Smoking weed and tobacco actually shrinks your brain — here are the parts at risk
- Both marijuana and tobacco use are linked to brain shrinkage, particularly in the amygdala, which affects emotional processing, memory, and fear recognition.
- Tobacco smoking is associated with reduced volumes in additional brain areas like the pallidum and insula, impacting movement, motivation, emotion, and self-awareness.
- Regular cigarette smoking decreases total gray matter volume and may significantly reduce hippocampal volume, critical for memory and a marker for dementia.
- Harmful effects of tobacco on the brain are likely due to oxidative stress and inflammation from carcinogens, whereas CBD in cannabis may have protective antioxidative effects.
Add another downside of lighting up to the list.
The risks of smoking are well documented, from the fact that a single cigarette shortens your life to weed not actually helping anxiety or depression.
And while the substances each have different neurological effects, new research has found that both marijuana and tobacco physically affect the brain, resulting in shrinkage.
It’s long been known that aging is linked to a gradual reduction in brain volume, which is a key sign of degenerative conditions — and smoking speeds up the process.
A study published in the journal Addiction reviewed multiple studies looking at associations between cannabis use, tobacco use, co-use and brain volume.
The researchers discovered that cannabis and tobacco use were linked to smaller volumes in the amygdala.
Although it’s a relatively small part of the brain, the amygdala has significant responsibilities, acting as the emotional processing center that manages fear and survival instincts, as well as memory and learning.
A reduced amygdala can result in less ability to regulate emotions, severe anxiety, emotional detachment and the inability to recognize fear, leading to risky behavior.
Smoking tobacco was also connected to smaller volumes in the pallidum and insula.
The pallidum is located deep within the brain and is necessary for smooth, controlled voluntary movement, as well as processing emotions such as motivation, risk and reward.
Shrinkage of the pallidum is often linked to neurodegenerative diseases such as Huntington’s or Alzheimer’s, causing motor and cognitive symptoms.
Considered the hidden “fifth lobe” of the brain, the insula is a primary hub for monitoring internal bodily states such as hunger or pain, generating feelings, cognitive processing and self-awareness.
The study also found that regularly smoking cigarettes reduced total gray matter volume, the brain tissue responsible for processing sensory information, muscle control and decision-making.
There was also strong evidence that smoking more cigarettes per day might significantly decrease hippocampal volumes.
The hippocampus is responsible for learning, short- and long-term memory, spatial awareness, remembering which words to say and recollection of facts or experiences. A reduction in volume is also a key marker for dementia and cognitive impairment.
Many of these various parts work together for full cognitive function, such as the amygdala and hippocampus, which connect emotions and memories for emotional responses.
Tobacco contains thousands of harmful carcinogens, so the researchers believe the harmful effects on the brain could be traced back to oxidative stress and inflammation from these ingredients.
CBD in cannabis, though, has been recognized for its antioxidative and anti-inflammatory effects, which may explain why it didn’t have as much of an effect on the brain.