Elevated blood serotonin in autistic probands and their first-degree relatives.
High blood serotonin clusters in autism families, a lab curiosity that keeps showing up but does not guide behavior plans.
01Research in Context
What this study did
Martens et al. (1989) drew blood from autistic children and their parents and siblings.
They checked serotonin levels in each family member.
The study was small and only described the numbers; it did not test any treatment.
What they found
Serotonin was high in the autistic child and also high in many relatives.
The same pattern showed up across several families.
How this fits with other research
Aldred et al. (2003) later found the same family pattern with amino acids, so the idea of shared body chemistry in autism families keeps growing.
Quadros et al. (2018) saw a similar trend with folate receptor autoantibodies, adding another familial marker you might see on lab reports.
Yuwiler et al. (1992) looked for special serotonin antibodies in autism, schizophrenia, and other conditions but found none, showing the high serotonin itself is more useful than looking for antibodies against it.
Why it matters
You cannot treat serotonin levels with ABA, yet knowing they run in families helps you read medical charts. When a parent mentions gut issues, mood meds, or immune problems, you can nod and stay collaborative. High serotonin is only a clue, not a therapy target, but it reminds us to think about the whole family when planning support.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →When Mom says she also takes SSRI meds, just note it—no change to programs, just richer context.
02At a glance
03Original abstract
Whole blood serotonin levels and platelet counts were studied in 14 families, representing 57 family members and 15 probands who met DSM III criteria for infantile autism. High serotonin appeared to segregate in families. When two parents had high serotonin, the serotonin level in their offspring was twice the parental level. When one parent had high serotonin, the serotonin level in the offspring approximated the level of serotonin in either the high serotonin parent or the low serotonin parent. For the case where both parents had low serotonin, in one family the children had low serotonin and in a second family, high serotonin levels were present in the autistic proband, and a sibling with severe mental retardation. Mean serotonin levels were higher for both male and female, autistics and family members, in the four black families than in the 10 Caucasian families.
Journal of autism and developmental disorders, 1989 · doi:10.1007/BF02212938