Dude, where's my medicine? Prescription marijuana without the memory loss on the horizon

By Claire Bates
Updated:

The cannabis plant has pain-relieving properties but can also increase the risk of memory problems and psychosis

The cannabis plant has pain-relieving properties but can also increase the risk of memory problems and psychosis

Marijuana is commonly used for pain relief in many U.S states, but has regrettable side-effects such as making you forgetful.

Now scientists have pinpointed the part of the brain where the drug hinders working memory and discovered it is a separate area to where it has a medicinal effect.

They say the findings raise the possibility that they could design a cannabis drug that is able to treat pain and seizures without hurting the memory.

The team, led by Giovanni Marsciano from the French biomedical institution INSERM, found that marijuana eased pain via the neurons in the brain. However, the main psychoactive ingredient (THC) impaired memory via the astroglia - passive support cells that play second fiddle to active neurons.

In a study on mice, the researchers looked at how their brain cell receptors reacted to THC, found in marijuana.

They found animals engineered to have no receptors on the astroglial cells of the brain were protected from impairments to working memory and were able to complete a maze.

However, animals that lacked the same receptors - known as CB1Rs - on their neurons but did have them on the astroglial cells suffered memory lapses when exposed to THC.

Dr Marsciano said there could be a way to activate the receptors on neurons while leaving these secondary cells out.

Cannabis

Cannabis is a Class B drug in the UK but can be used for medicinal purposes in 18 U.S states

Medical marijuana is currently legal in 18 U.S states including California. However, in the UK marijuana - also known as cannabis - is a Class B drug and so illegal to have or give away. It has been approved for use in some long-term medical trials.

A study from the the University of California San Francisco and University of Alabama at Birmingham, found smoking cannabis is less harmful to users’ lungs than exposure to tobacco.

However, frequent cannabis use has been associated with anxiety, schizophrenia, bipolar disorders and depression. It has also been found to affect learning for weeks after exposure.

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