Pablo Davanzo

Decreased anterior cingulate myo-inositol/creatine spectroscopy resonance with lithium treatment in children with bipolar disorder.

This project was designed to compare differences in brain proton spectra between children and adolescents with bipolar disorder (BPD) and gender and age-matched normal controls, and to measure changes in myo-inositol levels following lithium therapy, utilizing in vivo proton magnetic resonance spectroscopy (1H MRS). A single voxel (2x2x2 cm3) was placed in brain anterior cingulate cortex for acquisition of the 1H spectra at baseline and after acute (∼7 days) lithium administration in 11 children (mean age 11.4 years) diagnosed with BPD, and in 11 normal controls. Acute lithium treatment was associated with a significant reduction in the myo-inositol/creatine ratio. This decrement was also significant in lithium-responders when analyzed separate from non-responders. Compared to normal controls, BPD subjects showed a trend towards a higher myo-inositol/creatine during the manic phase. These preliminary data provide evidence that a significant reduction in anterior cingulate myo-inositol magnetic resonance may occur after lithium treatment, especially among responders. Follow-up studies involving a larger sample may allow us to confirm whether changes in myo-inositol associated with acute lithium therapy persist in long-term clinical response of patients with and without lithium compliance.

Double-blind, placebo-controlled study of amantadine hydrochloride in the treatment of children with autistic disorder

OBJECTIVE To test the hypothesis that amantadine hydrochloride is a safe and effective treatment for behavioral disturbances--for example, hyperactivity and irritability--in children with autism. METHOD Thirty-nine subjects (intent to treat; 5-19 years old; IQ > 35) had autism diagnosed according to DSM-IV and ICD-10 criteria using the Autism Diagnostic Interview-Revised and the Autism Diagnostic Observation Schedule-Generic. The Aberrant Behavior Checklist-Community Version (ABC-CV) and Clinical Global Impressions (CGI) scale were used as outcome variables. After a 1-week, single-blind placebo run-in, patients received a single daily dose of amantadine (2.5 mg/kg per day) or placebo for the next week, and then bid dosing (5.0 mg/kg per day) for the subsequent 3 weeks. RESULTS When assessed on the basis of parent-rated ABC-CV ratings of irritability and hyperactivity, the mean placebo response rate was 37% versus amantadine at 47% (not significant). However, in the amantadine-treated group there were statistically significant improvements in absolute changes in clinician-rated ABC-CVs for hyperactivity (amantadine -6.4 versus placebo -2.1; p = .046) and inappropriate speech (-1.9 versus 0.4; p = .008). CGI scale ratings were higher in the amantadine group: 53% improved versus 25% (p = .076). Amantadine was well tolerated. CONCLUSIONS Parents did not report statistically significant behavioral change with amantadine. However, clinician-rated improvements in behavioral ratings following treatment with amantadine suggest that further studies with this or other drugs acting on the glutamatergic system are warranted. The design of these and similar drug trials in children with autistic disorder must take into account the possibility of a large placebo response.

Increased anterior cingulate/medial prefrontal cortical glutamate and creatine in bipolar depression

Proton magnetic resonance spectroscopy (1HMRS) is an in vivo brain imaging method that can be used to investigate psychotropic drug mechanism of action. This study evaluated baseline 1HMRS spectra of bipolar depressed patients and whether the level of cerebral metabolites changed after an open trial of lamotrigine, an anti-glutamatergic mood stabilizer. Twenty-three bipolar depressed and 12 control subjects underwent a MRS scan of the anterior cingulate/medial prefrontal cortex. The scan was performed on a GE whole-body 1.5 T MRI scanner using single-voxel PRESS (TE/TR=30/3000 ms, 3 × 3 × 3 cm3 and post-processed offline with LCModel. Baseline CSF-corrected absolute concentrations of glutamate+glutamine ([Glx]), glutamate ([Glu]), and creatine+phosphocreatine ([Cr]) were significantly higher in bipolar depressed subjects vs healthy controls. The non-melancholic subtype had significantly higher baseline [Glx] and [Glu] levels than the melancholic subtype. Remission with lamotrigine was associated with significantly lower post-treatment glutamine ([Gln]) in comparison to non-remission. These data suggest that non-melancholic bipolar depression is characterized by increased glutamate coupled with increased energy expenditure. Lamotrigine appears to reduce glutamine levels associated with treatment remission. Further study is encouraged to determine if these MR spectroscopic markers can delineate drug mechanism of action and subsequent treatment response.

Mental Retardation: A Review of the Past 10 Years. Part II

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.

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.

Mood stabilizers in hospitalized children with bipolar disorder: A retrospective review

A paucity of naturalistic data supported a rationale for the present retrospective review of clinical changes during hospitalization in 44 bipolar pre‐adolescents, treated with monotherapy lithium, carbamazepine (CBZ) or divalproex sodium (DVP). Daily staff progress notes and discharge summaries on each patient were read by four trained clinicians blind to treatment group, and rated according to the Clinical Global Impression Improvement (CGI‐I) scale. Consensus rating was measured by kappa reliability. Data were analyzed using a general linear model (sas mixed) analysis of variance (anova) with repeated measures. The medication groups did not differ in length of hospitalization, overall severity of illness at the time of admission, or comorbidity. Prior treatment was considered as a covariate. Each group approached serum therapeutic levels at day 7 of the medication period. The estimated mean CGI‐I scores for CBZ were systematically higher (i.e. worse) than those for lithium and DVP, which overlapped and crossed over time. The difference became increasingly apparent and was statistically significant by week 2 (P = 0.036). The present study was limited in that the sample sizes, particularly in the case of CBZ, were small, commensurate with the low prevalence of the disorder. Lack of structured interviews, as an independent assessment of diagnoses was an intrinsic limitation of the study. Although constrained by its retrospective nature, our findings suggest that by week 2 of hospitalization both lithium and DVP may be more efficacious than CBZ in bipolar pre‐adolescents. Any significant finding must be viewed as tentative and subject to confirmation in other studies.

The New Medical Model: Interdisciplinary Treatment and the Limits of Behaviorism:

The new medical model of special education for children with emotional or behavioral disorders posits that a significant number of children in this category may not only have psychiatric disorders that are treatable with psychopharmacologic medication but that special educators also have a responsibility to screen for such diagnoses when indicated. Gresham (2002) and Oswald (2002) have provided responses to this concept that represent opposite views. These are discussed in relation to (a) the role of psychiatric diagnosis in special education, (b) the relative efficacy of behavioral versus psychopharmacologic treatment, and (c) the nature of interdisciplinary care. Combined behavioral and psychopharmacologic intervention represents best practice in most cases. Resistance to this concept of the new medical model, however, seems to be based on evidence that is less than convincing.

Mood stabilizers in the treatment of juvenile bipolar disorder. Advances and controversies.

Controlled studies of mood stabilizer (mono and combination) therapy are needed in children and adolescents to develop safe and effective treatment strategies for a disorder that now has a cohort and that carries a high human and economic cost. Through the use of a variety of diagnostic instruments and novel outcome measures, we may continue to refine DSM categories into more sensitive and specific diagnostic constructs. In addition, identification of neurobiologic and genetic markers for early-onset BPD, ADHD, CD, and IED could provide powerful tools in the process of breaking down phenotypes and establishing biologic predictors of targeted pharmacologic interventions in the face of new drug developments.

Results of a SNP genome screen in a large Costa Rican pedigree segregating for severe bipolar disorder

We have ascertained in the Central Valley of Costa Rica a new kindred (CR201) segregating for severe bipolar disorder (BP‐I). The family was identified by tracing genealogical connections among eight persons initially independently ascertained for a genome wide association study of BP‐I. For the genome screen in CR201, we trimmed the family down to 168 persons (82 of whom are genotyped), containing 25 individuals with a best‐estimate diagnosis of BP‐I. A total of 4,690 SNP markers were genotyped. Analysis of the data was hampered by the size and complexity of the pedigree, which prohibited using exact multipoint methods on the entire kindred. Two‐point parametric linkage analysis, using a conservative model of transmission, produced a maximum LOD score of 2.78 on chromosome 6, and a total of 39 loci with LOD scores >1.0. Multipoint parametric and non‐parametric linkage analysis was performed separately on four sections of CR201, and interesting (nominal P‐value from either analysis <0.01), although not statistically significant, regions were highlighted on chromosomes 1, 2, 3, 12, 16, 19, and 22, in at least one section of the pedigree, or when considering all sections together. The difficulties of analyzing genome wide SNP data for complex disorders in large, potentially informative, kindreds are discussed.

A narrow and highly significant linkage signal for severe bipolar disorder in the chromosome 5q33 region in Latin American pedigrees.

We previously reported linkage of bipolar disorder to 5q33‐q34 in families from two closely related population isolates, the Central Valley of Costa Rica (CVCR) and Antioquia, Colombia (CO). Here we present follow up results from fine‐scale mapping in large CVCR and CO families segregating severe bipolar disorder, BP‐I, and in 343 population trios/duos from CVCR and CO. Employing densely spaced SNPs to fine map the prior linkage peak region increases linkage evidence and clarifies the position of the putative BP‐I locus. We performed two‐point linkage analysis with 1134 SNPs in an approximately 9 Mb region between markers D5S410 and D5S422. Combining pedigrees from CVCR and CO yields a LOD score of 4.9 at SNP rs10035961. Two other SNPs (rs7721142 and rs1422795) within the same 94 kb region also displayed LOD scores greater than 4. This linkage peak coincides with our prior microsatellite results and suggests a narrowed BP‐I susceptibility regions in these families. To investigate if the locus implicated in the familial form of BP‐I also contributes to disease risk in the population, we followed up the family results with association analysis in duo and trio samples, obtaining signals within 2 Mb of the peak linkage signal in the pedigrees; rs12523547 and rs267015 (P = 0.00004 and 0.00016, respectively) in the CO sample and rs244960 in the CVCR sample and the combined sample, with P = 0.00032 and 0.00016, respectively. It remains unclear whether these association results reflect the same locus contributing to BP susceptibility within the extended pedigrees.