Stress is an important occupational health problem and a significant cause of economic loss. While stress remains a broad and somewhat elusive concept, research efforts have led to a clearer understanding of the problem, its causes, and its consequences. When stress is deleterious, it may result in physical and/or mental disorders. It also may have more subtle manifestations that can affect personal well-being and productivity at work.
The mental health effects of stress exist on a continuum ranging from mild subjective symptoms to overt psychiatric disease with significant impairment of functioning. Subjective reports regarding personal well-being constitute some of the earliest measures of stress. Frequently noted symptoms include anxiety, tension, anger, irritability, poor concentration, apathy, and depression. These manifestations of stress interfere with a sense of well-being and may be precursors of more severe illness.
Overt psychological dysfunction frequently is attributed to stress. The most frequent psychiatric diagnosis in the working population is that of an adjustment disorder or a time-limited emotional reaction to a specific psychosocial stressor. Stress may act as a nonspecific promoter of disease. Multiple studies show statistical associations between stressors and overt psychiatric disease. Unemployment and lack of opportunity for promotion both have been related to increased psychiatric hospitalizations and suicide rates.
There is a growing body of evidence to indicate that the prevention of occupational stress may be accomplished by creating a healthy work environment based on recognized organizational principles. Organizational solutions for high-stress work units offer promise, although there is not much experimental information available to guide these interventions. It also may be possible to monitor and control stress in the workforce by recognizing problem situations as well as early clinical or behavioral signs. When individual dysfunction arises, clinical intervention may be necessary.
There is a multifactorial relationship between occupational stress and injury in the workplace. Although there is little consistent evidence to demonstrate either the magnitude of stress-related injury or to confirm the mechanisms of the problem, this remains a promising area of stress research. A study of bus drivers demonstrated that psychological job demands, frequency of job problems, and job dissatisfaction all were related to back injuries. An increased risk of low-back pain is found in employees who report insufficient support from supervisors. In addition to high job demands, interpersonal conflict at work also may represent a separate risk factor for occupational injury. Job stress and nonwork-related stress reactions are consistently associated with upper extremity pain disorders.
The stress of high workload demands may lead to compromise of safety measures to attain higher productivity. Workers paid on a piecework basis have increased numbers of injuries. Attention span may be altered by low levels of stimulation and long periods without breaks; inattention can lead to accidents. Changes of shift are associated with higher rates of injury on the first days of new shifts. There is mounting evidence to relate shift changes and sleeplessness to airplane pilot and air traffic controller errors. There also may be a relationship between job decision latitude and frequency of injury. The contribution of stress to substance abuse also leads to accidents; a large proportion of motor vehicle accidents on the job involve alcohol.
Some authors note a relationship between stressful events in an employee's life and subsequent occupational accidents. The possibility exists that stress from work or personal factors may contribute to the likelihood of an accident. Stressors should be assessed when evaluating injured employees; treatment of the physical impairment alone may not result in a successful return to work.
Sickness, Absence, & Productivity
A clear relationship exists between sickness, absence from work, and lost productivity. Stress may be an independent variable influencing each of these three factors. The case for stress as a contributor to sickness already has been discussed. However, absence from work is a complex phenomenon involving not just organic disease but also mental health, motivation, satisfaction with employment, and other personal and work-related factors. Some research has demonstrated a relationship between organizational stressors, such as high-demand/low-control work, and subsequent absenteeism. However, research studies on stress and absenteeism are mixed. Some studies indicate that stressors appear to predict absences associated with a physician visit but not other absences.
Presenteeism, coming to work while ill, is more prevalent than absenteeism and is a significant contributor to loss of productivity. Presenteeism is associated with high stress, life dissatisfaction, depression, and mental illness. The costs associated with presenteeism can exceed the combined costs of absenteeism and medical treatment. Efforts to control psychosocial workplace factors that enhance presenteeism, including more effective management, may result in increased productivity and decreased health care costs.
Productivity on the job is a stress-sensitive function. Reduced output, production delays, and poor performance may be manifestations of stress. Declining productivity of an organization or individual should prompt a search for occupational stressors. A stress management program may promote increases in attendance and productivity.
ESSENTIALS OF DIAGNOSIS
Fatigue with work shift assignment.
Diminished work performance.
Aggravation of other diseases.
Changes in behavior.
Increased drug use.
Between 20% and 25% of the US workforce is assigned to some form of rotating shift work, evening, or night work. Rotating shifts usually involve regularly changing work hours. Employees' shifts change periodically (eg, every 2–30 days), so that times spent working day, evening, and night shifts are shared by the workforce. These schedule changes have consequences for mental and physical well-being, and may influence performance and safety.
Many physiologic systems operate within a regular circadian rhythm. The circadian pacemakers, which time the approximately 24-hour rhythms in sleep and wakefulness, resynchronize only slowly after an abrupt phase shift in environmental time cues. Examples of circadian physiologies include body temperature, glucocorticoid secretion, cognitive function, gastric emptying, pulmonary function, effects and metabolism of medications, and many psychological processes. While the symptoms of jet lag are transient, the repeated shifts in the activity/sleep schedule experienced by night-shift workers on rotating or permanent schedules are often associated with chronic sleep deprivation, and over a number of years, with increased risk for various medical disorders.
Bipolar disorder, persistent depressive disorder (dysthymia), or cyclothymic disorder
Major depressive disorder with seasonal pattern (seasonal affective disorder)
Substance use disorder
A key issue with shiftwork schedules is the readjustment, or entrainment, of these physiologic rhythms. With change from a day to a night work schedule, or as a result of travel over time zones, the normal synchronization of the various circadian physiologic rhythms is disrupted. Because each physiologic rhythm readjusts at its own rate, this internal desynchrony may last for long periods. There is seldom complete re-entrainment to night-shift work. Additionally, there is significant interindividual variation in the ability to adapt, and for some, deterioration of tolerance to shiftwork with ageing.
A significant portion of the shiftwork population has some level of desynchronosis at any given time. Poor adapters may develop a constellation of characteristic pathologic manifestations of shiftwork intolerance, sometimes referred to as shiftwork-maladaptation syndrome. Clinical intolerance to shiftwork has been defined by the presence of sleep alterations, persisting fatigue (not disappearing with normal time off periods), changes in behavior, digestive disturbances, and the regular use of sleeping pills.
In addition to disrupting biological rhythms, shiftwork, particularly that including night work, disrupts social and family life, potentially negatively affecting performance efficiency, health, and social relations. Proper alignment between sleep–wakefulness and internal circadian time is crucial for cognitive performance. Individuals with shiftwork sleep disorder are at risk for significant behavioral and health-related morbidity associated with their sleep–wake symptoms. Adverse effects can manifest themselves in the short term as sleep disturbances, psychosomatic troubles, mistakes at work, and accidents. Rotating shifts and night work aggravate many preexisting chronic disorders as a result of the disruption of circadian functions. In the long term, there is an increased risk for gastrointestinal, psychoneurotic, cardiovascular, and gastrointestinal diseases. Women shift workers are vulnerable to negative reproductive outcomes.
Medical surveillance programs have been recommended for shift workers and are mandatory in some countries. Rotating shifts and night work may aggravate some preexisting chronic disorders as a result of the disruption of circadian functions. Shiftwork may complicate management of chronic diseases for which timing and adjustment of medications are important. The implications for clinical case management are relevant and, in several instances, critical. Shiftwork can interfere with mechanisms regulating drug kinetics and actions at selective brain sites, either directly or through effects on the gastrointestinal/hormonal cycles. Insulin-dependent diabetes mellitus may be more difficult to control. There is evidence for a circadian variation in the effects of insulin, circadian rhythm in gastric emptying rate, and diurnal variation has been observed in the effect of the type of meal on blood glucose control. The alteration of the sleep cycle may increase seizure frequency in epileptics due to sleep deprivation or disturbance of medication regulation. Asthmatics may also experience difficulty with medication adjustments.
The risk of cardiovascular disease in shift workers is increased by about 40%. Some studies have indicated increases in hypertension in shift workers. Some studies show an increased mortality among shift workers. Obesity, high triglycerides, and low concentrations of HDL cholesterol seem to occur together more often in shift workers than in day workers, which might indicate an association between shiftwork and the metabolic syndrome. Shiftwork may be associated with insulin-resistance syndrome in workers younger than 50.
There is a potential reproductive risk from shiftwork. Reproductive outcomes among women shift workers include increased spontaneous abortions, preterm births, and intrauterine growth retardation. Studies of night shiftwork and breast cancer risk show an increased breast cancer risk among women. Night-shift work increases the risk of cancer at several sites among men and increases the risk for breast cancer among women.
Workers assigned to shiftwork schedules, and 12-hour working days, are significantly prone to neurotic disorders. There is a common disturbance of mood in dysrhythmic workers, with a disturbing tendency toward depression as the condition becomes chronic. The majority of individuals subject to shiftwork or jet travel–related time shifts in their sleep–wake schedules commonly report some degree of depressive symptoms.
Extensive disruption in circadian function is known to occur among patients with bipolar disorder. Therefore, it is plausible that circadian dysfunction underlies pathogenesis of this common abnormality. Subtle disturbances of short-cycle rhythms such as the REM/non-REM sleep cycle could contribute to the ultrarapid cycles of mood, energy, sleep, and activity that characterize early-onset bipolar disorder. Some studies demonstrate that licit and illicit drug use increases significantly in this group of workers, with no benefit to worker health or safety, and possibly adding to the chronicity of the problem.
There is substantial evidence that appropriately timed, bright-light treatments can successfully overcome the circadian misalignments associated with desynchronosis. The mood elevation and increased alertness that would result from this intervention might remove the influence that desynchronosis has in aggravating depression, drug abuse, and a variety of other mental health disturbances.
Stress & Workers' Compensation
In an attempt to restrict stress claims, some workers' compensation jurisdictions place restrictions on claims during the probationary period of employment, eliminate claims resulting from appropriate personnel actions, and increase the causation threshold to substantial or predominant cause. Some states require a co-occurring physical injury to validate a stress claim.
Stress-related workers' compensation claims may be divided into three categories: physical-mental, mental-physical, and mental-mental. Physical-mental claims usually result from well-defined work-related injuries such as crush injuries, amputations, or other sudden, significant, well-defined occurrences, although they also may result from illnesses. The claim is made for mental health effects such as posttraumatic stress, anxiety, or depression resulting from the physical event. Such claims are recognized in all US jurisdictions, although some claim types pose a challenge to the system. For example, mental health effects that an individual claims as a result of a gradually developing occupational disease, such as asbestosis, expand the scope of the physical-mental claim and raise new issues.
The mental-physical category includes instances in which claimants contend that emotional stresses at work have caused physical ailments, including a wide variety of disorders such as myocardial infarction and neurologic, dermatologic, and gastrointestinal diseases. The epidemiologic evidence linking emotional stress to the initiation or aggravation of these disorders is variable and often weak. In the United States, most states limit these claims by requiring the presence of an unusual stressor or a close coupling of the events in time.
In recent years, mental-mental claims have drawn the most attention, and the number of claims has grown rapidly. Claimants file for compensation on the basis of mental health effects resulting from conditions at work. There are fundamentally three kinds of situations that may precipitate these claims: stress resulting from involvement in sudden, emotionally disturbing events, such as witnessing a coworker's death; stress resulting from a continuing situation that is unusual in its demands on the worker (eg, air traffic controllers and some types of police work); and stress arising out of the conditions of everyday work. These claims, particularly the last group, often are difficult to resolve. Many of these cases involve interpersonal conflict, predominantly conflict with supervisors. Both the extent of impairment and the causal factors are difficult to assess objectively. Legal precedent has allowed the claimant's subjective perception of events to be a factor in determining compensability in many jurisdictions.
Alternative schema for categorizing psychiatric claims include those that involve a reaction to an admitted or acknowledged physical injury, an obviously psychologically traumatic event, and cumulative stress associated with the nature of the job position. Psychiatric claims are contentious because of the subjective nature of the evidence presented. In jurisdictions that allow for cumulative stress injuries, those claims tend to be heavily litigated. Prevention and early intervention of psychiatric injuries involve employee education, employee assistance programs, reasonable mental health benefits, and appropriate personnel policies.