Navigation Links
Schizophrenia linked to dysfunction in molecular brain pathway activated by marijuana

PITTSBURGH, July 7 Alterations in a molecular brain pathway activated by marijuana may contribute to the cognitive symptoms of schizophrenia, according to a report in the July issue of Archives of General Psychiatry, one of the JAMA/Archives journals.

Expression of the cannabinoid 1 receptor (CB1R), the site of action of the main chemical ingredient of marijuana, is significantly reduced in the brains of individuals with schizophrenia. Activation of CB1R impairs signaling by gamma-aminobutyric acid (GABA), an important neurotransmitter essential for core cognitive processes such as working memory. The use of marijuana in individuals with schizophrenia appears to worsen this deficit in GABA synthesis.

Since reduced GABA is known to be present in schizophrenia, these findings suggest possible new drug targets that could help to improve function in people with the mental illness, University of Pittsburgh School of Medicine researchers report.

"Heavy marijuana use, particularly in adolescence, appears to be associated with an increased risk for the later development of schizophrenia, and the course of illness is worse for people with schizophrenia who use marijuana," said David A. Lewis, M.D., corresponding author of the study and UPMC Endowed Professor in Translational Neuroscience, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine. "We wanted to understand the biological mechanisms that could explain these observations, and with this study, I believe that we can narrow down at least part of the 'why' to CB1R, the receptor for both tetrahydrocannabinol (THC), the main psychoactive ingredient in marijuana, and the brains own cannabinoid chemical messengers."

Dr. Lewis and his colleagues examined specimens of brain tissue collected after death from 23 people with schizophrenia and 23 normal comparison subjects matched for a number of factors, including age and sex. The researchers evaluated levels of CB1R messenger RNA and protein, and also measured levels of glutamic acid decarboxylase (GAD-67), an enzyme that makes GABA, and cholecystokinin (CCK), a neuropeptide released from GABA neurons that, among other actions, regulates the production of the brain's own cannabinoids.

"CB1R levels were significantly 15 percent lower in the subjects with schizophrenia," Dr. Lewis said. "We measured these biochemical messengers using three techniques, and each time got the same answer less CB1R in people with schizophrenia." This reduction, he noted, appears to be the brain's way of compensating for lower levels of GABA, and the use of marijuana defeats this compensation.

"These findings may provide insight into the biological basis of why cannabis use worsens schizophrenia, and, as a result, identify a novel target for new drug development that could improve treatments available for schizophrenia," said Dr. Lewis.


Contact: Michele Baum
University of Pittsburgh Schools of the Health Sciences

Related medicine news :

1. Violence declines with medication use in some with schizophrenia
2. Brain Activity May Predict Schizophrenia Behavior
3. Hopkins researchers discover new link to schizophrenia
4. Dr. Mei honored by mental health research charity for schizophrenia studies
5. Schizophrenia: Diagnosis Is Not Destiny - Conference
6. New Drugs No Better Than Older Ones for Schizophrenia
7. Schizophrenia Tied to Multiple Genetic Errors
8. Comparison of antipsychotic treatments in adolescents with schizophrenia
9. New genetic association with schizophrenia found by researchers
10. FDA Issues Not-Approvable Letter for Lillys Zyprexa(R) Long-Acting Injection (LAI) for Schizophrenia Treatment
11. Siblings of schizophrenia patients display subtle shape abnormalities in brain
Post Your Comments:
(Date:11/27/2015)... ... November 27, 2015 , ... The moment you stop improving ... only fulfilling the needs of advisers and clients but going above and beyond ... top-tier customer service. However, there's always room for improvement, which is why the ...
(Date:11/27/2015)... ... November 27, 2015 , ... Avid collector, Andrew Hawley from Vintage Rock Posters, ... posters. This is one of Joplin's most famous and beautiful concert posters. The concert ... Michigan in Ann Arbor. The According to Hawley, "It is hard to believe that ...
(Date:11/26/2015)... ... 26, 2015 , ... Somu Sivaramakrishnan announced today that he ... now offers travelers, value and care based Travel Services, including exclusive pricing on ... as, cabin upgrades and special amenities such as, shore excursions, discounted fares, travel ...
(Date:11/26/2015)... ... November 26, 2015 , ... Pixel Film Studios brings Final ... ProTrailer: Vintage. This newly styled ProTrailer pack comes with 30 all-new vintage-inspired designs, ... giving users limitless opportunities to stylize and create designs quickly and easily, all ...
(Date:11/25/2015)... ... ... The holiday season is jam-packed with family dinners, parties ... is of the utmost importance. Whether you are cooking at home for the ... try this holiday season. , Turkey Croquettes ,     Ingredients: , ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... 26 november 2015 AAIPharma Services ... geplande investering aan van ten minste $15,8 ... en het mondiale hoofdkantoor in ... resulteren in extra kantoorruimte en extra capaciteit ... groeiende behoeften van de farmaceutische en biotechnologische ...
(Date:11/26/2015)... 3D bioprinting market is expected to reach ... by Grand View Research Inc. Rising prevalence of chronic diseases ... is expected to boost the market growth, as 3D bioprinting ... --> 3D bioprinting market is expected to reach ... by Grand View Research Inc. Rising prevalence of chronic diseases ...
(Date:11/26/2015)... --> ... att använda SyMRI för att hitta optimal ... med multipel skleros (MS) eller hjärntumörmetastaser och ... för att kunna använda SyMRI Research Edition ... kan man generera flera konstrastbilder från en ...
Breaking Medicine Technology: