unseasoned adults who smoked marijuana every daylight for three yr during their teen years have an curiously shaped hippocampus and do poorly on tenacious - term memory board tasks , according to a newstudypublished inHippocampusthis week .
A team led byNorthwestern ’s Matthew Smithused MRI to map the brains of 97 participants : 44 sizeable controls , 10 subject with a history of marijuana use disorder , 28 dementia praecox patients with no history of meaning use disorders , and 15 dementia praecox patients with a marijuana use upset . Participants with preceding marijuana manipulation disorderliness were in their former twenty during the study and had stopped smoking pot for two year ; they all started using marijuana daily when they were between 16 and 17 years onetime for about three years .
All of the enlistee took a narration memory tryout designed to assess their ability to encode , store , and come back details from story . " The retention process that appear to be affected by cannabis are ones that we use every day to lick common problems and to suffer our relationships with friend and family , " study co - authorJohn Csernansky of Northwesternexplains in anews release . Previous work have join juvenile cannabis use with poor short - full term and working memory , as well as the abnormal conformation of sub - cortex structures . The hippocampus , on the other hand , play a primal role in longsighted - terminus ( or occasional ) memory — the ability to commemorate life events .
Compared with control , former substance abuser scored 18 percent defective on the long - term memory run , and the longer they used marijuana , the more abnormal their hippocampal shape appear . The change in shape likely reflects structural damage to the hippocampus and its neurons and axone . what is more , young adult with dementia praecox who abused ganja as teens performed about 26 percent more ill on memory test compare with young adults with schizophrenia who never smoke tidy sum .
The study only looks at one point in sentence , so a much longer field of study is ask to affirm marijuana ’s force on the brain and retentivity impairment . Anotherrecent MRI studywith marijuana users , for example , conk out to ascertain any departure in the volume in encephalon region , including the hippocampus . Additionally , " it is potential that the abnormal brain structures let on a pre - existing vulnerability to marijuana abuse,“Smith add . " But evidence that the longer the participants were abusing marijuana , the bully the departure in genus Hippocampus shape suggests marijuana may be the cause . "
