What’s new: cannabinoids, mindfulness, and the depression-arthritis connection.
References1. De Vita MJ, Moskal D, Maisto SA, et al. Association of cannabinoid administration with experimental pain in healthy adults: a systematic review and meta-analysis. JAMA Psychiatry. Published online September 19, 2018. doi:10.1001/jamapsychiatry.2018.2503.2. Zeidan F, Salomons T, Farris SR, et al. Neural mechanisms supporting the relationship between dispositional mindfulness and pain. Pain. 2018 Jul 12. doi: 10.1097/j.pain.0000000000001344.3. Brooks JM, Titus AJ, Polenick CA, et al. Prevalence rates of arthritis among US older adults with varying degrees of depression: findings from the 2011 to 2014 National Health and Nutrition Examination Survey. Int J Geriatr Psychiatry. 2018 Sep 19. doi: 10.1002/gps.4971.
Pain is often a subjective symptom. New research shows: (1) cannabinoids do not appear to reduce pain intensity but may make pain seem less unpleasant and more tolerable; (2) mindful people appear to feel less pain; and (3) more than half of older adults with mild depression experience arthritis pain.1-3 Scroll through the slides for the latest findings and their clinical implications.
Cannabinoid drugs may prevent the onset of pain by raising pain thresholds slightly but may not reduce the intensity of experimental pain already being experienced; instead, they may make the pain feel less unpleasant and more tolerable. A systematic review and meta-analysis of 18 placebo-controlled studies looking at the effect of plant-based or synthetic cannabinoids included 442 healthy adults.1 The search yielded sufficient data to analyze 18 pain threshold comparisons, 22 pain intensity comparisons, 9 pain unpleasantness comparisons, 13 pain tolerance comparisons, and 9 mechanical hyperalgesia comparisons.
Cannabinoid administration was associated with small increases in pain threshold, small to medium increases in pain tolerance, and a small to medium reduction in the unpleasantness of ongoing experimental pain. Cannabinoids were not reliably associated with a decrease in experimental pain intensity or mechanical hyperalgesia.
Clinical Implications: “What this means is that cannabinoid analgesia may be driven by an affective, rather than a sensory component. These findings have implications for understanding the analgesic properties of cannabinoids. The cumulative research synthesized in our review has helped characterize how cannabis and cannabinoids affect different dimensions of pain reactivity. It may underlie the widely held belief that cannabis relieves pain,” said lead author Martin J. De Vita of the department of psychology at Syracuse University in New York State.
The study included 76 healthy volunteers who had never meditated.2 First, they completed the Freiburg Mindfulness Inventory, a reliable clinical measurement of mindfulness, to determine their baseline levels. Then, while undergoing functional magnetic resonance imaging, they were administered painful heat stimulation (120°F).
The participants with higher mindfulness ratings had less activation in the central nodes (posterior cingulate cortex) of the default network, and they experienced less pain. Those with lower mindfulness ratings had greater activation of this part of the brain and felt more pain.
Clinical Implications: “Now we have some new ammunition to target this brain region in the development of effective pain therapies. Importantly, this work shows that we should consider one's level of mindfulness when calculating why and how one feels less or more pain. Based on our earlier research, we know we can increase mindfulness through relatively short periods of mindfulness meditation training, so this may prove to be an effective way to provide pain relief for the millions of people suffering from chronic pain,” said lead author Fadel Zeidan, PhD, assistant professor of neurobiology and anatomy at Wake Forest School of Medicine in Winston-Salem, NC.
Arthritis pain is highly prevalent among older adults who are depressed, which suggests that arthritis and depression need to be viewed as frequently co-occurring issues. An analysis included 2483 women and 2309 men (mean age, 64.5 years) who had participated in the National Health and Nutrition Examination Survey between 2011 and 2014.3 Nearly half (2094 participants) said they had a physician’s diagnosis of arthritis.
The prevalence of arthritis increased with the severity of depression. Prevalence was 55% in minor depression, 62.9% in moderate depression, and 67.8% in severe depression. A significant association was found between all forms of depression.
Clinical Implications: “Arthritis is commonly reported in participants with varying degrees of depression. This study highlights the importance of screening for and treating arthritisârelated pain in older adults with depressive symptoms,” said the researchers, led by Jessica M. Brooks, PhD, of the department of psychiatry at Dartmouth College in Hanover, NH. “It may be critical for mental health care providers to provide regular arthritis-related pain assessments and evidenceâbased treatments for coâoccurring arthritis in older adults with or at risk for depression.”