While reading “Addiction and the Treatment of Pain” written by P. Ziegler, I realized one potential my experiment could have to help addicts. Most pain medications are opiate based, and these medications, while useful, can trigger relapse or new addictions in addicts. For this reason it is important to find alternatives to treat pain in addicts. I hypothesize that addicts might be able to harness the focus they use on their addiction to become less sensitive to pain.
The article “What Imaging Teaches Us About Pain” by Elizabeth Church was very informative to me.
First, it describes pain. As much as we may hate pain and avoid it at all costs, pain is actually a good thing. It is “an alarm system that protects individual organisms from potential or actual physical threats.” It is a complex sensory and emotional experience that warns us if there is potential or actual damage to us, or if something is just wrong. One type of pain described is nociception, which is the activation of nerve endings that respond differently to tissue-damaging stimuli. The activation of these nerve endings may or may not be perceived as pain. Pain is actually a very subjective experience. Our experience of pain is completely dependent on our interpretation of it. It is colored by our belief about the pain, our expectations, and our mood. Our perceptions may or may not match with the nociceptive input. Basically, our pain is fueled by our mind.
However, biology comes into play as well with genetic factors that influence the experience of pain. There are even specific neurotransmitters in the forebrain that are involved with the reduction of the intensity of the pain experience. The pain matrix is a large network that becomes activated during the nociceptive processing. What is interesting is that individuals have different portions of the central nervous system that play different roles in pain processing in this pain network. To get into some hard biology, there are common regions of the brain that are involved in pain processing. These include the sensory-discriminatory areas of the central nervous system, which are the parietal lobe of the cerebral cortex, including the primary somatosensory (sense of touch), secondary somatosensory, thalamus (relays sensory information), and posterior portions of the insula (linked to regulation of emotion and homeostasis, perception, motor control, self awareness, and cognitive functioning). Also, areas of the brain associated with cognition and affect (anterior portions of the insula, the anterior cingulated cortex, and the prefrontal cortex) help regulate pain.
As far as I can see, a lot of pain processing is located in the brain. This means that neural imaging can be used to show pain intensity in an objective manner versus the normal participant evaluations that are subjective to their experiences. While an fMRI would be nice to use to an imaging tool, it seems a little bulky for my experimental design, so I think DOT diffuse optical tomography might work better. The participant wears a helmet with lights sources and detectors that absorb and respond to light, and by some scientific magic this detects changes in cerebral blood flow, which show areas of brain activity. I think that this method will be a nice addition to the subjective VAS scale I intend to include in my experimental design.
Another interesting point of this article was that the best alternative (non-medication) treatment of pain is meditation. Meditation overall can improve attention, relieve anxiety and depression, reduce anger and cortisol levels, and strengthen immune responses and gray matter density. While the benefits of meditation are numerous, I could never get past the boring part myself. Also, meditators had a lower pain sensitivity than control subjects. When faced with heat, it took higher temperatures before they felt any pain! The strength of this pain regulation depends on the amount of meditation experience, and unfortunately 2000 plus hours are needed for significant control of pain. Short term meditation does have some effect, though. I would love to contrast a meditator with a drug addict, because in a way addicts adhere to their own inner mantra.
I recently read “Effect of Brief Mindfulness Intervention on Tolerance and Distress of Pain Induced by Cold-Pressor Task” written by Xinghua Liu.
This article tested short term mindfulness meditation against distraction intervention on pain tolerance and pain intensity. The mindfulness intervention included increasing awareness to bodily sensations and objectively accepting these experiences. Mindfulness is accepting the pain rather than avoiding or fighting it. The distraction intervention, which in most studies is completing hard math problems, was imagining a happy scene. A distraction from the pain can lessen it. Surprisingly, there was no significant difference in pain tolerance and intensity between subjects who used the mindfulness method and those who used the distraction method. I was worried that, because mindfulness is negatively correlated with cravings and addiction and it is positively correlated with increased pain tolerance, addicts, who are not naturally mindful, will have a decreased pain tolerance. This article shows, however, that there are different ways to tolerate pain, distraction being just as effective as mindfulness. Even if the guided imaginings of the addicts are nothing like the process of meditation, I am interested to see if the repeated thought process involving addictions is similar to the distraction technique. It might be good to have a control group that uses the distraction technique in my project.
Additionally, I think I will use the Cold pressor test mentioned in this article to measure pain. The equipment is two plastic containers. One is filled with warm water that is 37 degrees Celsius and the other with cold water and ice that is kept around 2 degrees Celsius. To prevent the participants’ hands from touching the ice directly, the ice is wrapped in plastic and tucked away in a bottom corner of the container. First, the participants place one of their hands in the warm container for two minutes to establish a baseline temperature. Next, the participants move that same hand to the container that is cold. They simply keep their hand in the water until they cannot handle the pain anymore, in which case they remove their hand from the water. To prevent any damage to the hand, the maximum time limit is 5 minutes, but the participants are not told this. Immediately after the procedure, the participants rate their pain experience. This seems like a simple and effective design, and an overall good way to test what I am trying to measure.
The most important piece of information I gleamed from HC Fox’s article “Frequency of recent cocaine and alcohol use affects drug craving and associated responses to stress and drug-related cues” was the use of guided imagery. Guided imagery involves “re-living” a recent stressful or drug-related personal event through guided imagery and recall. I feel like this would be a good way to have the addicts in my study focus on their addiction before the pain test. Instead of just telling the addicts to think of their addiction, this method would be standardized and repeatable, meaning the participants would all be told to imagine the same scenario. It might be how they felt when they last indulged in their addiction, or imagining a scenario where they can indulge in their addiction all they want with no consequences. I want to try and mimic the obsession that comes with intense addiction, and focusing in this manner might work.
Also, I liked the statistic analyses that were performed. A linear mixed effect model is good when there are repeated measurements from the same individual. This could be good if I have the participants do the pain test with and without the independent variable. A T-test was performed, which is good to determine demographic and baseline drug differences. Both of these statistical models could be used in my study.
I recently read the article “Abnormal pain response in pain-sensitive opiate addicts after prolonged abstinence predicts increased drug craving” written by Ren Zhen-Yu. This article is a great foundation for what I want to write my research proposal on.
In the article, the different intensities of cravings of opiate addicts was related with how much pain was felt. Overall, the opiate addicts in this study showed a shorter tolerance for pain than control subjects, which is one of the reasons I have decided to use alcoholics instead of opiate addicts in my study. Opiate addicts can show either an increased tolerance to pain or a decreased tolerance to pain, depending on what stage of addiction the individual is in-development, maintenance, withdrawal periods, and periods of abstinence. This could be because opiates have a specific receptor in the brain, since our bodies can actually produce certain opiates (endorphins). Also, opiates such as morphine are used to treat pain directly. Additionally, people who are at risk for opiate addiction might already be partially intolerant of pain. They might choose to take opiates to relieve their pain. Our bodies cannot naturally produce alcohol, and alcohol does not directly affect pain receptors, so I feel like alcoholism will be a better substance disorder for me to test than opiate addiction.
I like the descriptions of the participants that were involved in the study. The opiate addicted participants had to be four months sober, could not be on any other psychoactive drugs except nicotine (so cigarettes are okay), any prescribed medicine, any medication for physical or mental disorders, and could not have a pain condition. The control patients had to have no history of substance abuse, pain conditions, serious physical or mental disorders, and not be on medication. To ensure this, a urine sample was taken to test for drugs. They were collected through word of mouth and advertisement. I feel like this will be a good model for me to follow.
A Cold pressor test (CPT) was used to test for tolerance to pain and pain intensity (sensory aspect) and distress (affective/emotional aspect). I really like this quote that was used to describe the difference between pain intensity and distress. “To understand the difference between pain intensity and distress, think of listening to music on a radio. As I turn the volume up, I can ask you how loud the music is or I can ask you how pleasant or unpleasant the music is to listen to. The intensity of pain is like the loudness of music. How pleasant or unpleasant the music is depends on how much you like or dislike the music, and the distress of pain depends on how much you dislike the sensation.” These levels were measure using separate visual analogue scales VAS 0-100, 0 being “not at all intense” or “not at all unpleasant” and 100 being “the most intense pain imaginable” or “the most unpleasant pain imaginable.” Again, this seems like a really good model for me to follow.