Are mindfulness exercises effective in reducing depression? A review

Ruma Mian, M.D.

Introduction 

Depression is not only the most common mental illness, it’s also one of the most tenacious. Epidemiologically, 50 percent of the population that experiences one major depressive episode will relapse and 80 percent will relapse after experiencing a second episode (1). Although anti-depressive medications may benefit some, a shocking number find them to be highly unfavorable treatment option due to their nagging side effects and poor health outcome. Identifying a non-pharmacological intervention such as mindfulness exercises can be a great development towards the treatment of depressed mood. In the simplest words, mindfulness is a non-judgmental practice of brining self-awareness to the present moment. In its therapeutic forms, mindfulness exercises promote increased acceptance of negative affect and offer enhanced well being. Cognitive neuroscience has begun to identify neural correlates of nonjudgmental, present moment attention and thought patterns associated with mindfulness-based interventions (2). During mindfulness exercises the mind is directed towards the limbic pathway for present-moment sensory awareness, involving the thalamus, insula, and primary sensory regions (3). In patients with affective disorders, mindfulness training acts as an alternative to control emotion. It instead, broadly directs attention towards monitoring fluctuations in the momentary experience. (2) While recent clinical studies have validated the efficacy of these interventions, our understanding of their mechanisms and the underlying adaptive affect regulation through practicing mindfulness remains ambivilent. This article demonstrates how some mindfulness exercises such as the Mindfulness Based Stress Reduction (MBSR) by Kabat Zinn can control neural pathways that regulate psychopathologies causing affect dysregulation such as depression.

Method

In order to answer my question I studied articles that correlated mindfulness with reducing depression using the following keywords: Mindfulness, depression. I found about 40 relevant articles in pubmed and selected five to include in my study.

Study 1: Mindfulness Versus Yoga: Effects on Depression and/or Anxiety in College Students

Objective: To study the effectiveness of the two different interventions, yoga and mindfulness and a non-interventional control group mitigating the effects of anxiety and depression in college students (4).

Independent variables: Yoga and mindfulness.

Dependent variables: Anxiety and depression.

Study Design: Randomized stratified control.

Method:  The study included 90 college students above the age of 18 years with a diagnosis of anxiety and depression. The students were randomly assigned to one of the three groups, one practicing the mindfulness intervention, the second practicing the yoga intervention and the third was the non-intervention group. The participants in the intervention groups attended an eight week course of either mindfulness or yoga. Their symptoms of stress, anxiety, depression, self-compassion and mindfulness were recorded at base-line and compared with conclusive reports. In addition the participants were asked to practice the interventions learned during the sessions outside of class for 20 minutes everyday. Inclusion criteria: All undergraduate students with anxiety or depression. Exclusion criteria: Students with personality disorders, thought disorders, substance abuse disorders or if attended more than four mindfulness sessions. The following scales were used: Beck Depression Inventory, the Hamilton Anxiety scale, Student Life Stress Inventory, the Self-Compassion Scale and the Cognitive and Affective Mindfulness Scale to assess the dependent variables in this study (4).

Results: Compared with the control group, depressive, anxiety and stress symptoms were significantly reduced in both the mindfulness and yoga group from pre to follow-up measurements. However self-compassion scores only increased in the mindfulness intervention group. It was also noted that scores continued to be significant through the follow-up measures for the BDI-II and HAS, the scores for these scales stayed the same from post to follow-up measurements in yoga group. The same trend followed for self-compassion assessment (4).

Conclusion: The study was enhanced by the inclusion of a control group design. There were a few limitations however. Firstly the sample size was small and mainly consisted of Caucasian undergraduate students which decreases generalizability. The data obtained was self reported therefore it is subject to recall bias. Future studies can be improved with a randomized sampling instead of a quasi-randomized sampling, a higher number of participants and a more diverse sample (4).

Study 2: Mindfulness and Coping Are Inversely Related to Psychiatric Symptoms in patients and informal Caregivers in the Neuroscience ICU: Implications for Clinical Care

Objective: To assess the correlation of psychosocial resiliency factors like mindfulness and coping with symptoms of PTSD, anxiety, depression in patients recently admitted to the neuroscience ICU and their primary informal caregivers (5).

Study design: Cross-sectional correlational study.

Independent variables: Mindfulness, coping, psychological resiliency.

Dependent variables: Psychiatric morbidity, depression, anxiety, posttraumatic stress.

Method: After 14 days of admission to the Neuroscience ICU, 81 patients and 92 care-givers completed the questionnaires for the study. The scales included: Posttraumatic Checklist Specific Stressor, The Hospital Anxiety and Depression scale, Cognitive and Affective mindfulness Scale which assessed the ability of a participant to experience the present moment, and Measure of Coping Status (5).

Results: Rates of clinically significant post-traumatic stress, anxiety and depression were high and equally prevalent among patients and caregivers within 2 weeks of hospitalization in the Neuro-ICU. For both of these groups high level of psychological resiliency through mindfulness was associated with lower psychiatric symptoms.

Psychosocial interventions though mindfulness and coping efficacy training may prove to be an effective and innovative way to ameliorate psychiatric morbidity and reduce suffering among vulnerable families presenting to the neuro-ICU (5).

Conclusion: The study had some limitations such as the fact subjects self reported the symptoms of anxiety, depression and trauma created self-report bias. Future studies should use objective methods of assessing distress by using clinical interview, chart review or psychoneuroimmuno/endocrinological markers. The other limitation was the fact that this study had a Cross sectional design which limits follow up over time. This misses the observation of psychiatric symptoms as the hospital admission progresses (5).

Study 3: Mindfulness Based Stress Reduction reduces Anxiety, Depression and Suicidal Ideation in Veterans

Purpose: This was a prospective study. The purpose of this study was to understand if MBSR reduces anxiety, depression and suicidal ideations in Veterans (6).

Independent variables: Mindfulness based stress reduction.

Dependent variables: Anxiety, Depression, Suicidal ideation.

Method: 79 Veterans at an urban Veterans health administration medical facility participated in the MBSR course for nine weekly sessions that included seated and walking meditations, gentle yoga, body scans and discussion of pain, stress and mindfulness. Participants were either referred by their clinicians or self selected to participate after learning about the course from a flyer that was posted at the clinics. Questionnaires were administered before and after participation in the course. The questionnaires investigated pain, anxiety, depression, suicidal ideation and physical and mental health functioning. The data from before and after the courses was compared to assess whether changes in mindfulness were related to changes in the other outcomes. The inclusion criteria was every veterans that was interested in participating in the MBSR course, the exclusion criteria was veterans with severe dementia because they would not benefit from the course as much. The scales used in this study were SF-12 to measure general physical and mental health functionality. The Facet Mindfulness Questionnaire (FFMQ) to assess mindfulness through 39 items. Pain was rated using 1 item from the PEG scale to assess average past week pain intensity. Depression and suicidal ideation were assessed with the 9-item Patient Health Questionnaires-9 (PHQ-9) (6).

Results: All but two participants of 79 completed the MBSR course which we defined as attending a minimum of 6 of the 9 sessions. Significant improvements were noted in mindfulness, anxiety, depression and general mental health functionality from baseline to the conclusion of the 9-week class. The unique aspect of this study was that it included veterans with active psychosis, severe personality disorders and active substance use disorders. One quarter of the population expressed active suicidal ideation (6).

Discussion: The study had a few limitations. One of the limitations stememd from the fact that they study did not use patient medical records. Therefore the influence of medical conditions on variables that were not weighed in. The other limitation was that this was an observational study and not a randomized one so the results did not include placebo effects. There was a discrepancy in improvement in pain as an effect of mindfulness compared to other recent studies. One of the reasons of this finding could be due to the limited assessment of pain used or to patient related characteristics that may have made pain less responsive. For example pain chronicity, presence of multiple co-morbid pain disorders and opiate dependent chronic pain in the veteran population. A more thorough assessment of pain should be part of future studies (6).

Study 4: Comparing the effects of Mindfulness Based Stress Reduction and Cognitive Behavioral Therapy: A pilot study

Purpose: The purpose of this study was to compare the effects of Mindfulness Based Stress Reduction (MBSR) and Cognitive Behavioral Therapy (CBT) on factors such as perceived stress, depression, psychological well-being, neuroticism, binge eating, energy, pain and mindfulness (7).

Independent variables and dependent variables: MBSR and CBSR and perceived stress, depression, psychological well-being, neuroticism, binge eating, energy, pain and mindfulness.

Independent variables: Mindfulness based stress reduction, cognitive behavioral therapy.

Dependent variables: perceived stress, depression, psychological well-being, neuroticism, binge eating, energy, pain and mindfulness.

Method: 64 subjects began the intervention and self selected either the MBSR and CBT course.  45 chose MBSR 19 chose CBT. 50 subjects remained in the program until conclusion. 36 Participants chose MBSR and 14 selected CBT. The courses were 8 weeks long each and had one weekly meeting for three hours and were offered to the community at a university. There was no initial or concluding differences in the participants in terms of  demographics, health, income, education or gender. Weekly meetings for both courses were held in a large room on a university medical center campus. Questionnaires for each measure were administered one week before and one week after the completion of the course. Binge eating scale assesses the severity of binge eating and the uncontrolled consumption of the large amount of food. It includes 16 items with 4-point scale. The Beck depression inventory II (BDI-II) was used to asses depressive symptoms over the previous two weeks. There are 21 items on the BDI-II. Energy levels were measured by using a visual analog scale. Mindfulness awareness and attention (MAAS) is a measure of receptive awareness of and attention the present moment to moment experiences. This scale has 15 items that range on a 6 point scale. Neuroticism was assessed by using the 8-item from a measure of the big give personality factors and was on a 5 point scale. Pain level was assessed using the analog scale. Perceived stress was assessed using the Perceived Stress Scale (PSS) and it consists of 10 items.  The Scales of Psychological Well-being (SPWB) was used to assess the psychological well-being of the participants. It consists of 18-items on a 6-point scale (7).

Results: The results indicate that both MBSR and CBSR are effective in reducing perceived stress and depression. MBSR is more effective in increasing mindfulness and energy, reducing pain, and possibly in reducing binge eating. The reduction in perceived stress and depression occurred in both interventions. MBSR group showed an increase in mindfulness. MBSR was associated with improvements on all eight measures with all differences being significant. CBSR was associated with improvements on 6 out of 8 measured with significant improvements in perceived stress, depression and well-being.

Conclusion: The increased effectiveness of MBSR with regard to these outcomes may be related to the fact that the mindfulness intervention promoted the idea of acceptance and having openness to the present moment without judgment. This study lacked a randomized control group which can increase the power of the study (7).

Study 5: Effects of Mindfulness-Based Cognitive Therapy on Body Awareness in Patients with Chronic Pain and Comorbid Depression

Purpose: To study the effects of mindfulness based cognitive therapy on raising body awareness and to treat chronic pain and comorbid depression (8).

Independent variables: Mindfulness based cognitive therapy.

Dependent variables: Body awareness.

Study Design: Randomized control study.

Method: 70 patients were screened for the study and a sample of 40 patients were selected from outpatient clinics after being informed about the course. 31 patients were randomized to join in the mindfulness course plus treatment as usual (TAU). 14 patients were randomized in TAU only. Body awareness was measured by a subset of the Multidimensional Assessment of Interoceptive Awareness (MAIA) scales which is  a32-item scale and deemed most relevant for the population. These included: Noticing, Not-Distracting, Attention Regulation, Emotional Awareness, and Self-Regulation. In addition, pain catastrophizing was measured by the Pain Catastrophizing Scale (PCS). Depression severity was measured by the Quick Inventory of Depressive Symptomatology—Clinician rated (QIDS-C16). Participants were randomly assigned to treatment as usual (TAU) or TAU plus mindfulness-based cognitive therapy (MBCT). The intervention consisted of an 8-week group skills program with one 2-h mindfulness training session each week and individual exercises for homework practice. It was modeled on the MBCT program developed by Segal et al. (2013), which was developed as a program to address recurrent depressive episodes and combines elements of cognitive behavioral therapy (CBT), such as psycho-education, with experiential mindfulness practices. Types of chronic pain included: chronic back pain, neuropathic pain, osteoarthritis, fibromyalgia, and migraines. The inclusion criteria was English-language literate individuals aged 18 or older that had persistent chronic pain for a minimum of 3 months, met the DSM-IV criteria for MDD, Dysthymic Disorder, or Depressive disorder Not Otherwise Specified (NOS). Exclusion criteria were: serious suicide or homicide risk; current or past bipolar disorder, current psychotic symptoms, or a current or past primary psychotic disorder; diagnosis of substance abuse or dependence disorder during the last 3 months; general condition that impedes attendance in group interventions, such as severe personality disorders, cognitive impairment, or tendencies toward physical aggression; severe and unstable medical illness including cardiovascular, hepatic, renal, respiratory, endocrine, neurological, or hematological disease; and significant present meditation practice with more than 3 h of mindfulness, insight, or vipassana meditation per week (8).

Results: MBCT resulted in increases for several dimensions of body awareness in the studied patient population. More specifically, a significantly greater increase in Self-Regulation and Not Distracting, but no changes in Noticing in the MBCT group as compared to the TAU group were observed. In addition, participants in the MBCT group, but not in the control group, had increases in Emotional Awareness. For Pain Catastrophizing, we found significant decreases within the treatment group, but not within the control group. Furthermore, mediation analyses revealed that the effect of MBCT on depression was mediated by Not Distracting, but not by Self-Regulation (8).

Conclusion: The control group of this study was TAU therefore, we missed observing any placebo effects. Patient medical records were not included as part of assessment to generate results for this study which may have influenced the outcome (8).

Conclusion

All of the five studies concluded that identifying a non-pharmacological intervention, specifically such as the practice of mindfulness exercises, can be an effective development towards the treatment of depression. Individuals who practice mindfulness practices on a regular basis tend to respond to situations rather than react to them.This practice can also be ideal for a patient population that may not seek treatment due to stigma. However, four of the five studies lacked a randomized control group and self-selecting bias due to measurements through different scales used without corresponding clinical data  threatens the internal validity.The study that did have a randomized control group consisted of mainly Caucasian females therefore lacked diversity and can not be generalized to other populations, a threat to external validity of the study. It remains difficult to mitigate effects of patients learning new skills during course of intervention. Future studies should include patient medical records and clinical evaluation for a more thorough assessment of the effects of mindfulness on depression.

References

(1) Burcusa S, Lacono W. Risk for Recurrence in Depression, Clin Psychol Rev. 2007 ; 27(8):959-985  doi:  10.1016/j.cpr.2007.02.005

(2) Lazar S, Kerr C, Wasserman R, Gray R, Greve D, Treadway M,  Fischl B. Meditation experience is associated with increased cortical thickness. Neuroreport, 16(17), 1893-1897.

(3)Vestergaard-Poulsen P, Van Beek M, Skewes J,  Bjarkam C. Stubberup M, Bertelsen J, Roepstorff, A. Long-term meditation is associated with increased gray matter density in the brain stem. Neuroreport, 2009; 20(2), 170-174.

(4) Falsafi, N. A Randomized Controlled Trial of Mindfulness Versus Yoga: Effects on Depression and/or Anxiety in College Students. J Am Psychiatr Nurses Assoc 2016; 22 (6)  DOI: 10.1177/1078390316663307

(5) Shaffer K, Riklin E, Jacobs J, Rosand J, Vranceanu A,  Mindfulness and Coping Are Inversely Related to Psychiatric Symptoms in patients and informal Caregivers in the Neuroscience ICU: Implications for Clinical Care. Society of Critial Care Med. 2016 ;44(11):2028-2036.

(6) Serpa T, Tillisch K. MBSR reduces Anxiety, Depression and Suicidal Ideation in Veterans, Med Care, 2014 ; 52 (12 Suppl 5): 19-24  DOI: 10.1097/MLR.0000000000000202

(7) Smith B, Shelley B, Dalen J, Wiggins K, Tooley E, Bernard J. Comparing the effects of Mindfulness Based Stress Reduction and Cognitive Behavioral Therapy, Journal of Altern Copliment Med 2008 ; 14(5): 251-256  DOI: 10.1089/act.2008.14505

(8) Jong M, Lazar S, Hug K, Mehling W, Holzel B, Sack A, Peeters F,  Mischoulon D, Gard T. Effects of Mindfulness-Based Cognitive Therapy on Body Awareness in Patients with Chronic Pain and Comorbid Depression. Front Psychol. 2016; 7: (967). doi:  10.3389/fpsyg.2016.00967

This paper has received no financial support.