Does acetaminophen cause autism – or not?

Here are two resources I want share on this topic have provided me with some clarity:

– An article by Peter McCullough MD MPH

Peter is a highly respected cardiologist who has been quite vocal about the pandemic and it’s after effects ever since it started 

– A podcast by Peter Attia MD which reviews in depth some key studies on this topic – https://tinyurl.tools/e1b95f87

The Takeaway?

Acetaminophen may have a minor/negligible impact on the development of ASD – Autism Spectrum Disorder – or even none 

Following is the article by Peter McCullough

Confounded Association Between Prenatal Tylenol and Childhood Neuropsychiatric Disorders

Large, Conclusive Swedish Study Finds Relationship, Demonstrates Lack of Independence

PETER A. MCCULLOUGH, MD, MPH

Before the recent HHS press briefing on autism, there was little or no discussion on mainstream, social, or Substack media on acetaminophen use during pregnancy. Many did not know Tylenol is one of many drugs implicated.

An AI search found at least thirty drugs used during pregnancy “linked” to neuropsychiatric problems later on in the child.

There are numerous prenatal drugs and substances that have been associated with increased risk of childhood neuropsychiatric or neurodevelopmental disorders (such as autism spectrum disorder, ADHD, intellectual disability, anxiety, depression, behavioral problems, or cognitive deficits) in the scientific literature. Based on a synthesis of peer-reviewed sources (including systematic reviews, cohort studies, and meta-analyses from PubMed, JAMA, BMJ, and other databases), at least 30 specific drugs have been associated with these risks to varying degrees. Citations are rendered inline where direct sources are available.

Anticonvulsants/Antiseizure Medications (5+ drugs) These are commonly linked to neurodevelopmental risks, especially autism and intellectual disability, due to interference with brain development.

• Valproic acid/valproate: Strongly associated with ASD (up to 7-fold increased risk), lower IQ, and behavioral disorders.jamanetwork.com +3
• Carbamazepine: Neural tube defects and potential cognitive delays.womensmentalhealth.org
• Phenytoin: Linked to developmental delays and cognitive deficits (though evidence is weaker than for valproate).pmc.ncbi.nlm.nih.gov
• Topiramate: Increased risk of ASD and intellectual disability.med.stanford.edu
• Lamotrigine: Mixed evidence; some studies show weak links to oral clefts or learning difficulties, but often considered lower-risk.aafp.org +1

Antidepressants (15+ drugs) Prenatal exposure, especially in the first trimester, has been linked to ASD, ADHD, altered brain development, and behavioral issues, though evidence is conflicting and often tied to underlying maternal depression.

• SSRIs (selective serotonin reuptake inhibitors) as a class: Increased ASD risk (up to 2-fold) and altered pain response or stress axis function.womensmentalhealth.org
  • Fluoxetine: Autism-like behaviors, lifelong behavioral abnormalities, altered serotonin function.
  • Paroxetine: Attention problems, aggression, hyperactivity.
  • Sertraline: Cognitive and behavioral changes.
  • Citalopram: Neonatal distress with potential long-term behavioral effects.
  • Escitalopram: Musculoskeletal defects and psychomotor delays.
• TCAs (tricyclic antidepressants) as a class: Neonatal syndrome, long-term behavioral changes (e.g., altered social interaction, cognition).
  • Amitriptyline: Developmental delays, central nervous system effects.
  • Clomipramine: Autism-like responses, reduced anxiety in models.
  • Desipramine: Altered behavioral responsiveness.
  • Imipramine: Behavioral changes, altered brain histology.
  • Nortriptyline: Decreased body weight and potential developmental effects (animal models).
  • Trimipramine: Major abnormalities (animal models).
• SNRIs (serotonin-norepinephrine reuptake inhibitors): Similar to SSRIs; disrupted behaviors.
  • Venlafaxine: Decreased exploratory/social behaviors.
• Atypical antidepressants: Anxiety-like behaviors.
  • Bupropion: Increased anxiety, stress vulnerability, substance sensitivity.
  • Trazodone: Decreased exploratory/social behaviors.
• MAOIs (monoamine oxidase inhibitors): Limited data, but linked to ASD.
  • Selegiline: Increased ASD risk.

Antipsychotics (7+ drugs) Associated with neurodevelopmental disorders and learning difficulties, though evidence is emerging and often for neonatal withdrawal rather than long-term effects.

• Typical antipsychotics as a class: Potential congenital malformations.
  • Haloperidol: Teratogenic risks low, but neonatal effects.
  • Perphenazine: Malformations (low-potency agents).
  • Trifluoperazine: Similar to above.
• Atypical antipsychotics as a class: Risk of specific neurodevelopmental disorders; neonatal extrapyramidal signs or withdrawal.sciencedirect.com
  • Olanzapine: No major malformations, but neonatal complications.
  • Risperidone: Similar neonatal risks.
  • Quetiapine: Obstetrical/neonatal complications.
  • Clozapine: Limited data; potential malformations.
  • Aripiprazole: Limited data.

Opioids (4+ drugs)Linked to lower cognitive/motor skills, ADHD, and behavioral disorders, though not always substantial increases.  bmj.com +4

• Methadone: Lower mental development, neurodev impairment.
• Morphine: Altered stress responses, anxiety-like behaviors.
• Oxycodone: Similar to morphine; long-term morbidity.
• Buprenorphine: Neonatal withdrawal, behavioral changes.

Other Medications (3+ drugs)

• Acetaminophen: Increased risk of NDDs (e.g., autism, ADHD) and other neuropsychiatric disorders.ehjournal.biomedcentral.com +1
• Benzodiazepines (class): Possible increased risk of learning/neuropsychiatric disorders, cleft lip/palate (weak long-term data).womensmentalhealth.org
• Synthetic glucocorticoids (e.g., dexamethasone, betamethasone): Attention problems, executive dysfunction, cortical thinning.pmc.ncbi.nlm.nih.gov

As an epidemiologist and a long-standing journal editor, I have become skilled at determining and examining the best and most conclusive sources of evidence among many publications on a topic. The reported link between prenatal acetaminophen use and the development of neuropsychiatric disorders several years later in the child is best evaluated by Ahlqvist et al, JAMA 2024.