China science

Smoke that joint, private! Dopamine-boosters like marijuana inhibit fear and could keep troops in battle, Chinese scientists claim

Pentagon may legalise use of recreational drug if US Democrat Bernie Sanders wins this year’s presidential race, and new Chinese study claims to confirm for first time how weed can turn weeds, or cowards, into heroes

PUBLISHED : Tuesday, 26 January, 2016, 2:31pm
UPDATED : Monday, 12 June, 2017, 12:53pm

Ever watched a Hollywood movie about the Vietnam War that includes scenes of, or references to, GIs smoking marijuana in their barracks during their tours of duty?

That may become standard operating procedure in future US military operations, depending on the outcome of this year’s US presidential race, and a new study by Chinese scientists on how dopamine functions suggests that smoking the occasional joint may even bring out the best in the troops, at least when gripped by terror.

While recreational drug use of this nature is currently banned by most militaries worldwide, there is increasing support for their legalisation in the armed forces of countries such as the United States.

Washington has funded many projects studying the mechanism and effects of dopamine because of its important role in so many brain-related functions.

Researchers believe a better understanding of the chemical could result in better treatments for drug addicts and even possible cures for neurological disorders like depression, schizophrenia and Parkinson’s.

Meanwhile, Vermont senator Bernie Sanders, a Democratic candidate for this year’s presidential race, has openly declared that he will lift the Pentagon’s ban on marijuana if elected.

This has met with a chorus of approval by many young men and women in military service in the country, according to recent US media reports.

While the majority may appreciate the “high” or feelings or relaxation and “escape” the drug produces, the logic behind introducing it to the military is precisely because it can have the opposite effect. According to the Chinese researchers, it can be used to stop people fleeing battle by controlling their fear.

WATCH: Vietnam War soldiers smoking “the peace pipe”

Dopamine, a neurotransmitter that regulates the body’s pain and reward centres, was found to control feelings of fear by blocking visual signals from reaching the neurons that dictate a person’s natural fight-or-flight response when under threat, the team said.

As marijuana increases the production of dopamine in the brain, it could be used to stop troops deserting under pressure of battle, or simply to boost morale, they argued.

“In theory, the likelihood of troops trying to escape battle out of fear could be reduced if they were dosed with dopamine-boosting drugs like marijuana,” said Professor Du Jiulin at the Institute of Neuroscience, part of the Shanghai Institutes for Biological Sciences (SIBS), which operates under the Chinese Academy of Sciences (CAS).

Prof. Du led the research team that reported their findings in the latest issue of the journal Neuron.

Although dopamine is known to be involved in how the adrenal glands work, scientists have found it hard to track its propagation in the brain and body of a living animal to determine how it affects certain forms of behaviour.

Du’s team took a novel approach by basing their experiments not on humans or lab rats but zebrafish, which are almost transparent during the early stages of their life.

Using genetic engineering, the team created baby zebrafish with brain cells that emit florescent light, so that they could better study the operation of the drug in their system.

When the fish were exposed to non-threatening objects like rocks or grass, the neurons responsible for producing dopamine were activated. This ramped up their confidence, as the chemical inhibited “visual information transmission from the visual centre to the motor command neuron,” according to their paper.

“In contrast, threatening stimuli suppresses these (dopamine-producing) neurons’ activation, leading to dis-inhabitation of visual information transmission and generation of escape behaviour,” the authors added.

But Du warned that other potential side effects of marijuana - such as its addictiveness or hallucinatory properties - could compromise its usefulness among the military, and said further studies were required.

“It’s possible that marijuana could reduce their willingness to escape, but also their willingness to fight, which wouldn’t be such good news for a military commander after all,” he added.

Professor Li Jian, principal investigator at the Department of Psychology at Peking University, said the discovery by Du’s team was “not at all surprising”.

“Most of our emotions and behaviour, if not all, are controlled by chemicals in the brain,” said Li, who was not involved in the study.

“Revealing the mysterious working mechanism of these chemicals will profoundly change the way of people give, or take, instructions,” he added.