Researchers from the National Institute of Drug Abuse in the U.S have conducted an in-depth study into the brains of cannabis users to determine whether or not the drug really does impact on people’s mental health.
The results confirm that cannabis negatively disrupts the functioning of feel-good chemicals in the brain responsible for emotions, feeling positive and motivation.
In the experiment, 48 people were divided into two groups. While one half were given a stimulant called Ritalin – which would highlight the effect of cannabis on the brain – the other half were used as a control group.
Brain and personality scans showed blunted responses of dopamine chemicals in the cannabis users, whilst the controls showed no effects.
The resulting impact of this stunted brain activity is drug-craving and a range of negative emotions.
Most significantly however, it can contribute to an increased tendency towards depression and anxiety – complications which are distinguishing features of cannabis addiction.
Psychiatrists Dr Nora Volkow who led the study explains that while this research is leading, it cannot be unequivocally linked to reductions in dopamine release.
Researchers of the study believe the effect occurs later in the process, in an area of the brain called the striatum – the region of motivation and reward.
This discovery reinforces previous research conducted at Imperial College London suggesting that long-term use of cannabis actually destroys the chemical, dopamine.
The Imperial College research also showed that levels in the striatum were lower in regular cannabis users.
Dr Michael Bloomfield, of Imperial College London, said: “Dopamine is involved in telling the brain when something exciting is about to happen – be it sex, drugs or rock ‘n roll.
“Our findings explain why cannabis has a tendency to make people sit around doing nothing.”