Dual-process Models and Addiction
There is an article that makes interesting reading in the Clinical Psychological Science Journal entitled Cognitive Bias Modification and Cognitive Control Training in Addiction and Related Psychopathology: Mechanisma, Clinical Perspectives and Ways Forward. It examines arguments against and support for dual-process models, using the metaphor of the rider and horse. The horse being impulsive processes and the rider representing the more top-down reflective processes.The article goes on to examine how each of these dual processes can be modified through targeted training. When taken in the context of current findings in neurobiology the dual-process model, can, I feel, provide some good directions for effective addiction treatment. I have certainly found that both the rider and the horse, to extend the metaphor, need work!
Therapy Ineffective for Opioid Addiction?
The news from around the world has been filled with a variety of articles about drug policy. Sam Branson (Richard's son) released the film "Breaking the Taboo", which focuses on the harm done by and the ending of the Global War on Drugs. Because of this there has been renewed coverage of the Drug Policy Alliance. This group has the support of such luminaries as Sir Richard Branson, George Soros, Former Surgeon General Joycelyn Elders, a number of former presidents and political leaders....oh, and Sting. Their mission is "advance those policies and attitudes that best reduce the harms of both drug use and drug prohibition, and to promote the sovereignty of individuals over their minds and bodies."
|Illustration by Norma Bar|
Across the pond in the United Kingdom the UK Drug Policy Commission wrapped up 5 years of work and published their final report: A Fresh Approach to Drugs. Arguably the most important recommendation is that the political lead for national drug policy be moved from the Home Office to the Department of Health.This recommendation is embraced by the British Medical Association who are encouraging their members to join the debate on drugs policy.
In amongst all of this I found this article about a program in Seattle that seems to be working, and I really think this LEAD program has some really good points. Basically it enables Police officers to divert those arrested on possession charges directly into housing and treatment facilities, by-passing the criminal justice system. I first read about it in the Seattle Times, and took a look at the LEAD website. There is also a short concept paper. There is great potential in this project, and perhaps it is small projects like these that will change the hearts and minds of the people and result in more effective public policy.
Meth Psychosis Confirmed in Study
A recent study published in JAMA Psychiatry confirms what many of us in the Western Cape already know: Meth use causes psychosis. The lead author, Dr Rebecca McKetin studied 278 meth users in Australia. She observed their meth use and psychotic behaviours over a period of 4 years, and the study concludes that Meth use significantly increases incidence of psychosis - 27% likelihood for those that use 1-15 times a month and a massive 48% for those who use16 or more times. Across the board, the chances of having a psychotic episode increased 5 times with Meth use. This particular study listed pre-existing psychotic episodes as an exclusion criteria, so it would appear that Meth may actually cause the psychosis rather than catalyze a pre-existing condition. As Dr McKetin says: "I think this is probably as close as we're going to get to showing a causal relationship between methamphetamine use and psychotic symptoms. There's actually quite a lot of evidence when taken together that suggests that that is the case." Also important to note was that when combined with heavy cannabis and alcohol use psychosis was seen in 69% of the cases.
Transcriptional Mechanisms of Drug Addiction
In his article, Transcription Mechanisms of Drug Addiction, Eric Nestler briefly reviews the growing evidence for the role played by prominent transcription factors in gene expression in addiction. This is an area of particular interest because, in my mind, it is these transcription factors that may affect gene expression that leads to the long-term effects of addiction even after extended abstinence. In this article Nestler discusses Nuclear Factor Kappa B, cAMP and Delta-Fos B. Delta-Fos B has long been linked with the development of spiny neurons in cocaine addicts, but what Nestler doesn't discuss or explain is the increases we see in Delta-Fos B in behavioural addictions. Could it be that increases in Delta Fos-B are not the result of the drug action, but as a result of some internal mechanism that results from addictive behaviour? Could the levels of Delta Fos B perhaps be the biological marker for the move from user to addict? More research is needed to examine the transcription factors in behavioural addictions before we can answer these questions.
A little further down the cAMP line we find CREB (cAMP response element-binding protein). The upregulation of CREB is thought to contribute to the tolerence and withdrawal states of addiction through increased dynorphine transmission.. Elevated levels of CREB in the NAc of rats seem to make the rats less sensitive to the rewarding effects of cocaine. It is thought that further investigation may lead to the development of pharmaco-therapies for stimulants. You can read more about this in the paper Roles of Nucleus Accumbens CREB and Dynorphine in Dysregulation of Motivation.
If you have no idea what any of this is about you may want to read my essay The Neurobiological Underpinnings of Addiction.
Nepicastat Clinical Trials Target Relapse
Some of us may be familiar with the work of Berridge, Robinson, Steketee, Kalivas and others in the area of long-term sensitisation of addicts to stress, drug cues and the drug itself, which can lead to the reinstatement of drug seeking behaviours even after long-term abstinence. It is proposed that by inhibiting the enzyme dopamine beta-hydroxylase and lowering norepinephrine levels, the desire to reinstate drug seeking behaviour may be reduced. Pre-clinical trials have shown that Nepicastat doesn't stop rats from administering a steady stream of cocaine, but it does reduce reinstatement after a break, and they do not work as hard to get cocaine when exposed to stress or drug related cues. Interestingly it does not seem to stem their desire for other behaviours, such as getting food or sugar. The double blind clinical trials are being sponsored by NIDA.
18-MC Trials Target Reward System in Addiction and Obesity
Personality of the Month
Marc is a developmental neuroscientist and professor of developmental psychology, recently at the University of Toronto. He is currently at Radbound University in the Netherlands. He has authored over 50 journal articles in psychology and neuroscience. The reason, however, I have decided to feature Marc is because of his personal history of addiction which is documented in his book and his amazing blog, Memoirs of an Addicted Brain.. This blog has some really fascinating posts that stimulate all sorts of conversation, and the comments are of a far higher standard than we usually see on the web. Marc also makes the effort of responding to many of the comments and he also has a guest memoirs section. Reading these memoirs and Marc's blog brings home the fact that addiction affects all walks of life and that these are people we are dealing with. And that neatly brings me to this month's quotes:
Quotes of the month:
Lee Hoffer criticizes the "overly quantitative presentations on the "behaviors" of drug users that dominate conferences in the field" in his article Unreal Models of Real Behaviour: The Agent-Based Modeling Experience. He goes on to say:
"The highly personal narratives of participants framed by equally complex social environments are not visible in the numbers. To epidemiologists and other like-minded health researchers, the numbers are the narrative and all that is required for informing and evaluating theories, models, interventions, treatment programs, or policy."And if that isn't enough for the scientists among us to take things personally, in his article titled Too many rating Scales: Not enough Validation published in the December 26 issue of Addiction, Duncan Raistrick says:
“Experts and stakeholders are, by definition, selected because they are distinguished in their field, and have opinions and experience to bring to the table. The problem is that opinions are often very strongly held to the exclusion of equally strong science"
Dr Frankenstein's School of Ablative Surgery
Forget the pharmacological approach, let's just get in there and "vaporize" the nucleus accumbens. For those of you who haven't studied the dark arts, the procedure involves drilling a couple of holes in the skull and inserting long electrodes into the "pleasure center" of the brain. An electrical current is then passed through the electrodes which kills the cells in the nucleus accumbens. A recent paper published in Stereotactic and Functional Neurosurgery reports that 60 opioid addicted patients in mainland China were followed up 5 years after surgery. and 47,4% were seen to be abstinent.On the other side of the coin, memory deficits were seen in 21%, motivational loss in 18% and some changes in personality in 53%. In spite of this the paper concludes: "The bilateral ablation of NAc by stereotactic neurosurgery was a feasible method for alleviating psychological dependence on opiate drugs and preventing a relapse. Long-term follow-up suggested that surgery can improve the personality and psychopathological profile of opiate addicts with a trend towards normal levels, provided persistent abstinence can be maintained; relapse, on the other hand, may ruin this effect.". Hopefully they wont use the same technique to cure my skepticism.
Those of you who are excited by the prospect of ablative surgery may also derive some pleasure out of the cure described in the Siberian Times (where else): Dr German Pilipenko and Professor Marina Chukhrova believe that their "limited pain exposure" method of treating addictions stimulates the brain to produce endorphins, thereby "making patients happier in their skins". The amazing thing about this "cure" is that it apparently treats depression and obsessions as well. Natasha, one of the success stories says: "I wouldn't keep coming back for this if I didn't think it was working. I know many of my friends think I am mad to trust these doctors. But I want to live. For the first time since I because an addict five years ago, I feel I have a chance. I just want to be like all those thousands of girls who have a normal life - finding a man, getting married, having kids, going through the problems of life together. I want that kind of normal life - and finally I can feel I am coming back to it." Maybe in Siberia a "normal" life involves having the crap hit out of you.