Drugs may cause addiction by ‘remodelling’ brain

New evidence that addiction may be the result of hijacked neurobiological learning mechanisms:

…In experiments carried out on rats, a team of American researchers at Brown University in Rhode Island showed that even a single dose of morphine physically altered the neural pathways that regulate the sensation of craving.

The change persisted long after the effects of the drug had worn off.

The study, published in the British journal Nature, adds weight to a new theory that sees addiction as a disease which “remodels” brain mechanisms related to learning and memory, the lead author, cellular physiologist Julie Kauer, said in an interview.

Kauer’s experiments focused on the activity of synapses, the connective junction between brain cells.

So-called excitatory synapses increase the flow of chemicals — such as dopamine, associated with a feeling of euphoria — while inhibitory synapses impede such flows.

“You have to have both, because they create checks and balances on the system,” she explained.

Previous studies have shown that excitatory synapses are strongly linked to building one’s capacity for memory, and that — just like muscles in the body — they grow stronger over time with increased activity.

This is a virtuous circle when it comes to learning because the release of small amounts of dopamine creates the incentive to learn more. It also helps hone basic survival instincts.

But the same mechanism becomes a dangerous magnet for abuse when certain drugs such as heroin and cocaine provoke a similar response.

“If you have ever been really, really thirsty, that same craving may be the same thing that is going on in the brain of someone who is addicted to a drug,” Kauer said.

In this context, she added, “addiction is a form of pathological learning” in which the brain has created a rewards system for something that is harmful to the body.

The Nature study breaks new ground in two areas. It presents the strongest evidence to date that inhibitory synapses are also capable of “long-term potentiation”, or LTP, the ability to strengthen and change over time.

And it showed that morphine, an opiate, continued to block LTP long after the drug was absent from the animal’s system.

“The fact that they are long lasting could be one of the reasons that the craving for drugs is so hard to conquer, and suggests that addictive drugs are producing persistent physical changes,” she said.

The study also points to the intriguing possibility of a pharmaceutical treatment to neutralize intense cravings, which could help those fighting addiction to resist the temptation of relapse.

It could likewise help prevent unwanted side effects of morphine in hospitals, where the opiate is frequently used as a painkiller.

2 thoughts on “Drugs may cause addiction by ‘remodelling’ brain

  1. I found this article yesterday as well. I thought it was pretty interesting, but also a little scary. It seems to indicate that the wreckage caused by opiate use can’t be undone…

  2. I KNOW for a fact that daily opiate and Xanax use drastically changed me. I used them exactly as prescribed unitl March 06. Since then..well..read my story. I think I will NEVER recover and no one cares. I know now, looking back..depersonalization led me to totally disconnect from everyone and everything around me. Also..horrid insurance and no real realistic choices (or time needed) are lending to my slow,agonizing death. I am someone who is always in pain and is now physically addicted to both Oxycontin (8 years) and Xanax (21 years.) IN addition I have numerous chronic health problems ~ such as pulmonary fibrosis (thought to be MAC related although I am HIV -), Hep C , prior TIA, prior hypertension, depression, etc. I also KNOW I am dying. I am now 106 lbs and 5’9. (I weighed 243 lbs for about 8 yrs or so prior to Jan. 06.) I am in my early 50’s.I have horrid insurance (Med. & Medicaid) and no car, nor do I know anyone with a car.I have only been outside 5 times since Jan 06 as well…one of those trips to my PCP who in hindsight “dumped me” by telling me he was afraid I was dying and told me to go find a big hospital in the city who took NIH funding. He then added that his pratice and all of his referall specialists loathed and did not take my “new” secondary insurance due to the Medicare Advantage fiasco that occured abruptly for dual-eligibles in my state in Jan. O6. I told him our car was dying as well and he reminded me there was no public or medical transportation anyway. [I had moved in Sept. 05 from a quiet middle-class county to the nearby “budget busted” big city.] He was correct as I called every specialist and none took my secondary and confirmed by phone that the trans. was in-city only. In July of 06 ,I know..(the worst time possible) I did go to “supposedly” one of the TOP 10 hospitals in my state that got a LOT of NIH funding as my PCP suggested. I was admitted but they were at 110% capacity. I was only kept 2.5 days (1.5 of it in the ER) and the care was ~to be kind ~ “frenetic.” I rarely saw a nurse and if I did..I was spoken at, not to. I was healthier then and 167 lbs. (Although I had lost over 70 lbs. in 7 months.) My addiction(s) were not as bad as they are now. Then I was only taking 5 Xanax daily. They discovered the pulmonary nodules.I actually ended up begging the brand new attending (who always appeared very frustrated and overworked)to be allowed to stay but was abruptly discharged at 4 PM on a Friday anyway..never seeing their “promised” social worker or recieving any coherent follow-up care. I had wrote up a list of questions but the “team” was always in a hurry and rushing in and out. I never could get any of them to answer or even look at my papers.My PCP’s office staff messed up the OP referrals 3 times and then refused to try again. TO be fair.the OP ref.’s were done by a brand new resident and were not done correctly. She set me up with clinic appointments with “more brand new residents” (instead of putting down an actual hospital doctor) so the coding was somehow meaningless or non-existant. Neither the hospital nor my old PCP would call each other and I got lost in the middle. After 10 months or so of trying to get some type of home care, psych care, transportation or to find a new PCP who would accept both my insurances (which I never could), I gave up. Even attempting to just get basic correct information from this “new wretchedly thrown together” MedAdv. Plan was so ludicrous..I stopped calling out of frustration. They “outsource” their MH/D&A to a state 15 hours away who have no knowledge of this area. Temps constantly would answer the phones at the new MedAv and make things up. Supervisors were always too busy to come to the phone,etc. As for my secondary insurance..the welfare office knew nothing as far as docs who accepted it. The state said to call my local welfare office…they knew everything. The welfare office said to call the state back. I could go on and on. It was and still is disheartening and unorganized! Now 9 months later,I can barely stand more than 2 minutes at a time , nor can I perform any ADL’s. Sadly, I also have no family or friends except my grown son who is also an addict. Chronic constipation is so bad, I literally have to bite on a washcloth to prevent screaming from URQ back pain attempting to defecate, so I rarely eat and a decubitus ulcer is surely next as I am skin and bones. All my hair has fallen out and I have no one to bathe me. (My son does not know how to care take at all.) Always alone and never able to sleep or lie in any position for too long w/o pressure from being so frail -my Xanax use has spun wildly out of control. For 20 years I had always taken it as directed. I am dehydrated and void about 2 ounces a day if I am lucky. I never did have good veins from previous hospitalizations..so I have daily nightmares of having to go to an ER that is probably already short staffed and having to beg to be throughly washed first. ( I know I would most likely need a central line and ding ding.instant infection.)I KNOW I WOULD BE ANY ER DOC’s WORST NIGHTMARE. I read these blogs and all the doctors and nurses write about these days is money. [Or your dislike of Medicare/Medicaid/problematic patients.] I read too much..to the point that I suffer daily rather than even attempt to go to an ER again. The thought that I would not be believed or either just detoxed way too quickly or just right off of 20 Xanax 0.5 a day [and around 80 mg. of Oxycontin] is worse than dying this way. Or how do you do a colonoscopy or bronchoscopy on someone so addicted? Why is everything pushed toward outpatient when I have no one to help me at home? Would I be rushed out the door of any hospital or dumped to some horrendous nursing home in a ghetto (my insurance IS that bad) with roaches and most certainly undertrained, understaffed and most likely uncaring staff?I called the three lone drug detox’s in my area that even take my insurance and as expected, they are located in the worst neighborhoods imaginable. You get 3 to a maximum 7 days if you are lucky. Their protocols are “horrendous” according to guidelines supported by the better tx centers, 300 page addiction treatment protocol commission reports I have read or the recent HBO’s “Addiction Series” board’s guides and choices information [geared obviously for people who can afford to choose.] I am way too sick now to even walk..let alone attend groups or be in a facility with no truama hospital staff. My seizure risk would be so high even 30-90 days out if I did not go totally insane from “reverse anxiety” first from the Xanax WD alone. Also, having read extensively on addiction I know that a 3 or 7 day program in my condition would or could not work…esp. with no family, friends or transportation for aftercare. I can not even walk more than 10 feet now without getting severely lightheaded. I believe my abilty to even be this cognizant after 16 months of almost total isolation [except the 4 hours or so daily I see my son] speaks to the things I have not yet lost..my high level of intrinsic intelligence, acute awareness of the current state of mind of physicians and the grave disparities in medical care that sadly exist today and my own knowledge of my personally difficult medical and psychological condition(s).I KNOW that you all appear to categorize everyone who uses drugs or deteriorates like I have as “non-entities” or not worth treating. In reality I was and in many ways still am a warm and caring person. I am also very sensitive…which makes the thought of being “hated upon sight” or “judged harshly” even worse than suffering daily this way. I DO suffer. SS for writing so much.. I just wanted to REMIND everyone here that not all people are drug seekers ( I have a safe full)..some of us are also very ill and have an ounce of pride left. That pride
    I retain inside somewhere (coupled with shame and guilt) keep some of us upon reading all of these blogs and articles from even attempting to seek care. I don’t know why I am still alive but I certainly hope it ends soon. I see no way with the way medicine is structured now how I could have ANY realistic chance [or even be alotted the necessary timeframe it would take] at this severe point in my med history to recover.

Comments are closed.