•LPS plus interferon-γ upregulate CB2 receptors in microglia.•LPS plus interferon-γ upregulate CB1-CB2 receptor complexes in microglia.•ß amyloid and LPS plus interferon-γ lead to similar activation ...traits in microglia.•Activated microglia is identified in pups of an Alzheimer’s disease model.•Dyskinesia in Parkinson’s correlates with CB1-CB2 receptor complex upregulation.
Endocannabinoids are important regulators of neurotransmission and, acting on activated microglia, they are postulated as neuroprotective agents. Endocannabinoid action is mediated by CB1 and CB2 receptors, which may form heteromeric complexes (CB1-CB2Hets) with unknown function in microglia. We aimed at establishing the expression and signaling properties of cannabinoid receptors in resting and LPS/IFN-γ-activated microglia. In activated microglia mRNA transcripts increased (2 fold for CB1 and circa 20 fold for CB2), whereas receptor levels were similar for CB1 and markedly upregulated for CB2; CB1-CB2Hets were also upregulated. Unlike in resting cells, CB2 receptors became robustly coupled to Gi in activated cells, in which CB1-CB2Hets mediated a potentiation effect. Hence, resting cells were refractory while activated cells were highly responsive to cannabinoids. Interestingly, similar results were obtained in cultures treated with ß-amyloid (Aß1-42). Microglial activation markers were detected in the striatum of a Parkinson’s disease (PD) model and, remarkably, in primary microglia cultures from the hippocampus of mutant β-amyloid precursor protein (APPSw,Ind) mice, a transgenic Alzheimer’s disease (AD) model. Also of note was the similar cannabinoid receptor signaling found in primary cultures of microglia from APPSw,Ind and in cells from control animals activated using LPS plus IFN-γ. Expression of CB1-CB2Hets was increased in the striatum from rats rendered dyskinetic by chronic levodopa treatment. In summary, our results showed sensitivity of activated microglial cells to cannabinoids, increased CB1-CB2Het expression in activated microglia and in microglia from the hippocampus of an AD model, and a correlation between levodopa-induced dyskinesia and striatal microglial activation in a PD model. Cannabinoid receptors and the CB1-CB2 heteroreceptor complex in activated microglia have potential as targets in the treatment of neurodegenerative diseases.
Abstract Most adults with attention-deficit/hyperactivity disorder (ADHD) are not recognized and remain untreated, although a large fraction of these individuals are diagnosed and treated for other ...comorbid mental disorders, such as major depressive disorder (MDD). The fact that MDD is one of the most commonly occurring mental disorders with high comorbidity with adult ADHD raises the question whether such comorbidity is associated with differences in the clinical picture of ADHD. Three hundred and twenty adult ADHD outpatients were evaluated. Diagnoses followed DSM-IV criteria. Interviews to evaluate ADHD and oppositional defiant disorder (ODD) were performed based on the Portuguese version of K-SADS-E. Psychiatric comorbidities were investigated using SCID-IV and MINI. Regression models were applied to test MDD association with clinical and demographic outcomes. Subjects presenting ADHD and MDD had a higher frequency of generalized anxiety disorder and social phobia and a lower frequency of substance dependence, grade repetition and school suspensions, when compared to subjects with ADHD without MDD. Furthermore, adults presenting ADHD and MDD reported higher demand for psychotherapy and pharmacological treatment prior to enrollment in the study when compared to ADHD subjects free of MDD. However, contrary to what could be expected based on these data, the presence of MDD was not associated with an earlier ADHD diagnosis. These results point to the need for research and medical education into an earlier and more efficient ADHD diagnosis in patients who search for mental health care.
Results from pharmacogenetic investigations of methylphenidate (MPH) response in patients with ADHD are still inconsistent, especially among adults. This study investigates the role of genetic ...variants (SLC6A4, HTR1B, TPH2, DBH, DRD4, COMT, and SNAP25) in the response to MPH in a sample of 164 adults. Genes were chosen owing to previous evidence for an influence in ADHD susceptibility. No significant differences in allele or genotype frequencies between MPH responders and nonresponders were detected. In conclusion, our findings do not support an effect of these genes in the pharmacogenetics of MPH among adults with ADHD.
Abstract Objective The requirement in classificatory systems that some impairment from attention-deficit/hyperactivity disorder (ADHD) symptoms starts before 7 years of age (age of onset of ...impairment criteria – AOC) has been harshly criticized. Although there is evidence that late-onset ADHD is a valid diagnosis, little is known about the role of age of onset of impairment on the clinical profile of adult patients. Methods The diagnoses of 349 adults with ADHD followed DSM-IV criteria. ADHD and oppositional defiant disorder (ODD) were evaluated with the K-SADS-E, and other comorbidities with the SCID-IV and the MINI. Subjects were divided in early and late-onset groups (age of onset of impairment between 7 and 12 years old). The effect of age of onset over clinical and demographic characteristics was tested by regression models. Results Late-onset subjects were diagnosed later ( P = 0.04), had a lower frequency of problems with authority and discipline ( P = 0.004), and lower scores in SNAP-IV ( P < 0.001) and in Barkley’s scale for problems in areas of life activities ( P = 0.03). On the other hand, late-onset patients presented a higher prevalence of comorbid general anxiety disorder (GAD) ( P = 0.01). Both groups had a similar profile in the remaining comorbidities and sociodemographic characteristics. Conclusions This study provides initial evidence that adults with late-onset ADHD have less severity, lower frequency of externalizing symptoms and increased comorbidity with GAD, but similar profile in other comorbidities. In addition, the data suggest that late-onset patients have a higher probability of delayed diagnosis despite the significant impairment of their condition.
Abstract Polymorphisms in the CHRNA5-CHRNA3-CHRNB4 gene cluster (Chr15q25) have been robustly associated with nicotine dependence, including genome-wide studies, as well as with cognitive and ...neuropsychological measures. In addition, cognitive processes can be influenced by nicotine use through nicotinic acetylcholine receptors (nAChRs). Here, we evaluated the effect of polymorphisms in CHRNA5-CHRNA3-CHRNB4 gene cluster and their interaction with tobacco smoking status on cognition in patients with Attention Deficit/Hyperactivity Disorder (ADHD). Eight SNPs from the CHRNA5-CHRNA3-CHRNB4 gene cluster were evaluated on a clinical sample of 403 adults with ADHD. Cognitive performance was assessed using the Wechsler Adult Intelligence Scale-Revised (WAIS-R). Analyses of covariance were used to assess the influence of single markers and their interaction with smoking status in the Vocabulary and Block Design subtests of WAIS-R. Correction for multiple comparisons was applied. Lifetime smoking was associated to Vocabulary subtest. The TT genotypes of CHRNA5 SNPs rs588765 and rs514743 showed a trend towards association with, respectively, higher and lower scores on the Vocabulary subtest. There was a significant interaction between intergenic SNP rs8023462 and smoking on Vocabulary scores. Our results are consistent with an influence of variants in the CHRNA5 – CHRNA3 – CHRNB4 gene cluster on cognitive measures. The overall scenario suggests a pleiotropic role of Chr15q25 nicotinic gene cluster with complex influences in ADHD, tobacco smoking and cognitive performance, characteristics that can be partially interdependent and may share underlying genetic factors.
Abstract The consideration of age of onset of impairment as part of the ADHD diagnosis is controversial and has been a revisited issue with the emergence of the new classifications in Psychiatry. The ...aim of this study is to compare patients with early and late onset of ADHD impairment in terms of neuropsychological and personality characteristics. Adult patients with ADHD ( n = 415) were evaluated in the ADHD outpatient program at Hospital de Clínicas de Porto Alegre, Brazil. The diagnostic process for ADHD and comorbidities was based on DSM-IV criteria. The comparison between the two ages of onset groups (before 7; n = 209 or from 7 to 12 years; n = 206) was performed with ANOVA, followed by Stepwise forward regression analyses to restrict the number of comparisons and access the possible effect of multiple confounders. Patients with early onset ADHD present higher scores in novelty seeking in both analyses (respectively P = 0.016 and P = 0.002), but similar cognitive and attention features as compared with the late onset group. These data add to previous evidence that despite a more externalizing profile of early onset ADHD, the overall performance is similar reinforcing the need for awareness and inclusion of the late onset group in DSM-V diagnostic criteria.
Abstract Objective The prevalence of smoking is significantly increased among adults with Attention-Deficit/Hyperactivity Disorder (ADHD), and this association has a significant impact in both ...disorders, ascribed to either self-medication or behavioral disinhibition hypotheses. However, little is known about clinical variables associated with cigarette smoking among patients with ADHD. The present study evaluates comorbidity, demographic and personality profiles of patients with ADHD in relation to smoking status. Methods Patients ( n 422) were evaluated in the adult ADHD outpatient clinic of Hospital de Clínicas de Porto Alegre. Diagnoses were based on DSM-IV criteria and interviews were performed with Portuguese version of K-SADS-E for ADHD and Oppositional-Defiant Disorder. Axis I psychiatric comorbidities were evaluated with the SCID-I and smoking behavior with Fagerström Test for Nicotine Dependence (FTND). Personality was evaluated with Cloninger’s Temperament and Character Inventory (TCI). Results: The presence of smoking was strongly associated with externalizing characteristics as antisocial personality disorder (OR 4.2) and substance dependence (OR 6.5), but not with internalizing disorders. Moreover, smoking was associated with higher novelty seeking and lower harm avoidance scores. Conclusions Smoking initiation among patients with ADHD is consistent with a behavioral disinhibition profile beyond the possible role of self-medication in smoking persistence. Smoking in these patients is strongly associated with externalizing comorbid disorders.
Objective: This study addresses if deficits in cognitive, attention, and inhibitory control performance in adults with ADHD are better explained by the disorder itself or by comorbid conditions. ...Method Adult patients with ADHD (n = 352) and controls (n = 94) were evaluated in the ADHD program of a tertiary hospital. The diagnostic process for ADHD and comorbidities was based on Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) criteria. Stepwise regression analyses evaluated the effect of ADHD, demographics, and comorbidities on the scores from Wechsler Adult Intelligence Scale–Revised, Continuous Performance Test, and Stroop Color and Word Test. Results: Patients with ADHD of both genders had worse performance on neuropsychological domains, even after adjustment for comorbidities. The presence of comorbid bipolar disorder and specific phobia are associated with more Stroop errors, whereas patients with generalized anxiety disorder present a longer execution time in Stroop. Conclusion: Neuropsychological deficits in adults with ADHD go beyond comorbidity. Specific comorbid disorders may influence the neuropsychological functioning in adults with ADHD.
Although the identification of reliable predictors of methylphenidate response in adults with attention-deficit/hyperactivity disorder (ADHD) is necessary to guide treatment decisions, very few data ...exist on this issue. Here, we assessed the predictors of clinical response to immediate-release methylphenidate hydrochloride (IR-MPH) in a naturalistic setting by analyzing the influence of demographic factors, severity, and a wide range of comorbid psychiatric disorders. Two hundred fifty adult patients with ADHD were evaluated and completed a short-term treatment with IR-MPH. Mental health diagnoses were based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria through the use of standard structured interviews. The Swanson, Nolan, and Pelham Rating Scale, version 4, adapted to adults was used to assess the severity of ADHD. In the linear regression model, only higher severity of ADHD was associated to a better IR-MPH response (b = 0.770; P < 0.001). Treatment of comorbidities in a subsample (n = 62) did not modify this pattern. Our findings suggest that in clinical settings, patients with more severe ADHD symptoms have a good response to treatment independently from the presence of mild or stabilized comorbidities and their treatments. For adults with ADHD, differently from other common psychiatric disorders such as depression and anxiety, higher severity is associated with better treatment response.
