I've heard that THC can cause permanent damage to brain cells. I've also heard this reffered to anti drug propaganda. Another theory i've read is that temporary effects reduce intelligence but long term results are not affected. If Marijuana does cause permanent brain damage how does it do so? How exactly does it kill the cell?

  • $\begingroup$ @terdon provides some relevant info in a comment here: biology.stackexchange.com/questions/7693/… $\endgroup$
    – blep
    Commented Apr 6, 2013 at 1:46
  • $\begingroup$ @dd3 that post is more about smoking.. Marijuana can be consumed in many more ways.. $\endgroup$
    Commented Apr 8, 2013 at 18:32
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    $\begingroup$ Bear in mind that THC is only the strongest of all the physiologically active substances contained in marijuana (several hundred different ones according to our lecture). Hence, the effect of marijuana can be different from pure THC, especially if the mixture contains toxic leftovers from processing the drug. $\endgroup$
    – Armatus
    Commented Apr 8, 2013 at 19:48

1 Answer 1


There is no damage of brain cells, as in the context of lesions in neurodegenerative disorders. There are, however, two mechanisms attributed to the memory loss associated with cannabis/marijuana and these are purely physiological responses.

  1. Astrocyte mediated: CB1R (cannabinoid receptor) in astrocyte gets activated and promotes glutamate release. This glutamate induces Long Term Depression in post synaptic neuron. Synaptic currents can cause both LTP and LTD. The properties of the synaptic current wave dictates the outcome. Please refer to review articles on LTP and LTD for more information.
  2. GABAergic interneuron mediated: CB1R activation in GABAergic interneurons (inhibitory neurons) causes activation of mTOR pathway and promotes protein synthesis. CB1R activates mTOR through PI3K/Akt.

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