Depression epidemiology

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. 

Chen CY, Wagner FA, Anthony JC Marijuana use and the risk of major depressive episode epidemiological evidence from the United States National Comorbidity Survey. Soc Psychiatry Psychiatr Epidemiol 37 199-206, 2002... 

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... 

Hotopf, M., G. Lewis and C. Normand, Putting Trials on Trial - the Costs and Consequences of Small Trials in Depression A Systematic Review of Methodology Journal of Epidemiology and Community Health 51 (1997) 354-58... 

Depression for Older Adults , American Journal of Epidemiology 156, no. 4 (2002) 328-34... 

Weissman MM, Bland RC, Canino GJ, Faravelli C, Greenwald S, Hwu HG et al. Cross-national epidemiology of major depression and bipolar disorder. JAMA 1996 276 293-299. 

Believed historically to be a relatively rare disorder, large-scale epidemiological research undertaken during the last 20 years indicates that OCD is in fact quite common. The lifetime prevalence of OCD is 2-3%, making it more common, in fact, than bipolar disorder, schizophrenia, and most psychiatric illnesses other than depression and the substance use disorders. 

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. 

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