Epidemiological Studies Depression

Radloff, L.S. The Centre for Epidemiologic Studies - Depression Scale (CES-D) a self report depression scale for research in the general population. Appl. Psychol. Mens. 1, 385-401, 1977. 

Chan, K.S., Orlando, M., Ghosh-Dastidar, B., Duan, N. and Sheiboume, C.D. 2004. The interview mode effect on the Center for Epidemiology Studies Depression (CES-D) scale An item response theory analysis. Medical Care, 42, 281-9. 

Those individuals who had whiplash pain but who did not report being depressed prior to the whiplash event were followed for future symptoms of depression, using the Epidemiological Studies Depression Scale [8j. In this follow-up, 42% of whiplash subjects who had not been previously depressed met the definition for depression over the next 6 weeks. The majority (60%) of these 42% experienced resolution within the subsequent year, with a median recovery time of 92 days, whereas 19% experienced recurrent bouts of 343... 

Anxiety disorders and insomnia represent relatively common medical problems within the general population. These problems typically recur over a person s lifetime (3,4). Epidemiological studies in the United States indicate that the lifetime prevalence for significant anxiety disorders is about 15%. Anxiety disorders are serious medical problems affecting not only quaUty of life, but additionally may indirecdy result in considerable morbidity owing to association with depression, cardiovascular disease, suicidal behavior, and substance-related disorders. 

Bipolar disorders have been categorized into bipolar I disorder, bipolar II disorder, and bipolar disorder, not otherwise specified (NOS). Bipolar I disorder is characterized by one or more manic or mixed mood episodes. Bipolar II disorder is characterized by one or more major depressive episodes and at least one hypomanic episode. Hypomania is an abnormally and persistently elevated, expansive, or irritable mood, but not of sufficient severity to cause significant impairment in social or occupational function and does not require hospitalization. Most epidemiologic studies have looked at bipolar disorder of all types (bipolar I and bipolar II), or the bipolar spectrum, which includes all clinical conditions thought to be closely related to bipolar disorder. The lifetime prevalence of bipolar I disorder is estimated to be between 0.3% and 2.4%. The lifetime prevalence of bipolar II disorder ranges from 0.2% to 5%. When including the bipolar spectrum, the lifetime prevalence is between 3% and 6.5%.1... 

Epidemiological studies have been carried out to investigate if there is a relationship between the amount of fish consumed and the incidence of depression. This was done for nine different countries. An inverse relationship was observed between the amount of fish consumed and the incidence of depression. 

An epidemiological study tested the effects of chronic exposure to jet fuel in factory workers (Knave et al. 1978). This study found significant increases in neurasthenia (i.e., fatigue, depressed mood, lack of initiative, dizziness, and sleep disturbances) in the exposed subjects when compared to unexposed controls from the same factory. Also, attention and sensorimotor speed were impaired in the exposed workers, but... 

In one case study, anorexia was reported in a man who washed his hands with diesel fuel over several weeks (Crisp et al. 1979). Effects resulting from inhalation versus dermal exposure could not be distinguished in this case. An epidemiological study found a significant increase in neurasthenia (i.e., fatigue, depressed mood, lack of initiative, dizziness, and sleep disturbances) in workers who were chronically exposed to jet fuels by either inhalation, oral, and/or dermal exposure (Knave et al. 1978). Also, attention and sensorimotor speed were impaired in the exposed workers, but no effects were found on memory function or manual dexterity. Results of EEG tests suggest that the exposed workers may have instability in the thalamocortical system. The limitations of the study were discussed in detail in Section 2.2.1.2 under Respiratory Effects. 

A number of epidemiological studies [including several reviewed in May and Lichterman 1993] have shown that panic disorder and unipolar depression occur more commonly together than could be explained by chance. Some 50%-70% of patients with panic disorder also have major depression [J. Johnson et al. 1990 Volrath and Angst 1989]. The association also holds true for seasonal depression [Halle and Dilsaver 1993] and to some extent for bipolar disorders [Savino et al. 1993]. 

In 1997, a large epidemiological study found that 11.3% of individuals with lifetime major depression had only episodes meeting atypical criteria ( 11). These patients (especially male patients) may also be at greater risk for sedative-hypnotic abuse. If the clinician is cognizant of these probabilities, preventive steps can be taken (e g., education about sedative-hypnotics). The identification of the nonclassic forms, as well as their differences in clinical presentation, has substantial implications for their differential treatment (see Chapter 7). 

To underscore the importance of adequate treatment for bipolar disorder, we note that it is estimated that one of every four or five untreated or inadequately treated patients commits suicide during the course of the illness, particularly during depressed or mixed episodes. Further, an increase in deaths secondary to accidents or intercurrent illnesses contributes to the greater mortality rate seen in this disorder in comparison with the general population. Unfortunately, recent epidemiological studies have indicated that only one third of bipolar patients are in active treatment despite the availability of effective therapies. 

We are not certain which comorbid risk factors cause mortality independent of sleep effects, and therefore, we cannot be certain whether we controlled too much or too little for comorbidities. For example, since short sleep or long sleep may cause a person to be sick at present or to get little exercise or to have heart disease (17), diabetes (18), etc., controlling for these possible mediating variables may have incorrectly minimized the hazards associated with sleep durations. This would be overcontrol. The hazard ratios for participants who were rather healthy at the time of the initial questionnaires were unlikely to be overcontrolled for initial illness. Since the 32-covariate models and the hazard ratios for initially healthy participants were similar, this similarity reduced concern that the 32-covariate models were overcontrolled. On the other hand, there may have been residual confounding processes that caused both short or long sleep and early death that we could not adequately control in the CPSII data set, either because available control variables did not adequately measure the confound or because the disease did not yet manifest itself. Depression, sleep apnea, and dysregulation of cytokines are plausible confounders that were not adequately controlled. It may be impossible to be confident that all conceivable confounds are adequately controlled in epidemiological studies of sleep. 

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