Blood serotonin levels in autism spectrum disorder: A systematic review and meta-analysis

Stefano Gabriele, Roberto Sacco, Antonio M. Persico

Research output: Contribution to journalArticlepeer-review

Abstract

Elevated blood serotonin (5-HT) levels were the first biomarker identified in autism research. Many studies have contrasted blood 5-HT levels in autistic patients and controls, but different measurement protocols, technologies, and biomaterials have been used through the years. We performed a systematic review and meta-analysis to provide an overall estimate of effect size and between-study heterogeneity, while verifying whether and to what extent different methodological approaches influence the strength of this association. Our literature search strategy identified 551 papers, from which 22 studies providing patient and control blood 5-HT values were selected for meta-analysis. Significantly higher 5-HT levels in autistic patients compared to controls were recorded both in whole blood (WB) [O.R.=4.6; (3.1-5.2); P=1.0×10-12], and in platelet-rich plasma (PRP) [O.R.=2.6 (1.8-3.9); P=2.7×10-7]. Predictably, studies measuring 5-HT levels in platelet-poor plasma (PPP) yielded no significant group difference [O.R.=0.54 (0.2-2-0); P=0.36]. Altogether, elevated 5-HT blood levels were recorded in 28.3% in WB and 22.5% in PRP samples of autistic individuals, as reported in 15 and 4 studies, respectively. Studies employing HPLC vs fluorometric assays yield similar cumulative effect sizes, but the former display much lower variability. In summary, despite some limitations mainly due to small study sample sizes, our results significantly reinforce the reliability of elevated 5-HT blood levels as a biomarker in ASD, providing practical indications potentially useful for its inclusion in multi-marker diagnostic panels for clinical use.

Original languageEnglish
Pages (from-to)919-929
Number of pages11
JournalEuropean Neuropsychopharmacology
Volume24
Issue number6
DOIs
Publication statusPublished - 2014

Keywords

  • 5-HT
  • Autism
  • Biomarker
  • Endophenotype
  • Meta-analysis

ASJC Scopus subject areas

  • Clinical Neurology
  • Psychiatry and Mental health
  • Pharmacology (medical)
  • Biological Psychiatry
  • Neurology
  • Pharmacology
  • Medicine(all)

Fingerprint Dive into the research topics of 'Blood serotonin levels in autism spectrum disorder: A systematic review and meta-analysis'. Together they form a unique fingerprint.

Cite this