|Dr Nora Volkow|
|Dr Vibeke Amussen Frank|
The third day of Mind & Life XXVII - Dr Laura Volkow talks about The Role of Dopamine in the Addicted Human Brain and Dr Vibeke Amussen Frank follows with Beyond the Individual: The Role of Society and Culture in Addiction.
Day 3 AM - Nora Volkow
The Role of Dopamine in the Addicted Human Brain
Dr Volkow sees addiction as that point where a person has lost the ability to exert control over their desires and emotions, and the Buddhist tradition tries to achieve exactly the opposite. She discussed the criminalisation of drug use, and her commitment to help those addicted to drugs so they don't end up in prison. She explained how imaging techniques gave us the opportunity to see the brain and the effects of addiction on it. By collecting this knowledge we will be able to provide targeted interventions. Dr Volkow gave a brief overview of positron emission tomography (PET).
Dr Volkow spoke about the common reward pathway of drugs of abuse, and how all drugs had an effect on dopamine. She explained that 'reward' is an inclusive phrase, but that the experiences may be different. I will not go into detail about this here. She described addiction as a disease of learning.
One of the critical points that Dr Volkow made was that dopamine release was not consistent across all people, and this variability made some people more vulnerable than others to drug addiction. She explained how they expected those who were addicted to drugs to have large dopamine responses, or larger reward. What they found was the opposite. In detoxified cocaine addicts (3 weeks) when given Methylphenidate, they had approximately half the response when compared to the control group.
|Images from Volkow's research (not the same images as used in her presentation)|
Dr Volkow explained that one hypothesis is that there is a down regulation, and thus natural rewards become "less rewarding". This is presumed to happen after repeated use of the drug. In experimentation they found an attenuation of the system of motivation. She then explained Pavlov's experiments and the principles of classical conditioning, and how they are able to now measure dopamine in relation to these experiments. Basically it was found that conditioned stimuli increased the levels of dopamine. This is very important because it is at this point that attention is focused and motivation for receiving the reward gets established.
When you get rapid increases in dopamine, this helps create stronger memories. The hippocampus and amygdala send projections to the nucleus accumbens, so these memories cause motivated behaviour. Images of drug cues have been shown to increase levels of dopamine in addicted individuals, and this leads to craving. The larger the increases dopamine, the greater the increase in craving. Dr Volkow made a vital point: The reward system of the consumption is attenuated, while the expectation of the reward is sensitized or heightened.
Dr Volkow described how they were looking effects on the frontal cortex. The question is "are the changes in dopamine a function in addicted subjects linked with disruption of frontal activity?" It was shown that dopamine D2 receptors are lower in addiction across all drugs. She stressed, however, that there is significant variability. Low levels of D2 receptors is NOT enough to explain addiction. She suggested that perhaps a medication that increased D2 receptors may help, and would, if worked, prove causality. Or, as Richard Davidson suggested, and for me intriguingly, we could develop behavioural interventions. She explained how animal experiments had been done through gene therapy.
D1 and D2 (there are 5 DA receptors) are very important in addiction (see Kent Berridge's talk). If you upgrade D1 receptors you would enhances the rewarding effects of drugs. D2 decreases them, if you decrease D2 it makes you vulnerable, but an increase is protective. In addiction we see a decrease in D2 receptors.
Dr Volkow moved on to describing the glucose metabolism in the frontal cortex. There are decreases of D2 receptors in the orbito frontal cortex and anterior cingulate girrus, and this lowers metabolism. What are the consequences, Dr Volkow asks. Well, they are complex and many. The anterior cingulate girrus allows us to detect discordance. If this does not operate properly, we are less able to spot inconstancy or errors. The orbito frontal cortex attributes importance or present salience to an object or behaviour. There develops a rigidity and inflexibility. This is similar to OCD. There is often a continuation of use and behaviour in spite of the loss of reward.
There develops a perseverance of the behaviours without mediation by the frontal cortex. There is a loss of integration of the levels of consciousness. She spoke of addiction as being part of a behavioural continuum. Dr Volkow spoke of the default mode network, and we are able to shift between conscious and unconscious modes. This can be lost, and the default mode network can become "hyper-engaged".
There was then a discussion, at some length, about what can and can't be seen through brain scans, for example compassion, or sensory pain, or craving. Dr Volkow explained that she was able to see craving from brain imaging.
Dr Volkow spoke about genetic variability and vulnerability, which is estimated at about 50%. She spoke about the importance of childhood stressors as factors in developing a vulnerability. The levels of D2 receptors were found not to be inherited by the children of alcoholics. There was compensation through increased receptor level and activity in the PFC.
Dr Volkow then showed the same diagram as had been shown by Dr Davidson, and explained how the addict brain is affected:
The amygdala has the ability of disconnecting the PFC. There is a positive feedback loop that develops.
Dr Volkow believes that there needs to be a multiprong approach to treating addictive disorders. NIDA are funding research into various interventions, and that possibly pharmacology could help focus on the intervention in a temporary way. She spoke of a meditation/mindfulness intervention for smokers where without even discussing the intended outcomes, smoking was reduced. There is a computer program that helps give biofeedback to help train the frontal cortex to override the amygdala. Another intervention strengthens the power of non-drug stimulation, for example spiritual interventions which provide a "richness of life".
Dr Volkow showed a painting by Gustafson that she feels captures the "poverty yet intensity" of the addictive experience. Unfortunately I cannot find this painting on the web, but it can be seen at 1:48:58 on the video.
Her talk ended there.
Day 3 PM - Vibeke Asmussen Frank
Beyond the Individual: The Role of Society and Culture in Addiction.
Dr Frank is a social anthropologist. She explained that her main interest is how people live with substances, whay and when they use them and the context and social practices with them. Here overall perspective is:
- relationships between individuals and the dynamics between the individual and the psycho-social context.
- Processes in and out of substance use and addiction from a relational perspective.
- How the substance is experienced by individuals.
- Ways out of problematic substance use, looking at treatment efficacy and self-change
- Regulating substances, which in itself can in itself cause harm.
Dr Frank described treatment according to Blomquists definition " Any kind of structured intervention, either medical or psychosocial or a combination of both." She discussed the various forms of treatment briefly. Dr Frank showed how between the 70s and 2011we have seen limited improvements in treatment efficacy.
If we ask patients as to why they seek treatment, it is often so they can control drug use or pause from the lifestyle, and as such the goals may differ from the treatment provider. She spoke how the close monitoring of substitution therapies may actually deter people from seeking treatment. Structural conditions may also affect motivations to stay in or out of treatment, such as the potential loss of social networks. Perhaps the an option would be to shift the focus from compliance to treatments concordance with everyday life and thereby reduce the internal dilema.
Dr Frank then moved to self-change as a mode of recovery. She quoted figures for alcohol use and remission via self-change. People with less problems related to the DSM criteria were more likely to remit than those with multiple problems.
What are the reasons to start and maintain self-change?
- Positive life circumstances
- Social influences
- Health concerns
- Change in perception of substance use
- Both sudden or planned decisions were made
- public policy
- health policy
- prevention policy
- control policy
- Addiction is experienced by individuals who are embedded in social and cultural settings
- Not only the way substances are used, but also the way societies control and regulate substances causes harm.
The session then ended.