, medications are frequently required for the individual to benefit from behavioral and educational interventions. Several classes of medications appear helpful in diminishing specific target symptoms and include the atypical antipsychotics, selective serotonin reuptake inhibitors, mirtazapine, mood stabilizers and alpha(2)-adrenergic agonists. Controlled research and longitudinal studies are needed to expand the knowledge base of these compounds as well as other medications under investigation. It is anticipated that future research regarding neuroimmunology, as well as the cholinergic and glutamatergic neurotransmitter systems, will contribute to our understanding of the pathophysiology of autistic disorder.

Pretreatment with l-histidine produces a shift from methamphetamine-induced stereotypical biting to persistent locomotion in mice

The administration of methamphetamine (METH; 10mg/kg, i.p.) to male ICR mice induced bizarre behaviors including persistent locomotion and stereotypical behaviors, which were classified into four categories: stereotypical head-bobbing, circling, sniffing, and biting. Pretreatment with l-histidine (750 mg/kg, i.p.) significantly decreased the stereotypical biting induced by METH and significantly increased persistent locomotion. This effect of l-histidine on behavior was completely abolished by simultaneous administration of pyrilamine or ketotifen (brain-penetrating histamine H(1) receptor antagonists; 10mg/kg each, i.p.), but not by the administration of fexofenadine (a non-sedating histamine H(1) receptor antagonist that does not cross the blood-brain barrier; 20mg/kg), zolantidine (a brain-penetrating histamine H(2) receptor antagonist; 10mg/kg), thioperamide, or clobenpropit (brain-penetrating histamine H(3) receptor antagonists; 10mg/kg each). The histamine content of the hypothalamus was significantly increased by l-histidine treatment. These data suggest that l-histidine modifies the effects of METH through central histamine H(1) receptors.

Sigma1 receptor antagonists determine the behavioral pattern of the methamphetamine-induced stereotypy in mice

OBJECTIVE

The effects of sigma receptor antagonists on methamphetamine (METH)-induced stereotypy have not been examined. We examined the effects of sigma antagonists on METH-induced stereotypy in mice.

RESULTS

The administration of METH (10 mg/kg) to male ddY mice induced stereotyped behavior consisting of biting (90.1%), sniffing (4.2%), head bobbing (4.1%), and circling (1.7%) during an observation period of 1 h. Pretreatment of the mice with BMY 14802 (alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazinebutanol; 1, 5, and 10 mg/kg), a non-specific sigma receptor antagonist, significantly increased METH-induced sniffing (19.2%, 30.5%, and 43.8% of total stereotypical behavior) but decreased biting (76.6%, 66.9%, and 49.3% of total stereotypical behavior) in a dose-dependent manner. This response was completely abolished by (+)-SKF 10,047 ([2S-(2alpha,6alpha,11R)]-1,2,3,4,5,6-hexahydro-6,11-dimethyl-3-(2-propenyl)-2,6-methano-3-benzazocin-8-ol; 4 and 10 mg/kg), a putative sigma(1) receptor agonist, and partially by PB 28 (1-cyclohexyl-4-[3-(1,2,3,4-tetrahydro-5-methoxy-1-naphthalen-1-yl)-n-propyl]piperazine; 1 and 10 mg/kg), a putative sigma(2) receptor agonist. The BMY 14802 action on METH-induced stereotypy was mimicked by BD 1047 (N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(dimethylamino)ethylamine; 10 mg/kg), a putative sigma(1) receptor antagonist, but not by SM-21 ((+/-)-tropanyl 2-(4-chlorophenoxy)butanoate; 1 mg/kg), a putative sigma(2) receptor antagonist. The BD 1047 effect on METH-induced stereotypy was also abolished completely by (+)-SKF 10,047 and partially by PB 28. The overall frequency of METH-induced stereotypical behavior was unchanged with these sigma receptor ligands, despite the alteration in particular behavioral patterns. The BMY 14802 action on METH-induced stereotypy was unaffected by pretreatment with centrally acting histamine H(1) receptor antagonists (pyrilamine or ketotifen, 10 mg/kg), suggesting that these effects are independent of histamine H(1) receptor signaling systems.

CONCLUSION

In summary, modulation of central sigma(1) receptors alters the pattern of METH-induced stereotypy, producing a shift from stereotypical biting to stereotypical sniffing, without affecting the overall frequency of stereotypical behavior.

Positive effects of methylphenidate on inattention and hyperactivity in pervasive developmental disorders: an analysis of secondary measures

BACKGROUND

Methylphenidate has been shown elsewhere to improve hyperactivity in about half of treated children who have pervasive developmental disorders (PDD) and significant hyperactive-inattentive symptoms. We present secondary analyses to better define the scope of effects of methylphenidate on symptoms that define attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD), as well as the core autistic symptom domain of repetitive behavior.

METHODS

Sixty-six children (mean age 7.5 y) with autistic disorder, Asperger's disorder, and PDD not otherwise specified, were randomized to varying sequences of placebo and three different doses of methylphenidate during a 4-week blinded, crossover study. Methylphenidate doses used approximated .125, .25, and .5 mg/kg per dose, twice daily, with an additional half-dose in the late afternoon. Outcome measures included the Swanson, Nolan, and Pelham Questionnaire revised for DSM-IV (ADHD and ODD scales) and the Children's Yale-Brown Obsessive Compulsive Scales for PDD.

RESULTS

Methylphenidate was associated with significant improvement that was most evident at the .25- and .5-mg/kg doses. Hyperactivity and impulsivity improved more than inattention. There were not significant effects on ODD or stereotyped and repetitive behavior.

CONCLUSIONS

Convergent evidence from different assessments and raters confirms methylphenidate's efficacy in relieving ADHD symptoms in some children with PDD. Optimal dose analyses suggested significant interindividual variability in dose response.

Atomoxetine for hyperactivity in autism spectrum disorders: placebo-controlled crossover pilot trial

OBJECTIVE

To explore placebo-controlled efficacy and safety of atomoxetine (ATX) for attention-deficit/hyperactivity disorder (ADHD) symptoms in children with autism spectrum disorders (ASD).

METHOD

Children ages 5 to 15 with ASD and prominent ADHD symptoms were randomly assigned to order in a crossover of clinically titrated ATX and placebo, 6 weeks each, separated by 1-week washout. Slopes for each condition were compared by paired t test.

RESULTS

In 2004-2005, 12 boys and 4 girls (7 with autistic disorder, 1 Asperger's, 8 pervasive developmental disorder not otherwise specified) all completed at least 3 weeks of each condition. On the primary outcome, the Hyperactivity subscale of the Aberrant Behavior Checklist, ATX was superior to placebo (p =.043, effect size d = 0.90). It was also superior on a 0 to 3 rating of nine DSM-IV ADHD hyperactive/impulsive symptoms (p =.005, d = 1.27), but missed significance on nine inattentive symptoms (p =.053, d= 0.89). Nine subjects responded to ATX, four to placebo (25% improvement on the Hyperactivity subscale plus Clinical Global Impressions-Improvement of 1-2. One was rehospitalized for recurrent violence on ATX. Adverse events were otherwise tolerable, with no tendency to stereotypy.

CONCLUSIONS

ATX appears safe and effective for treating hyperactivity in some children with autism spectrum disorders. The effect appears as large as in a multisite methylphenidate trial in the same population, with fewer intolerable side effects. Further study in autism spectrum disorders is indicated.

Medication patterns in patients with autism: temporal, regional, and demographic influences

To date, there have been relatively few surveys of psychotropic medicine use in individuals with autism. Data were analyzed from three statewide surveys that employed the same questionnaire and survey methodology. The first was done in the Autism Society of North Carolina in 1992-1993 (NC-1, n = 838; Aman et al. 1995); the second was done in the Autism Society of Ohio in 1999 (Ohio, n = 417; Aman et al. 2003), and the third was done again in the Autism Society of North Carolina in 2001 (NC-2, n = 1538; Langworthy-Lam et al. 2002). Response rates ranged from 48%-56%. Longitudinal trends were examined by comparing the NC-1 and NC-2 data, and regional effects were assessed by comparing the NC-2 and Ohio data. There was a very large increase in antidepressant utilization from 1993 to 2001, with significant increases also occurring for antipsychotics, psychostimulants, and alpha-agonists and beta-blockers. Among youths with autism, the use of any psychotropic increased from 30.5% in NC-1 to 45.2% in NC-2. Psychotropic medication patterns were remarkably consistent across North Carolina and Ohio, except that significantly more autism supplements were used in Ohio. We also examined subject and demographic variables across studies and found several robust correlates of psychotropic medication use. Greater age and handicap, and more restrictive placements, were associated with the use of several drug classes. Knowledge of these patterns may help families and medical planners anticipate future needs.

A naturalistic retrospective analysis of psychostimulants in pervasive developmental disorders

OBJECTIVE

We set out to examine the effectiveness and tolerability of psychostimulants in children and adolescents with pervasive developmental disorders (PDDs).

METHODS

Medical records of all patients with PDDs treated with a stimulant were retrospectively reviewed. Demographics, stimulant type, drug dosage, trial duration, and adverse effects were recorded. Global improvement, focused on symptoms of hyperactivity and inattention, was measured by the Clinical Global Impressions-Improvement scale, with positive response defined by a rating of much improved or very much improved.

RESULTS

Of 195 patients (174 males, 21 females; mean age +/- SD = 7.26 +/- 3.45 years, range 2-19 years), 61 had more than one trial, resulting in a total of 274 separate stimulant trials. It was discovered that 24.6%, 23.2%, and 11.1% of patients with a history of one, two, or three stimulant trials, respectively, responded to their first stimulant trial. Among first trial nonresponders, 6 (14.0%) of 43 patients responded to a second trial. Of those who did not respond to their first or second stimulant trial, 2 (14.3%) of 14 patients responded to a third trial. Patients with Asperger's disorder, in contrast to those with autistic disorder or PDD not otherwise specified, were significantly more likely to respond to a stimulant trial (p < 0.01). Use of concomitant medication (p < 0.007) positively affected response, whereas no association was found between stimulant type and IQ and response. Adverse effects, including agitation, dysphoria, and irritability, often occurred (154 [57.5%] of 268 trials, with 6 missing values).

CONCLUSIONS

Overall, stimulants appeared ineffective and poorly tolerated for the majority of patients with PDDs. Response may differ with PDD subtype. Controlled studies are needed to further evaluate these preliminary findings in a systematic manner.

Methylphenidate treatment in children with borderline IQ and mental retardation: analysis of three aggregated studies

OBJECTIVE

To determine response of low-IQ children with attention deficit hyperactivity disorder (ADHD) symptoms to methylphenidate (MPH).

METHODS

An aggregated analysis was conducted in 90 children with low IQ who received the same dose regimen of MPH in three independent, placebo-controlled studies. Active drug and placebo were given from 2 to 4 weeks each. Outcome measures included teacher and parent ratings on standardized behavior scales (mean n = 84), performance on computer-controlled cognitive-motor tests (n = 62), and measures of cardiovascular response (n = 85).

RESULTS

Both teachers and parents rated the children consistently as being improved on subscales assessing attention, overactivity, and conduct problems. Some 44% of the subjects showed at least a 30% reduction compared with placebo on teacher ratings. MPH improved accuracy on several cognitive tests, response speed was increased on some, and seat activity declined for one of three tests; heart rate was mildly increased (3.9 beats/minute) with MPH. Analyses of IQ and mental age as moderator variables suggested that lower functional level (especially lower IQ) may be associated with a less favorable response to MPH.

CONCLUSIONS

Children with low IQ and ADHD clearly respond to MPH, but their rate of beneficial response appears to be well under that of normal-IQ children and more varied. Different attentional mechanisms may moderate response to psychostimulants.

Pharmacotherapy for hyperactivity in children with autism and other pervasive developmental disorders

We reviewed pharmacological treatments used in children with autism and PDD-NOS who present with hyperactive symptoms. Some 41 studies were identified from the following drug categories: antipsychotics (n = 13), serotonin reuptake inhibitors (n = 3), antianxiety drugs (n = 4), psychostimulants (n = 10), alpha adrenergic agonists (n = 2), opiate blockers (n = 7), and other drugs (n = 2). Empirical evidence for significant reductions in hyperactive symptoms was strongest for the antipsychotics, psychostimulants, and naltrexone. Most studies have focused on the reduction of overactivity, and more emphasis needs to be placed on distractibility and attentional variables. A theoretical model was proposed in which participants' attentional performance may be used to predict clinical response to psychostimulants. More carefully controlled and comprehensive studies of hyperactivity are badly needed in these children.

Psychopharmacology in autism

Autism is a neurobiological disorder. The core clinical features of autism include impairment in social interaction, impairments in verbal and nonverbal communication, and restricted, repetitive, and stereotyped patterns of behavior, interests, and activities. Autism often has coexisting neuropsychiatric disorders, including seizure disorders, attention deficit hyperactivity disorder, affective disorders, anxiety disorder, obsessive-compulsive disorder, and Tourette disorder. No etiology-based treatment modality has been developed to cure individuals with autism. However, comprehensive intervention, including parental counseling, behavior modification, special education in a highly structured environment, sensory integration training, speech therapy, social skill training, and medication, has demonstrated significant treatment effects in many individuals with autism. Findings from preliminary studies of major neurotransmitters and other neurochemical agents strongly suggest that neurochemical factors play a major role in autism. The findings also provide the rationale for psychopharmacotherapy in individuals with autism. This article reviews studies of neurochemical systems and related psychopharmacological research in autism and related neuropsychiatric disorders. Clinical indications for pharmacotherapy are described, and uses of various medications are suggested. This article also discusses new avenues of investigation that may lead to the development of more effective medication treatments in persons with autism.

Separate and combined effects of methylphenidate and a behavioral intervention on disruptive behavior in children with mental retardation

We investigated the separate and combined effects of a behavioral intervention and methylphenidate (Ritalin) on disruptive behavior and task engagement in 3 children with severe to profound mental retardation. The behavioral intervention involved differential reinforcement of appropriate behavior and guided compliance. All 3 children demonstrated decreased disruptive behavior and improved task engagement in response to the response to the behavioral intervention. Two of the 3 children demonstrated similar improvement in response to methylphenidate. Although both interventions were highly effective for these 2 participants, the relative efficacy of the interventions varied between the 2 children. There was no evidence of an additive or synergistic effect of the two interventions, but the high efficacy of each intervention alone limited our ability to detect such effects.

Psychotropic and anticonvulsant drugs in subjects with autism: prevalence and patterns of use

OBJECTIVE

To survey the prevalence and patterns of psychotropic and anticonvulsant medication and vitamin treatments in patients with autism.

METHOD

Caregivers of 1,595 index cases were sent survey questionnaires by mail, and repeat questionnaires were sent twice if no reply was received.

RESULTS

A total of 838 care providers (53%) responded to the survey. In all, 33.8% of the sample was taking some psychotropic drug or vitamin for autism or associated behavioral/psychiatric problems. A total of 19.2% reported having epilepsy, but only 13.2% were taking anticonvulsant drugs. More than 50% of the sample was taking some psychotropic, antiepileptic, vitamin, or "medical" agent. Of the agents taken, care providers were most satisfied with anticonvulsants, antidepressants, and stimulants. The use of each drug group was analyzed with respect to subject and demographic variables to evaluate medication patterns within this population.

CONCLUSION

As in the often related clinical population of mental retardation, psychotropic medication appears to be heavily used in patients with autism.

Methylphenidate and ADHD: influence of age, IQ and neurodevelopmental status

Sixty-nine children with attention deficit hyperactivity disorder (ADHD) underwent blind methylphenidate trials. 36 had ADHD alone (with or without a learning disability) and 33 had additional neurodevelopmental disorders. Of the children with ADHD alone, 88 per cent improved significantly on methylphenidate. This did not differ significantly from the 69 per cent response rate for children with ADHD and other neurodevelopmental disorders. The results confirm and add to the research literature indicating that ADHD children who are of preschool age and/or who have co-existing neurological disorders may benefit from methylphenidate.

Attention deficit-hyperactivity disorder among mentally retarded children

Teachers completed the Connors' Teacher Rating Scale (CTRS-39) on 100 boys assigned to one of four groups based on an IQ screen and scores on a DSM-III-R checklist of the symptoms for Attention Deficit-Hyperactivity Disorder (AD-HD). The groups included children rated high on AD-HD, mentally retarded children, mentally retarded children rated high on AD-HD, and a normal control group. Using the CTRS-39, there were no significant differences between the normal IQ AD-HD group and the mentally retarded AD-HD group on all but one of the factors. Mentally retarded children in general were found to be more anxious than their normal peers, whereas normal IQ AD-HD children were rated higher than the other groups on the Asocial factor. Implications of these data and future directions are discussed.

Fenfluramine and methylphenidate in children with mental retardation and attention deficit hyperactivity disorder: laboratory effects

Twenty-eight children took part in a double-blind, placebo-controlled, crossover study of fenfluramine and methylphenidate. Fenfluramine dosage was gradually increased to a standardized dose of 1.5 mg/kg per day, whereas methylphenidate was given in doses of 0.4 mg/kg per day. The children were assessed on laboratory tests of selective and sustained attention, visual matching, and color matching, during which seat activity was monitored automatically. Results showed fenfluramine to be superior to placebo on the memory task, whereas methylphenidate reduced commission errors on a continuous performance test. Methylphenidate caused shorter response times, and fenfluramine caused increases, on two of the tests. Examiner behavior ratings indicated significant improvements with both drugs on the domains of attention, activity level, and mood. These findings, together with those from a companion clinical study, suggest that the drugs may have contrasting mechanisms of action, but both appear to have useful clinical effects in these children.

Fenfluramine and methylphenidate in children with mental retardation and ADHD: clinical and side effects

Each of 28 nonautistic children with attention-deficit hyperactivity disorder and mental retardation received placebo, methylphenidate (0.4 mg/kg/day), and fenfluramine (gradually increased to 1.5 mg/kg/day) for 4 weeks each in a double-blind, crossover design. Teacher ratings indicated significant improvements with both active drugs on subscales designated as Conduct Problem, Hyperactivity, and Irritability, but methylphenidate alone produced improvements on an Inattention subscale. Parent ratings indicated significant improvements with both drugs on subscales labeled Hyperactivity, Motor Excess, and Conduct Problem. Fenfluramine alone caused improved parent ratings on Irritability and Inappropriate Speech, and on Conners' Abbreviated Symptom Questionnaire. Unlike a previous study, subgroup analyses failed to show a significantly better clinical response to methylphenidate for subjects with higher mental ages, although children with higher IQs responded better than those with IQs less than 45. The active drugs had contrasting effects on heart rate and blood pressure. Fenfluramine caused significant weight reductions relative to both placebo and methylphenidate. These findings suggest that both methylphenidate and fenfluramine have useful, but somewhat different, clinical effects in certain children with attention-deficit hyperactivity disorder and mental retardation.

Current developments in the understanding of mental retardation. Part II: Psychopathology

During recent years there has been greater recognition of the impressive degree of psychiatric disturbance that affects those with mental retardation. An increasing number of systematic studies are focusing on the prevalence, risk factors, and clinical characteristics of psychiatric disturbance within this population. In addition, traditional neuropsychiatric assessment and treatment approaches are being evaluated, and new approaches are being developed. Such efforts will undoubtedly improve the ability to effectively diagnose and treat mentally retarded individuals suffering from psychiatric disorders. This paper is the second of two reviews that explore several recent developments in biological, phenomenological, and psychopathological aspects of mental retardation.

Prediction of clinical response in children taking methylphenidate

Twenty-six children having Attention Deficit Hyperactivity Disorder were tested before and after treatment with methylphenidate. In addition to standardized parent and teacher rating scales, each child was assessed on a variety of psychomotor tests with an emphasis on attentional constructs. Relatively few of the performance tests, administered prior to medication, predicted clinical response to medication. However, chronological age and performance on a memory distraction task and on the Graduated Holes Task (Kløve, 1963) were moderately correlated with clinical outcome. Using stepwise multiple regression analyses to predict outcome, age and the psychomotor tasks predicted about 50% of outcome variance. There was virtually no relationship between clinical change and change on the performance tests. Findings are discussed with respect to results from previous prediction studies, theoretical models of drug response, and clinical management.

Hyperactivity and the fragile X syndrome

Workers who have claimed an association between Fragile X [fra(x)] Syndrome and Hyperactivity and aggressive behavior have done so despite the lack of controlled studies using standard diagnostic criteria. Accordingly, we provided a controlled test of the hypothesis that individuals with the fra(x) Syndrome are more hyperactive and have more symptoms of aggression than other mentally retarded individuals. The test formed part of a study to assess autistic behavior in fra(x) individuals. A sample of fra(x) individuals was obtained from the register of a clinical genetics unit and individually matched for age, sex, and IQ with mentally retarded individuals selected from assessment centres. Forty-five pairs of fra(x) cases and control individuals were compared on criteria which reflected DSM-III concepts of hyperactivity and on criteria reflecting aggressive behavior. The comparison failed to find a higher prevalence of these symptoms in the fra(x) group. An analysis of the study's statistical power suggested that it is unlikely that the investigation failed to detect a large to medium difference between fra(x) individuals and control individuals in the symptoms investigated.

Clinical effects of methylphenidate and thioridazine in intellectually subaverage children

Thirty children with subaverage IQs and psychiatric diagnoses of attention deficit disorder and/or or conduct disorder took part in a double-blind study of placebo, methylphenidate, and thioridazine, which were given for 3 weeks each. The results showed a consistent and highly significant effect of methylphenidate in reducing teacher ratings of problem behavior. Parent ratings showed no behavioral effects for the group as a whole. An attentional model of stimulant drug response was used to divide subjects according to a cognitive maturity domain presumed to reflect selective attention. When divided according to breadth of attention, mental age, and IQ level, higher functioning subjects were found to show a generally favorable response to methylphenidate on both teacher and parent rating scales, whereas children of low functional level typically showed an adverse or indifferent response. The present data suggest that mental age and IQ may be important determinants of drug response; below a given level, there was a greatly reduced likelihood of responding positively. Clinical response to thioridazine was substantially less than the response to methylphenidate, with significant improvements confined to conduct and hyperactivity problems on teacher ratings.

Treatment of ADDH in mentally retarded children: a preliminary study

The use of CNS stimulant medication for the treatment of attention deficit disorder with hyperactivity (ADDH) in subnormal intelligence children remains controversial, and the majority of the literature does not support the use of CNS stimulants in these children, although the choice of dependent variables and research designs may have contributed to this outcome. A single case research design was used to assess the effectiveness of CNS stimulant medication (methylphenidate and dextroamphetamine) in three subnormal intelligence children with ADDH, using excessive movement and on-task behaviors as dependent variables. The results and implications for future research are discussed.

Review of fenfluramine in the treatment of the developmental disabilities

Fenfluramine, a serotonin reducing agent, has been the subject of intense research effort in recent years. A variety of biochemical studies summarized suggest that some autistic children and many nonautistic severely retarded individuals have elevated blood serotonin concentrations. The research on fenfluramine's clinical efficacy is thoroughly reviewed from a methodological perspective. All studies assessing the drug's effects on blood serotonin have observed reductions in whole blood serotonin to about 50% of baseline concentrations. Although there were early reports of drug enhancement of IQ, there is no good evidence that this is the case. However, there are data to suggest that fenfluramine may enhance social relatedness, reduce stereotypic behavior, lessen overactivity, and improve attention span in some autistic children, although these results do not appear consistently across studies. The animal literature on the neurotoxicity of fenfluramine is reviewed, and a number of limitations in this research are identified that raise questions about its relevance to the pharmacotherapy of children.

Fragile X syndrome

Fragile X syndrome is one of the most intriguing genetic conditions now being studied. As the most common inherited form of mental retardation, it has an incidence of approximately 1 in 1000 male infants and boys. Because the cytogenetic diagnosis has only recently been available, many affected boys and female carriers have not yet been identified. This article reviews the characteristic, clinical features of fragile X syndrome and discusses treatment and intervention.

A controlled trial of stimulant medication in children with the fragile X syndrome

Attentional deficits and hyperactivity frequently are major problems for fra(X) boys. This study evaluated the effectiveness of 2 stimulant medications, methylphenidate and dextroamphetamine compared to placebo in 15 children (13 males, 2 females) with the fra(X) syndrome. A double-blind crossover design was used with outcome measures which included parent and teacher behavior checklists, a controlled observation period, continuous performance tasks and an actometer measure of movement. When the children were treated with methylphenidate only, improvement was seen in socialization skills and attention span according to teacher checklists. Ten children were clinically considered responders and treatment was continued after the study was completed.

Methylphenidate affects strategic choice behavior in normal adult humans

The time course of serum concentration and performance on a concurrent probability matching task were evaluated in normal adults receiving 0.15 or 0.3 mg/kg of methylphenidate. The behavioral task, an arcade-like problem-solving game, revealed that drug-treated subjects improved their performance upon repeated testings during pharmacokinetic evaluation at a lower rate than did non-treated controls over the same time span. However, drug-treated subjects failed to adopt the adaptive problem-solving strategies selected by controls.

Clinical management of children with hyperactivity. A shift in diagnostic and therapeutic emphasis

Children who have attention deficit disorder with (or without) hyperactivity are handicapped by their inability to concentrate and control their impulsivity, especially while in school. Specific performance disabilities prevent them from demonstrating, especially through written schoolwork, what they have learned. Parents and teachers are likely to mistake these children's symptoms for willful misbehavior or lack of motivation, which leads to misunderstandings and even mistreatment. The critical issue in the management of a child with hyperactivity is to effectively treat the key problems of inattention and impulsivity rather than the hyperactivity per se. A nonintensive long-term approach combining stimulant therapy and a cooperative liaison among the physician, child, family, and teachers is recommended.

The treatment of autistic children

The goals of treatment need to be decided on the basis of knowledge on the nature of autism. As with any developmental disorder, the first goal must be to foster normal development; with autistic children this involves a focus on intellectual, language and social development. The further goals include: the reduction of rigidity/stereotypy; the elimination of non-specific maladaptive behaviours; and alleviation of family distress. Research findings are used to translate these goals into a practical overall therapeutic programme with three main elements: a full diagnostic appraisal, special educational provision and a home-based programme for the family. Finally, the research findings are drawn together to derive inferences on the lessons to be learned and the questions that remain to be answered.

Medication regimen: a subject characteristic rarely reported in behavior modification studies

The present study determined whether articles describing attempts to alter behavior in mentally retarded participants through nonpharmacological interventions typically specify whether participants received medication during the experiments. From 1978 through 1982, the vast majority of such articles published in the American Journal of Mental Deficiency, Behavior Modification, Behavior Therapy, the Journal of Applied Behavior Analysis, and Mental Retardation failed to specify whether participants were receiving drugs. In addition, very few articles examined pharmacological interventions or attempted to address the interaction of drug and nondrug treatments.

Effects of methylphenidate in normal adults with reference to drug action in hyperactivity

Methylphenidate was administered to each of 12 adult volunteers in a double-blind, placebo-controlled, crossover study for purposes of comparison with previous studies in hyperactive children. Statistically significant changes occurred only on a minority of measures, but the results were generally in the direction of facilitated performance, reduced physical activity and increased emotional responsivity. As these results are similar to those in hyperactive and normal children, this appears to support the contention that stimulant drug effects in hyperactive children are not paradoxical or atypical.

Hyperactivity: nature of the syndrome and its natural history

The composition of hyperactivity as a syndrome is discussed from a historical perspective, and the principal events leading to the recent emphasis on attentional characteristics of hyperactive children are summarized. Some of the major challenges to the legitimacy of hyperactivity as a valid syndrome are set forth, and after critical examination of the most influential work, it is concluded that hyperactivity has not been disproved. This is followed by a survey of the large follow-up literature dealing with the natural history of children diagnosed as hyperactive. It is noted that the manifestations of the syndrome appear to change with age but there is little indication that problems simply remit with maturity. The evidence indicates that hyperactivity, as diagnosed in the past, is often a serious disorder with long-term and far-reaching consequences for the children and their families. Multivariate studies are also discussed, as they have important implications for differential outcome. Different symptoms such as aggression, overactivity, and learning disability appear to contain unique information about current and future status, and therefore it appears useful to retain these distinctions rather than view such children as part of an undifferentiated group. It is unknown whether the recent guidelines for diagnosing Attention Deficit Disorder with Hyperactivity will alter or refine the outlook for children so identified, but this is an active area of research at present.

Methylphenidate in severely retarded residents and the clinical significance of stereotypic behavior

An attempt was made to evaluate a model predicting stimulant drug response based on attentional characteristics of the participants. Twenty-eight severely and profoundly mentally retarded residents took part in a double blind, placebo controlled trial of methylphenidate (Ritalin). Methylphenidate was administered, for one week each, in a low dose of 0.3 mg/kg and a high dose of 0.6 mg/kg. The results failed to show any clinically relevant differences between placebo and active drug conditions with the exception that methylphenidate caused a significant reduction in food consumption. A variety of subject characteristics, including level of stereotypy, hyperactivity, and IQ were unrelated to drug effect. One positive finding, unrelated to drug effects, was that subdivision of the group by degree of stereotypy provided substantial clinical information about individual subjects.