A New Approach to Understanding Depression
Highlights
Even though sadness is a natural part of the human experience, the feelings of sadness or depression are short-lived. In the case of major depressive disorder (MDD), also known as clinical depression, such feelings intensify and persist for extended periods of time. MDD is a medical condition that impacts not only mood, but behaviour and physical function and can affect your quality of life in various ways, including appetite and sleep. Symptoms that can affect physical function include
· fatigue or consistent low energy
· decrease pain tolerance
· back pain or full body muscle aches
· headaches
· eye problems or decreasing vision
· stomach pain or abdominal uneasiness
· digestive problems including irregular bowel schedule
MDD hurts the affected individual and their families causing significant suffering and impairment, as well as substantial social costs.
To date, psychological models have focused primarily on well documented cognitive and interpersonal factors; but recent studies and accumulating evidence from basic research has shifted the focus on the role of bodily processes as the etiology in MDD. Specifically, motor displays affect emotional processes was documented in a meta-analysis of over 70 studies that manipulated motor displays in non-clinical participants. The results of the meta-analysis showed robust differences between poor posture (e.g., slumped posture, sad gait pattern) and expansive posture (e.g., upright posture); based on the context, types of manipulation and measurement methods, results included affective responses (e.g., power feeling, mood) and overt behaviour (e.g., risk taking). Likewise, a subset studies that involved a condition with neutral motor display indicated the effects are determined by the absence of contractive motor displays instead of the presence of expansive displays.
Studies indicate the role of the motoric system in MDD have shown the association between depression and slumped posture, with prominence in anterior head incline and thoracic kyphosis, and alterations in gait pattern. Even more interesting, the first experimental studies documented causal effects on depression-related processes with changing motor displays. In two studies, the effects of short motor manipulations on memory bias in MDD indicated non-depressed individuals show a positive bias, recalling more positive information than negative. The negative memory bias was one of major findings on cognitive processes in MDD. Empirical studies have shown that a biased memory predicts the symptoms of depression.
In a study by Michalak et al., participants sat in a slumped position or in an upright position while visualizing themselves in connection with positive or depression-related words. Then a distractor task along with an incident recall test of the words was conducted. Patients with an upright sitting posture showed an unbiased recall of positive and negative words; and patients sitting in a slumped position showed a biased recall of negative words characteristic of depressed individuals. Thus, the experiment showed changing the sitting posture of individuals with MDD affected the negative bias information.
In another study by Michalak et al., the effects of motor manipulations on memory bias were studied. When MDD participants performed either an upward-opening Qi Gong movement or a downward-closing Qi Gong movement, along with an incident recall using cue words, the results showed that individuals in the upward-opening position showed positive bias recall of affective words than those individuals in the downward-closing position. In addition, the effects of movement on overgeneralization autobiographical memories. What they found in the study was that when depressed individuals referred to a memory in a particular place and time, they overgeneralized their memories rather than specific moments particular to them. The stable cognitive characteristic of a depressed individual is reflected in an overgeneralized memory. Those individuals in an upward-opening position along with a more positive bias memory had a decrease in reporting overgeneralized autobiographical memories. The findings from the above-noted studies, along with the understanding of cognitive and interpersonal factors of MDD, showed motoric manipulations also affect emotional processes of MDD sufferers, and support the theory from the Interacting Cognitive Subsystems of the relevance of the body in depression. They propose that proprioceptive and kinesthetic input from the body has a direct and important contribution when processing emotional information. When depressed, a bodily and cognitive feedback loop is established “locking” the subsystem into a self-cycling configuration to perpetuate depression. In essence, depressive cognition leads to negative body displays which in turn feeds the increase in negative thoughts causing the vicious cycle to continue. It is important to note the effects from studies in basic research and clinical research dealt with short manipulations of motor displays.
Present research
Current research focuses on the myofascial system, a multi-dimensional continuum of connective tissue that creates integration of the body as a whole, which is involved in body tension regulation and the etiology of pathologies like chronic pain. What is fascinating about today’s research is the knowledge that fascial tissue contains contractile elements that play a role in modulating force and mechanosensory fine-tuning; fascial stiffness is influenced by biochemical as well as biomechanical processes; and contractile activity is biochemically directed with the presence of various cytokines of the extracellular matrix, including TGF-β1 that has been documented to influence the autonomous nervous system. Therefore, stress-related dysregulations of the autonomous nervous system and dysfunctions of the immune system that includes elevated TGF-β1 including effects on fascial contractile activity are expected to present as stiffness and decreased elasticity in individuals with MDD.
We expect not only the biochemical pathway to be affected, but also the biomechanical pathway resulting from dysfunction of the myofascial tissue in MDD. Individuals often show increased anterior head inclination and thoracic kyphosis with a slumped posture. This coincidentally aligns with the flexionrelaxation phenomenon, and the mechanical loading of the posterior passive connective tissues is associated with such postural changes. As such, we expect individuals with MDD should present with increased stiffness and reduced myofascial elasticity in the neck & upper back. Even though such posture is related to a protective biological response, the chronic stress connected with MDD will present as an upsurge of stiffness and reduced elasticity. To test the associated changes in myofascial tissue related to postural changes discussed in MDD, Study 1 compared upper back & neck stiffness and elasticity of the myofascial tissue from individuals with MDD against a non-depressed control group.
Additionally, assuming myofascial tissue and postural changes in the upper back and neck region might be a part of the depressive interlock configuration as postulated by the Interacting Cognitive Subsystem framework, then a chronic state of the tissue might be due to the ease of accessibility from proprioceptive input that repeatedly relays negative and depressed cognitive and emotional processes; thus, creating a self-perpetuating depression cycle. Study 2 focuses on the potential contribution of the myofascial tissue to the depression cycle based on analysis of the negative memory bias after self-myofascial release. Empirical studies have shown that negative emotionality and biased memory predict the course of depression symptoms.
Study 1
A total of 40 psychiatric inpatients were recruited into the study after meeting the criteria of the Diagnostic and Statistical Manual of Mental Disorder and scored greater than or equal to 14 on the Beck Depression Inventory. Additionally, 40 never depressed control participants were included and matched according to age, sex, and body-mass index. Twenty-five of the 40 participants had a comorbidity, anxiety disorder, diagnosed; while thirty-nine participants were prescribed antidepressant medication, primarily Serotonin-Reuptake Inhibitors or SerotoninNoradrenalin-Reuptake Inhibitors.
Conducting the study involved measuring stiffness and elasticity of myofascial tissue in the upper back and neck region with a total of four locations: right trapezius, left trapezius, right thoracic back, left thoracic back. Three assessments per location were completed using ETCM resistance with 30 second intervals at an 8mm depth. The use of the electronic tissue compliance meter (ETCM) provided a test-retest reliability of 0.84.
Study 1 Outcome
The results of Study 1 indicated depressed patients showed higher stiffness and reduced elasticity of the myofascial tissue. Long-term dysfunction in the tissue represented as stiffness and reduced elasticity may lead to intense chronic body tension and reduced suppleness of the motoric system. This may be a possible explanation for the characteristic reduced arm swing and slumped posture of a depressed individual. Factors of heightened body tension, depressed gait patterns and posture may act as a feedback loop in to the psychological system producing negative cognitions and emotional mindset. At this time, there is no information on dysfunction in the upper back and neck correlate with myofascial tissue in the rest of the body and whether stiffness and elasticity influence posture or gait. Future studies need to be carried out to supplement current findings. By carrying out further studies expanding the rest of the body and measuring stiffness and elasticity using sonography and sonoelastography, which can provide a more refined analysis of myofascial tissue, it is possible to clarify the influence of the different tissue layers, such as dermis, subcutaneous connective tissue, fascia profunda, and muscular layer, contribute to increased stiffness and decreased elasticity. Another avenue of research would question if stiffness and reduced elasticity is biomechanical – it is attributed to slumped posture of depressed individuals, or is it a biochemical process in myofascial tissue. Because Study 1 involved individuals under medication for anxiety disorders, additional studies could include samples without medication and comorbid anxiety disorders.
Study 2
Study 2 involved intervention targeting myofascial tissue to explain the possibility that myofascial tissue is involved in a depressive interlock configuration that makes negative and depressogenic cognitive and emotional processes more accessible. Sixty-nine patients with MDD were randomized either to a single-session self-myofascial release intervention (SMRI) or a placebo control intervention (PI) so that condition and effects of the intervention on psychological factors involved in the maintenance of depression were investigated. Analysis for a MANOVA confirmed the sample size was large enough with a Type I error rate of 0.05 and Type II error rate of 0.80. Inclusion and exclusion criteria were matching to that of Study 1. Comorbid diagnoses of primarily anxiety disorders were among 68% of the participants and 80% of those individuals were receiving antidepressant medication as treatment.
Participants completed the task in three phases:
1. they watched a short instruction video for neck and back exercises.
2. they practiced the neck and back exercises for 30 seconds, while lying on an exercise mat, using a foam roller and guided using audio instruction.
3. the exercises were completed individually without audio instructions, with neck and back exercises being completed 2x for 60 second with 90 second relaxation period along with self referential using positive and negative words.
Upon completion of exercises, participants remained resting on the mat while a Positive and Negative Affect Schedule (PANAS) was administered via video and verbal responses recorded.
Effects of SMRI in Study 2
Intervention focused on myofascial tissue affected memory bias in depressed individuals, but it did not take into account the level of physical activity in its participants. Individuals in the SMRI recalled fewer negative words and had a more positive affect than the PI group. Pain levels were higher during SMRI than PI. Participants in the SMRI, compared to the PI group, recalled few negative words and recalled more positive words. Surprisingly, controlling pain did not change the pattern of results and thus, did not affect the results. It was also observed that the effects of SMRI in depressed participants had a more positive mood than the control group. Again, controlling pain did not change the pattern of results. A remarkable outcome since SMRI induced more pain, but produced more positive affective outcomes. Other research studies have shown SMRI impacts the functional characteristics of myofascial tissue, thus, it can be deduced that increased elasticity and reduced stiffness in the tissue might be responsible for affective outcomes by way of somato-sensory input, producing more positive memory processing and a more positive emotional state. In turn, this decreases the depressive mind-body interlock. It may be that a decrease in elasticity and the presence of stiffness is associated with danger and stress.
The study did not directly measure the characteristics of fascial tissue. However, it has been documented that there is a short-term reduction in stiffness in response to self-myofascial treatment in back muscles of sedentary office workers resulting in a reduction in elasticity of the upper trapezius and corresponding paraspinals. In contrast, studies on foam rolling on the upper leg showed either no change or mixed results in stiffness changes. Further research is needed to determine what body regions induce biomechanical change in myofascial tissue and under what conditions with self-myofascial release treatment.
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