Related Experiment Video
Updated: Aug 24, 2026

Use of a Video Scoring Anchor for Rapid Serial Assessment of Social Communication in Toddlers
Published on: March 14, 2018
Platelet serotonin levels in pervasive developmental disorders and mental retardation: diagnostic group differences,
Erik J Mulder1, George M Anderson, Ido P Kema
1Child and Adolescent Psychiatry Center, University of Groningen, The Netherlands. e.j.mulder@accare.nl
Objective:
To investigate group differences, the within-group distributions, and the clinical correlates of platelet serotonin (5-HT) levels in pervasive developmental disorders (PDD).
Method:
Platelet 5-HT levels were measured in Dutch children and young adults, recruited from 2001 through 2003, with PDD (autism, Asperger's, and PDD-not otherwise specified [PDD-NOS]; n = 81) or with mental retardation (MR; n = 54) but without PDD, and in normal controls (n = 60). The distribution of platelet 5-HT levels was assessed using mixture-modeling analyses. Relationships between platelet 5-HT levels and a full range of demographic, clinical, and behavioral variables were examined.
Results:
Group mean (+/- SD) platelet 5-HT levels (nmol/10 platelets) were significantly higher in the autistic (4.51 +/- 1.61, n = 33) and PDD-NOS (4.90 +/- 1.54, n = 43) groups compared to the MR (3.48 +/- 1.33, n = 54) or the normal control (3.58 +/- 1.08, n = 60) groups (F4,190 = 9.35, p <.001). Platelet 5-HT values in the combined PDD group showed a bimodal distribution, and an empirical cutpoint for hyperserotonemia was determined. None of the behavioral variables examined was significantly associated with platelet 5-HT levels.
Conclusions:
The platelet hyperserotonemia of autism was replicated in Dutch subjects. Platelet 5-HT levels were also increased in PDD-NOS, while no elevation was seen in MR. Platelet 5-HT levels appeared to be bimodally distributed in the PDD group, with an apparent hyperserotonemic subgroup.
Related Concept Videos
Autism Spectrum Disorder
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.
Diagnostic and Statistical Manual of Mental Disorders (DSM)
Attention-Deficit/Hyperactivity Disorder
Diagnostic Criteria and Symptoms
To diagnose ADHD, symptoms must manifest before age 12 and be evident across multiple settings.