We all remember that public service announcement. But is it true? There are multiple studies, including the much respected Epilepsy Foundation now cautiously recommending CBD for the treatment of certain types of seizures in children. On the opposite side, the National Association of School Nurses resolutely recognizes the negative effects of marijuana, without any exploration into its potential uses. With growing brains, how does CBD affect brain development and intelligence?
There are several key processes and structures in human brain development and maturation takes more than 20 years. The first phase, in utero, is neuronal migration. Neuronal migration is a 3-month process and creates 3 main layers in the brain. Wrong positioning in this early phase can lead to incorrect or missing synaptic connections.
From birth to age three, myelination occurs. It proceeds from the head down, with the nervous system gradually forming insulation around nerve cells and the motor skills improving. This process will continue into early childhood. Synaptic connections improve (synaptogenesis). The growth of new synapses slows. Unused or poor connections are “pruned.” Synaptic pruning saves some unused synapses to allow the brain to evolve and adapt as needed.
During this phase of increased brain development, the prefrontal cortex undergoes rapid growth and reorganization. The prefrontal cortex is where the highest cognitive and emotional control happens. These executive functions direct complex mental processes required to:
These neural networks are at peak neuroplastic responsiveness. Synaptic creation slows and more active “pruning” goes on.
As myelination progresses, attention spans and speed of processing improve. A shift to the logic centers of the prefrontal cortex happens as the brain matures. A switch to thoughtful responses over emotional actions generated in the primitive amygdala comes at a cost. The switchover comes with a loss of empathy, as adolescents are dramatically less likely to recognize another’s emotions. The hyperplasticity if the early childhood years somewhat reduces as more of the prefrontal cortex comes into play.
The human brain continues development until about the age of 25. The corpus callosum (the part connecting both hemispheres in the brain) and prefrontal cortex continue to grow in complexity into adulthood. It’s one of the reasons that young adults are known for their poor decision-making!
CBD is a non-psychoactive component of cannabis sativa and does not make you feel high. The major active ingredient in cannabis that does provide a high is THC. There is mounting evidence that THC is not without risk to brain development.
Several decades of research have identified some the chemical pathways responsible for executive functions of thinking, moving and feeling in the brain. Specifically, these are housed in the prefrontal cortex. The endocannabinoid (EC) system acts as a modifier to neurotransmitters moving from cell to cell.
Cannabinoid receptors in the neurons take natural cannabinoids made by the fat cells to modify, intensify or block signals to release or absorb dopamine. THC overwhelms this system and fills the cannabinoid receptors, flooding the brain with dopamine. Repeated exposure to even low levels of THC in adolescents can have long-term or permanent effects on the EC system. Changing the EC system for even a short period of time can have neurochemical and neurostructural effects. Early adolescence-onset use is correlated with poor outcomes in adulthood.
This because at adolescence CB1 receptors proliferate in the human brain. Disruption of their growth may have bad effects. In adults, CB1 receptors are fully formed and excess neurons are “pruned” down. Research indicates that normal brain development of CB1 receptors in neonatal and young animal models is slow, suggesting that very young children may not experience a “high” at all from THC. Damage to the receptors may not result in permanent harm.
Studies with adults seem to indicate that CBD has a neuroprotective role. CBD does not seem to be active in the same way that THC is. It does not bond with CB1 receptors (the dopamine receptors) and is not shown to be active in CB2 receptors. CBD indirectly affects signaling through CB1 and CB2 receptors. CBD increases levels of the body’s own endocannabinoids by inhibiting their breakdown. Still under research are the influences CBD has on the non-EC receptors in the brain.
These include receptors for pain regulation, the opioid targets of most pharmaceutical painkillers. This is of interest because of the potential for opioid abuse. CBD has potential use in regulating aspects of behavior and cognition through interaction with dopamine receptors. CBD directly activates serotonin receptors in the brain. CBD’s anti-anxiety and anti-depressive properties are influenced by this system. Serotonin is primarily found in the blood platelets and gastrointestinal system.
Common anti-depressants work by increasing the amount of serotonin available for the receptors. They both increase the amount of serotonin produced and prevent its destruction. CBD’s mechanism differs, but the reported results deserve study. So far, there are very limited published studies of the effects of CBD that use isolated CBD or low THC strains with children. Adult studies indicate, however, that CBD limits cell damage after stroke and protects against neurodegeneration.
Non-permanent changes were seen in neuroplasticity, similar to anti-psychotic and anti-depressant drugs. Trauma patients saw less damage and faster recovery. Adults showed hippocampal neurogenesis with the use of cannabis (whole plant, not isolated compounds.) Flooding the brain with cannabinoids stimulates the growth of neurons to “catch” all the neurotransmitters. This happens even beyond the age at which neural growth is usually restricted.
Cell growth was rapid and undifferentiated. This indicates some promise for persons with brain damage but seems counter-intuitive for the treatment of children already undergoing rapid changes.
More research on CBD’s interactions with the growing brain is needed. Most studies on children’s brain development and cannabis are focused on THC and recreational smoking. There are several intriguing avenues of possibility. For example, use of CBD or other non-psychoactive compounds to treat addiction, obsessive behaviors or anxiety in adults could indicate a use in children to PREVENT those behaviors.
There are many indicators that treatment of ADHD/ADD in adults is successful with CBD. With the prevalence of amphetamine use as an ADHD treatment in children, the use of CBD seems benign. Preventative treatment of traumatic brain injuries with cannabis seems counter to conventional wisdom, but a body of researchers is examining the use of various terpenes to reduce inflammation and cell death. CBD acts on enzymes related to cell death and greatly slows neurodegeneration.
There is zero definitive evidence suggesting that CBD affects brain development. What evidence that does exist is focused on THC. Whether or not evidence suggests cannabis affects brain development depends on the age of the user. For children and young teens, non-medical use of THC should be avoided. CBD seems to be an appropriate medical treatment with caution. There needs to be more study on how specific cannabinoids work in the brain and studies of long-term effects of cannabis in general. For more information about various strains and ongoing research, check out our blog along with our archive of scientific studies.
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