Regular cocaine and cannabis use may trigger addictive behaviours

October 28, 2013, British Journal of Pharmacology

New cocaine and cannabis research reveals that regular cannabis users have increased levels of impulsive behaviour. It had previously been argued that this increased impulsivity after cannabis administration was only experienced by occasional users, but that regular users were no longer affected in this way. Published in the British Journal of Pharmacology, the results provide evidence for how drug use may trigger addictive behaviours.

In a study conducted in the Netherlands, 61 healthy regular cannabis and cocaine took both drugs and a placebo in controlled conditions. They then took part in tests that challenged them to reflect before making an action. "If a person's tendency to be impulsive increases, they tend to make snap decisions and the error rate increases," says lead researcher Janelle van Wel from Maastricht University. The participants were also studied in situations where they were asked to perform an action, but then told to stop. In this set of tests, people with higher levels of impulsivity make more mistakes and have delayed stopping times. Tests also assessed critical thinking skills, divided attention challenges and aspects of executive function and planning.

Both cannabis and cocaine increased impulsive responding, but in opposite ways. Under the influence of cannabis, subjects were slower, but made more errors. Cocaine administration caused the participants to react more quickly, but if participants had to control their impulses they made more errors. "This increased after drug use could increase the likelihood of developing addiction," says Ms. van Wel.

Taken together, the results indicate that long-term users of cocaine and cannabis were more impulsive under the influence of the drugs than when they were given placebos. "These findings contrast with previous reports that had claimed that these effects after cannabis administration only occurred in occasional users and not in heavy users," says Ms. van Wel. Regular cannabis users experienced impairments, but had about a 2-3 times reduction in the magnitude of the impairments in two of the tests compared with occasional cannabis users.

One hallmark of drug addiction is a disturbed relationship between the frontal cortex where decisions are made and the limbic system that organises emotional responses and memory. These results indicate that could decrease the amount of control the exerts over behaviour, while could increase impulsive responding from the limbic system. "Both of these options would cause the decrease in impulse control we see in our study," says Ms. van Wel, who believes that future studies using imaging techniques could clarify this hypothesis.

Explore further: Long-term cannabis use may blunt the brain's motivation system

More information: van Wel et al. Single Doses of THC and cocaine decrease proficiency of impulse control in heavy cannabis users, British Journal of Pharmacology 2013. DOI: 10.1111/bph.12425

Related Stories

Long-term cannabis use may blunt the brain's motivation system

July 1, 2013
Long-term cannabis users tend to produce less dopamine, a chemical in the brain linked to motivation, a study has found.

Cannabis link to other drugs

July 19, 2011
Quitting cannabis use in your 20s significantly reduces the chance of progressing to other illicit drugs, according to research published in the Journal of Epidemiology and Community Health.

Stoners beware: Exercising might lead to a positive drug test

September 12, 2013
(Medical Xpress)—Exercise is essential to a healthy lifestyle, but new research led by the University of Sydney shows that for cannabis users, it could also lead to positive drug tests.

Addiction: Can you ever really completely leave it behind?

September 23, 2013
It is often said that once people develop an addiction, they can never completely eliminate their attraction to the abused substance. New findings provide further support for this notion by suggesting that even long-term ...

High levels of THC in Australian cannabis

July 25, 2013
The first systematic analysis of the potency of Australian cannabis has found high levels of tetrahydrocannabinol (THC) – the main psychoactive component of the drug – in samples confiscated by police from recreational ...

Cannabis withdrawal symptoms might have clinical importance

September 26, 2012
Cannabis users have a greater chance of relapse to cannabis use when they experience certain withdrawal symptoms, according to research published Sep. 26 in the open access journal PLOS ONE led by David Allsop of the National ...

Recommended for you

Marijuana use may not aid patients in opioid addiction treatment

December 4, 2017
Many patients who are being treated for opioid addiction in a medication-assisted treatment clinic use marijuana to help manage their pain and mood symptoms.

For opiate addiction, study finds drug-assisted treatment is more effective than detox

November 23, 2017
Say you're a publicly insured Californian with an addiction to heroin, fentanyl or prescription narcotics, and you want to quit.

Study finds medical cannabis is effective at reducing opioid addiction

November 17, 2017
A new study conducted by researchers at The University of New Mexico, involving medical cannabis and prescription opioid use among chronic pain patients, found a distinct connection between having the legal ability to use ...

Insomnia linked to alcohol-use frequency among early adolescents, says new psychology study

November 8, 2017
Insomnia is linked to frequency of alcohol use among early adolescents, according to new Rutgers University–Camden research.

Large declines seen in teen substance abuse, delinquency

October 25, 2017
More than a decade of data indicates teens have become far less likely to abuse alcohol, nicotine and illicit drugs, and they also are less likely to engage in delinquent behaviors, such as fighting and stealing, according ...

Trying to get sober? NIH offers tool to help find good care

October 3, 2017
The phone calls come—from fellow scientists and desperate strangers—with a single question for the alcohol chief at the National Institutes of Health: Where can my loved one find good care to get sober?

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.