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Thursday, May 15, 2008
Champagne Terrace/Bordeaux (Novotel London West)
Background: Although the autism research literature has grown dramatically in recent years, research on related disorders may suggest topics not yet pursued in pervasive developmental disorder (PDD) research.
Objectives: We sought an objective, quantitative, comprehensive method to compare the topics studied in PDD, related disorders, and biomedicine overall.
Methods: We developed software to analyze >250,000 PubMed records encompassing PDD and disorders with elevated prevalence in PDD (Rzhetsky 2007): ADHD, epilepsy, bipolar disorder, depression, schizophrenia, and others.
We calculated the share of publications indexed by each of >15,000 Medical Subject Heading (MeSH) terms and substance names. We grouped terms using a hierarchy, from molecular to behavioral levels, and by “types” of terms from the Universal Medical Language System (UMLS) ontology. We quantitated occurrences of the terms as the subjects of literature on PDD vs. each disorder. We also compared PDD literature to all of PubMed.
Results: The PDD literature has been far more focused on behavioral/cognitive levels (three times as often), and less on molecular or cellular levels, than biomedical literature overall (56% vs. 38% of publications were indexed with chemical substances in PubMed vs. PDD literature, 2000-2006).
At the molecular level, while almost 2,000 substances were identified in PDD literature, about half appear only once. A handful dominate the literature (MECP2, serotonin, MMR vaccine, risperidone, secretin, thimerosal). Under-studied substances relative to PubMed include TNF-alpha, IL-6, estrogen receptors, insulin, and calcium channels.
We also summarize key symptoms, systems, brain regions, cell types, pathways, and substances studied in comorbid disorders relative to PDD.
Conclusions: Objective and quantitative summaries of topics studied in PDD can inform research prioritization. Our analysis suggests several research topics that have not yet received significant attention in PDD research.
Objectives: We sought an objective, quantitative, comprehensive method to compare the topics studied in PDD, related disorders, and biomedicine overall.
Methods: We developed software to analyze >250,000 PubMed records encompassing PDD and disorders with elevated prevalence in PDD (Rzhetsky 2007): ADHD, epilepsy, bipolar disorder, depression, schizophrenia, and others.
We calculated the share of publications indexed by each of >15,000 Medical Subject Heading (MeSH) terms and substance names. We grouped terms using a hierarchy, from molecular to behavioral levels, and by “types” of terms from the Universal Medical Language System (UMLS) ontology. We quantitated occurrences of the terms as the subjects of literature on PDD vs. each disorder. We also compared PDD literature to all of PubMed.
Results: The PDD literature has been far more focused on behavioral/cognitive levels (three times as often), and less on molecular or cellular levels, than biomedical literature overall (56% vs. 38% of publications were indexed with chemical substances in PubMed vs. PDD literature, 2000-2006).
At the molecular level, while almost 2,000 substances were identified in PDD literature, about half appear only once. A handful dominate the literature (MECP2, serotonin, MMR vaccine, risperidone, secretin, thimerosal). Under-studied substances relative to PubMed include TNF-alpha, IL-6, estrogen receptors, insulin, and calcium channels.
We also summarize key symptoms, systems, brain regions, cell types, pathways, and substances studied in comorbid disorders relative to PDD.
Conclusions: Objective and quantitative summaries of topics studied in PDD can inform research prioritization. Our analysis suggests several research topics that have not yet received significant attention in PDD research.