OBJECTIVES: This study aimed to systematically summarise all global evidence on the economic burden of ADHD.
METHODS: A systematic search for published studies on costs of ADHD was conducted in EconLit, EMBASE, PubMed, ERIC, and PsycINFO. Additional literature was identified by searching the reference lists of eligible studies. The quality of the studies was assessed using the Larg and Moss checklist.
RESULTS: This review included 44 studies. All studies were conducted in high-income countries and were limited to North America and Europe except for four studies: two in Asia and two in Australia. Most studies were retrospective and undertook a prevalence-based study design. Analysis revealed a substantial economic impact associated with ADHD. Estimates based on total costs ranged from $US831.38 to 20,538 for per person estimates and from $US356 million to 20.27 billion for national estimates. Estimates based on marginal costs ranged from $US244.15 to 18,751.00 for per person estimates and from $US12.18 million to 141.33 billion for national estimates. Studies that calculated economic burden across multiple domains of direct, indirect, and education and justice system costs for both children and adults with ADHD reported higher costs and translated gross domestic product than did studies that captured only a single domain or age group.
CONCLUSIONS: Despite the wide variation in methodologies in studies reviewed, the literature suggests that ADHD imposes a substantial economic burden on society. There is a dire need for cost-of-illness research in low- and middle-income countries to better inform the treatment and management of ADHD in these countries. In addition, guidelines on the conduct and reporting of economic burden studies are needed as they may improve standardisation of cost-of-illness studies.
METHODS: We analysed genome-wide single-nucleotide polymorphism (SNP) data for the five disorders in 33,332 cases and 27,888 controls of European ancestory. To characterise allelic effects on each disorder, we applied a multinomial logistic regression procedure with model selection to identify the best-fitting model of relations between genotype and phenotype. We examined cross-disorder effects of genome-wide significant loci previously identified for bipolar disorder and schizophrenia, and used polygenic risk-score analysis to examine such effects from a broader set of common variants. We undertook pathway analyses to establish the biological associations underlying genetic overlap for the five disorders. We used enrichment analysis of expression quantitative trait loci (eQTL) data to assess whether SNPs with cross-disorder association were enriched for regulatory SNPs in post-mortem brain-tissue samples.
FINDINGS: SNPs at four loci surpassed the cutoff for genome-wide significance (p<5×10(-8)) in the primary analysis: regions on chromosomes 3p21 and 10q24, and SNPs within two L-type voltage-gated calcium channel subunits, CACNA1C and CACNB2. Model selection analysis supported effects of these loci for several disorders. Loci previously associated with bipolar disorder or schizophrenia had variable diagnostic specificity. Polygenic risk scores showed cross-disorder associations, notably between adult-onset disorders. Pathway analysis supported a role for calcium channel signalling genes for all five disorders. Finally, SNPs with evidence of cross-disorder association were enriched for brain eQTL markers.
INTERPRETATION: Our findings show that specific SNPs are associated with a range of psychiatric disorders of childhood onset or adult onset. In particular, variation in calcium-channel activity genes seems to have pleiotropic effects on psychopathology. These results provide evidence relevant to the goal of moving beyond descriptive syndromes in psychiatry, and towards a nosology informed by disease cause.
FUNDING: National Institute of Mental Health.
AIM: The purpose of this study was to determine the relationship between Soil Transmitted Helminth infection on levels of eosinophils among primary school children. In addition, this study also aimed to determine the prevalence of different types of worm infections and the levels of eosinophils in children infected with worms.
MATERIAL AND METHODS: This study was analytic observational using a cross-sectional method. The sampling technique was consecutive and in total 132 samples was obtained. The study involved primary school children in Amplas Medan and Hamparan Perak, Deli Serdang through May to October 2016. Univariate analysis was performed to determine STH infection prevalence and bivariate analysis was used to find the correlation between STH infection and eosinophil levels through a Chi square (χ2) test.
RESULTS: The results showed that the prevalence of Soil Transmitted Helminth was 7.6%. The most common types of STH infection were 3.8% with Trichuris trichiura and 3% with Ascaris lumbricoides. A significant correlation was found between Parasite infection and eosinophil levels (Contingency Coefficient (C) = 0.2, χ2 = 5.3, p = 0.021) and the risk of STH infection that caused eosinophilia or increased eosinophil levels in the children with a Prevalence Ratio (PR) of 1.56 (Confidence Interval (CI) 95%: 1.10-2.22).
CONCLUSION: It is recommended that schools at similar risk improve and maintain hygiene and healthy behaviour in the school environment and that parents and teachers pay greater attention to the cleanliness of their children.