Investigating Exercise for Anxiety and Depression Treatment: A Case Report

Epidemiology

Mental illnesses, such as depressive and anxiety disorders, are functional impairments due to perturbations of one or more of the following: biological function, psychodynamic adaptation, learned behavior, genetics, and social/environmental conditions (1). Depression is a mood disorder characterized by persistent sadness or depressed mood and loss of interest or pleasure in normal daily activities.

Types of depression include major depression, dysthymia, and bipolar disorder. Common anxiety disorders include generalized anxiety disorder, panic disorder, phobias, and obsessive-compulsive disorder. Symptoms consistent with irrational fear and arousal of the autonomic nervous system are common in anxiety disorders.

Major depressive disorder (MDD) is a highly prevalent condition, affecting over 17 million people annually in the United States, with less than 50% of those affected receiving treatment. The prevalence of MDD is estimated about 1 in 5 in high-income countries and 1 in 27 in low-income settings (1). Anxiety disorders are also highly prevalent, affecting approximately 19 million Americans, making it the most common type of mental illness. The estimated cost of anxiety disorders is approximately $50 billion annually. Clinically, anxiety and depressive disorders are typically classified as “mild, moderate, or severe” depending on the level of psychosocial impairment.

Both men and women experience anxiety disorders; however, women have a higher incidence. Women are also twice as likely as men to experience clinically significant depression. Anxiety and depression disorders are not mutually exclusive, since some patients with clinically significant depression also experience anxiety.

Additionally, depression among individuals with coronary heart disease is approximately 40%, with the risk of major depression 5-fold greater than in the general population (2). Further, individuals who are diagnosed with either depression or anxiety are at greater risk of all-cause mortality (3).

Etiology

Historically, the causes of anxiety and depression were thought to lie in the psychology of the patient, with treatment focused on understanding and treating the root cause. More recently, however, scientists have gained a greater understanding of the biological basis for these disorders and pursued new avenues of treatment with increasing success.

Depression is known to occur more often in some families and may therefore have a genetic basis. Mental illness is associated with poor cardiometabolic outcomes, with approximately 30% of people with MDD also having metabolic syndrome, which is significantly greater than people without MDD (4,5). Physical illnesses—such as heart disease, cancer, and obstructive lung disease—are also associated with an increased risk for depression.

Men, partly due to stigma and the conversation around mental illness, may be less likely to seek help or report experiencing depression. Women, on the other hand, are twice as likely as men to experience or report experiencing depression.

Anxiety disorders are characterized by unpleasant feelings of apprehension and thoughts of worry. They stem from irrational fears, possibly the result of prior conditioning that established specific neural pathways in the brain. Once established, these pathways are difficult to overcome, and their presence makes normal daily functioning difficult for many and impossible for some. Physiological pathologies such as hyperthyroidism or the use of legal/illegal substances (e.g., cocaine, steroids) may elicit or mimic anxiety. The physiological basis of primary anxiety disorders remains elusive.

In addition, chronic illness commonly presents as a risk factor for major depression. Both depression and anxiety are commonly associated with poor physical health including an increased risk of cardiometabolic diseases such as type 2 diabetes, obesity, and cardiovascular disease (6). These diseases contribute to the significant reduction in life expectancy seen in people living with mental illness (7).

Clinical Manifestations

Onset and severity of symptoms vary across individuals and across time. The more common symptoms of clinical depression are presented in the next section. Not all individuals will experience all symptoms, but clusters of symptoms are frequently evident. The symptoms of anxiety disorders are centered on a patient's fear. Symptoms often depend on the type of anxiety disorders. Table 1 provides a synopsis of symptoms relevant to anxiety disorders.

TABLE 1. Common symptoms of anxiety disorders.

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Diagnosis

A diagnosis of depression usually begins with a physical examination and laboratory tests to rule out medical conditions or medications that may produce similar symptoms. Assuming no illness is identified, a thorough history and interview of the patient is warranted. Quantifying the frequency, duration, and onset of symptoms is important, along with a history of substance abuse and whether there have been thoughts of suicide. Data concerning any family history of depressive disorders are also useful for making a proper diagnosis.

There are several self-report measures to assess the presence and severity of depressive symptoms. These measures include the Beck Depression Inventory – II (BDI-II)(8), Kessler 10 (K-10) (9), The Patient Health Questionnaire (PHQ-9) (10), Center for Epidemiological Studies Depression Scale (CES-D) (11), and the Hospital Anxiety and Depression Scale (HADS) (12). These measures are not diagnostic tools but may be used to guide decision-making for treatment approaches for allied health professionals.

Symptomatic criteria for the diagnosis of depression include the presence of a depressed mood or a loss of interest or pleasure in normal activities, plus four or more of the symptoms listed in the box below that persist for at least 2 weeks.

The diagnosis of anxiety disorders often follows a pattern similar to the one used to diagnose depression. Since each anxiety disorder has its own manifestations, readers are referred to the Diagnostic and Statistical Manual of Mental Disorders – 5 (DSM-5) for a comprehensive review (13). Suffice it to say that anxiety symptoms, avoidance behaviors, and increased arousal are common to many of the anxiety disorders.

Treatment

The treatment for depression may include antidepressant medications and/or psychotherapy. Types of medications used to treat depression include monoamine oxidase inhibitors (MAOIs), tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), and atypical antidepressants.

While MAOIs and TCAs have been used for a longer period of time, the newer SSRIs and SNRIs have fewer side effects and are better tolerated by many patients. Psychotherapy, particularly cognitive-behavioral therapy (CBT) and interpersonal therapy (IPT), have been successful in treating depression.

Coronary artery disease complicates the treatment process of depression. The use of tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs) have been discouraged for patients with cardiac disease due to adverse events (e.g., QT interval prolongation, hyper/hypotension, arrhythmias) (14). Sertraline, an SSRI, is established as a safe medication to treat depression for cardiac patients (15). However, its effectiveness in significantly reducing depressive symptoms is not definite as many patients may not respond to, or tolerate, antidepressants, leading to dropouts and reductions in adherence to medication.

Anxiety disorders are also treated with psychotherapy and/or pharmacotherapy. Among patients being treated for anxiety, cognitive-behavioral therapies are the most common forms of psychotherapy. Medications used to treat anxiety disorders include benzodiazepines, antidepressants, and buspirone.

Exercise Testing

Guidelines outlining indications for a graded exercise test should be applied to individuals diagnosed with anxiety or depression who intend to start an exercise program (16). Exercise testing, whether maximal or submaximal, may be useful in developing an exercise prescription, quantifying functional capacity, identifying appropriate exercise-related goals, and providing an outcome measure. Exercise testing may include an aerobic test to determine cardiovascular fitness, strength and balance testing, and functional and flexibility assessments.

Exercise Training

There is an increasing body of evidence supporting the role of exercise for improving mental health outcomes for those living with mental illness (17). Exercise has been shown to be an effective component of treatment. Blumenthal et al. (18) was the first to compare pharmacotherapy and exercise by randomizing 156 individuals (age = 57 ± 7 y; 28% men) with major depressive disorder to a) aerobic exercise training (30 min, 3 d·wk⁻¹), b) antidepressants (sertraline), or c) combination exercise training and antidepressant (19). Dropout rate was 20% and was similar for all groups. While reductions in depression scores were more rapid among those taking antidepressants, both the combination group and the exercise-alone group showed similar significant reductions in depression scores. Additionally, both intervention groups showed improvements in peak VO₂ (9%–11%) compared to the control group.

Babyak et al. (19) followed up with patients in the above trial by Blumenthal et al. at 6 months after the initial study period. Based on depression scores, patients in the exercise-only group were six times more likely to be partially or fully recovered at 6 months. Additionally, fewer patients in the exercise-only group relapsed after the intervention. Among patients randomized to the other therapy options, exercise was recommended at the end of the clinical trial. Exercise compliance was 64%–66% for both groups using exercise training. Among patients in the medication group, 44% began a home exercise program. At 6 months, home exercise was associated with fewer depression diagnoses.

To compare the effects of exercise training versus a standard drug treatment strategy in patients with panic disorder, Broocks et al. (20) randomized 46 patients to 10 weeks of aerobic exercise training and clomipramine or a placebo. Group dropout rates were 31% for exercise, 27% for placebo, and 0% for clomipramine. In comparison to placebo, both the exercise and clomipramine groups showed significant reductions in symptoms. However, these reductions occurred earlier and were more effective in the clomipramine group.

Trivedi et al. (21) later found that exercise can also be an effective augmentation to treatment for people with treatment-resistant depression. This study reported that for patients performing 12 weeks of structured exercise training at either a high (16 kcal per kg per week expended) or low (4 kcal per kg per week expended) program, there was an increased rate of depression remission, with a trend toward better outcomes in the high-dose group.

Finally, a recent meta-analysis (22) examined 6 randomized controlled trials (20,23–27) on exercise interventions for anxiety and stress related disorders. Of those studies, exercise had a moderate effect on the reduction of anxiety symptoms that was similar in magnitude to medication treatments such as paroxetine, fluoxetine, quetiapine, fluvoxamine, and venlafaxine (28).

Exercise Prescription

There is no one-size-fits-all prescription for people diagnosed with anxiety or depressive disorder. However, most studies suggest that a general aerobic and resistance training program 3 to 5 times per week for 45 to 60 min can improve symptoms of both depression and anxiety (29). That said, it remains unclear whether a threshold of exercise to elicit an antidepressant response exists or whether one type of exercise is superior to another. Foremost, the exercise should be designed to encourage regular participation and foster long-term compliance. It is important to find the type of exercise people enjoy so they are more likely to maintain it. Cardiorespiratory, strength, and flexibility exercises (such as yoga) can all be of benefit for this population.

The overall consensus for effective exercise for the treatment of depression is not substantially different to that of the general population (30). While the current guidelines for the general population recommend 150 min of moderate physical activity per week or 75 min of vigorous activity—any increase in physical activity levels is valuable. In fact, as little as 1 h of exercise per week may help prevent depression (31). It is also important to remember that those with a mental illness usually have low cardiorespiratory fitness, so it would be more feasible starting with low-intensity exercise (such as walking) a few days a week and increasing gradually.

Low mood and stress have been identified as the most prevalent barriers to physical activity in people with severe mental illness, followed by a lack of support (32). It has been suggested that increasing autonomous motivation may be the most important component involved in increasing and maintaining physical activity levels in this population (33). It is recommended that exercise be prescribed with some level of supervision from an exercise professional, at least initially, who can help provide education and set realistic goals.

Since social support is a strong predictor of exercise adoption and maintenance, encouraging people with mental illness to exercise with friends or family or in a group situation may increase reductions in symptoms and increase the chances of maintenance. Finally, encouragement and acknowledgement of progress no matter how small should be promoted.