Why Your Brain is Stuck: The Truth About Psychedelics and Plasticity

0:29:20 Mark Hyman (host)contradictedmoderate

The human brain releases DMT at birth and upon death.

"And I know when you're born and when you die, you have a release of DMT in your brain that is normally there in small amounts." (said at 0:29:20)

The assertion that the human brain releases N,N-dimethyltryptamine (DMT) during birth and death is a popular speculative hypothesis that is not supported by scientific evidence in humans. While trace amounts of endogenous DMT and its synthesizing enzymes have been detected in mammalian tissues, review of the pineal gland's biosynthetic capacity indicates it cannot produce the quantities necessary to cause psychoactive effects (PMID: 29095071). Although one animal study observed an increase in extracellular DMT in the visual cortex of rats during experimentally induced cardiac arrest (PMID: 31249368), no human studies have demonstrated a surge or release of DMT at birth or death.

contradicts: N,N-dimethyltryptamine and the pineal gland: Separating fact from myth. (Journal of psychopharmacology (Oxford, England) 2018) · cited 69x in the literature
"Recent incarnations of these notions have suggested that N,N-dimethyltryptamine is secreted by the pineal gland at birth, during dreaming, and at near death to produce out of body experiences. Scientific evidence, however, is not consistent with these ideas. The adult pineal gland weighs less than 0.2 g, and its principal function is to produce about 30 µg per day of melatonin... It is clear that very minute concentrations of N,N-dimethyltryptamine have been detected in the brain, but they are not sufficient to produce psychoactive effects." (abstract, results and conclusions, passage verified)
pubmed full study (doi)
context: Biosynthesis and Extracellular Concentrations of N,N-dimethyltryptamine (DMT) in Mammalian… (Scientific reports 2019) · cited 115x in the literature
"A significant increase of DMT levels in the rat visual cortex was observed following induction of experimental cardiac arrest, a finding independent of an intact pineal gland. These results show for the first time that the rat brain is capable of synthesizing and releasing DMT at concentrations comparable to known monoamine neurotransmitters and raise the possibility that this phenomenon may occur similarly in human brains." (abstract, results, passage verified)
pubmed full study (doi)

1:02:29 Robin Carhart-Harriscontradictedhigh

Lexapro works by releasing serotonin and bathing the brain in more serotonin to help take the edge off stress.

"The Lexapro will release serotonin, sort of bathe the brain in more serotonin, which helps you get by. It takes the edge off stress." (said at 1:02:29)

The speaker misstates the primary pharmacological mechanism of Lexapro (escitalopram). Escitalopram is a selective serotonin reuptake inhibitor (SSRI), not a serotonin-releasing agent. It works by binding to the serotonin transporter (SERT) and blocking the presynaptic reuptake of endogenous serotonin from the synaptic cleft, rather than stimulating or releasing serotonin directly into the brain.

contradicts: Escitalopram, an antidepressant with an allosteric effect at the serotonin transporter--a … (Psychopharmacology 2012) · cited 108x in the literature
"The primary target for escitalopram is the serotonin transporter (SERT), which is responsible for serotonin (or 5-hydroxytryptamine [5-HT]) reuptake at the terminals and cell bodies of serotonergic neurons. Escitalopram and selective serotonin reuptake inhibitors bind with high affinity to the 5-HT binding site (orthosteric site) on the transporter. This leads to antidepressant effects by increasing extracellular 5-HT levels which enhance 5-HT neurotransmission." (abstract, results, passage verified)
pubmed full study (doi)
contradicts: Selective Serotonin Reuptake Inhibitors and Adverse Effects: A Narrative Review. (Neurology international 2021) · cited 432x in the literature
"The primary mechanism of action of SSRIs is to inhibit presynaptic reuptake of serotonin at the serotonin transporter, subsequently increasing serotonin at the postsynaptic membrane in the serotonergic synapse." (abstract, results, passage verified)
pubmed full study (doi)

Why Your Brain is Stuck: The Truth About Psychedelics and Plasticity

Contradicted by research

The human brain releases DMT at birth and upon death.

Lexapro works by releasing serotonin and bathing the brain in more serotonin to help take the edge off stress.