Navigation Links
Long-term cannabis use may blunt the brain's motivation system
Date:7/1/2013

Researchers found that dopamine levels in a part of the brain called the striatum were lower in people who smoke more cannabis and those who began taking the drug at a younger age.

They suggest this finding could explain why some cannabis users appear to lack motivation to work or pursue their normal interests.

The study, by scientists at Imperial College London, UCL and King's College London, was funded by the Medical Research Council and published in the journal Biological Psychiatry.

The researchers used PET brain imaging to look at dopamine production in the striatum of 19 regular cannabis users and 19 non-users of matching age and sex.

The cannabis users in the study had all experienced psychotic-like symptoms while smoking the drug, such as experiencing strange sensations or having bizarre thoughts like feeling as though they are being threatened by an unknown force.

The researchers expected that dopamine production might be higher in this group, since increased dopamine production has been linked with psychosis. Instead, they found the opposite effect.

The cannabis users in the study had their first experience with the drug between the ages of 12 and 18. There was a trend for lower dopamine levels in those who started earlier, and also in those who smoke more cannabis. The researchers say these findings suggest that cannabis use may be the cause of the difference in dopamine levels.

The lowest dopamine levels were seen in users who meet diagnostic criteria for cannabis abuse or dependence, raising the possibility that this measure could provide a marker of addiction severity.

Previous research has shown that cannabis users have a higher risk of mental illnesses that involve repeated episodes of psychosis, such as schizophrenia.

"It has been assumed that cannabis increases the risk of schizophrenia by inducing the same effects on the dopamine system that we see in schizophrenia, but this hasn't been studied in active cannabis users until now," said Dr Michael Bloomfield, from the Institute of Clinical Sciences at Imperial, who led the study.

"The results weren't what we expected, but they tie in with previous research on addiction, which has found that substance abusers people who are dependent on cocaine or amphetamine, for example have altered dopamine systems.

"Although we only looked at cannabis users who have had psychotic-like experiences while using the drug, we think the findings would apply to cannabis users in general, since we didn't see a stronger effect in the subjects who have more psychotic-like symptoms. This needs to be tested though.

"It could also explain the 'amotivational syndrome' which has been described in cannabis users, but whether such a syndrome exists is controversial."

Other studies have looked at dopamine release in former cannabis users and not seen differences with people who haven't taken cannabis, suggesting that the effects seen in this study are likely to be reversible.


'/>"/>

Contact: Sam Wong
sam.wong@imperial.ac.uk
44-207-594-2198
Imperial College London
Source:Eurekalert

Related medicine news :

1. Non-Compliance With the Affordable Care Act (ACA) Remains a Risk for Long-Term Care Facilities
2. Long-term study reports deep brain stimulation effective for most common hereditary dystonia
3. Long-term apremilast demonstrates continued efficacy in patients with psoriatic arthritis
4. No increased risk of infection for long-term sex partners of people with HPV-related oral cancers
5. Integrated stroke care system results in fewer deaths, discharges to long-term care facilities
6. Sun Damage - The Long-Term Benefits of Sunscreen
7. Long-Term Use of Antibiotic May Help Those With COPD
8. Long-term outcomes in patients with advanced coronary artery disease are better than expected
9. Erectile Dysfunction Tied to Long-Term Narcotic Use in Men
10. Long-term use of prescription painkillers for back pain linked to erectile dysfunction in men
11. BMA Affordable Assisted Living Community to Host Informational Program on Long-Term Care Insurance
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/25/2016)... ... June 25, 2016 , ... ... and applications at AcademyHealth’s Annual Research Meeting June 26-28, 2016, at the Hynes ... important health care topics including advance care planning, healthcare costs and patient and ...
(Date:6/25/2016)... ... June 25, 2016 , ... "With 30 hand-drawn hand gesture animations, FCPX users ... - CEO of Pixel Film Studios. , ProHand Cartoon’s package transforms over 1,300 ... Pro X . Simply select a ProHand generator and drag it above media or ...
(Date:6/25/2016)... Oklahoma (PRWEB) , ... June 25, 2016 , ... ... both athletes and non-athletes recover from injury. Recently, he has implemented orthobiologic procedures ... Oklahoma City area —Johnson is one of the first doctors to perform the ...
(Date:6/24/2016)... ... 2016 , ... A recent article published June 14 on E ... goes on to state that individuals are now more comfortable seeking to undergo not ... as calf and cheek reduction. The Los Angeles area medical group, Beverly Hills Physicians ...
(Date:6/24/2016)... ... June 24, 2016 , ... Marcy was in a crisis. Her son James, eight, was ... his family verbally and physically. , “When something upset him, he couldn’t control his emotions,” ... He would throw rocks at my other children and say he was going to kill ...
Breaking Medicine News(10 mins):
(Date:6/26/2016)... 2016  VMS Rehab Systems, Inc. ( www.vmsrehabsystemsinc.com ) ... measures required to build a strong and stable market ... listed on the OTC Markets-pink current trading platform. ... "We are seeing an anomaly in market trading activities ... by the Company, but shareholders and market players as ...
(Date:6/24/2016)... 24, 2016  Consumers have taken a more ... placed more emphasis on patient outcomes. ... in the pharmaceutical industry have evolved beyond just ... companies are focusing on becoming more patient-oriented across ... and services that improve health. ...
(Date:6/24/2016)... , June 24, 2016  Global Blood Therapeutics, ... company developing novel therapeutics for the treatment of ... announced the closing of its previously announced underwritten ... at the public offering price of $18.75 per ... were offered by GBT. GBT estimates net proceeds ...
Breaking Medicine Technology: