The Epidemiology of Depression

Lifetime Prevalence of Major Depressive Disorder by Age

Total (%)

18-29 (%)

30-44 (%)

45-59 (%)

60+

Major depressive disorder 16.6 15.4 19.8 18.8 10.6

Source: Kessler RC et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry 62:593-602.

Compared to adults over the age of 60 years, 18-29 year olds are 70% more likely to have

experienced depression over their lifetime 30-44 year olds are 120% more likely 45-49 year olds are 100% more likely

While major depression is less common among the elderly, 12-20% suffer from some depressive symptoms

Twelve-Month Prevalence of Major Depressive Disorder by Severity

Total (%)

Serious (% of all cases)

Moderate (% of all cases)

Mild (% of all

cases)

Major depressive disorder 6.7 30.4 50.1 19.5

Source: Kessler RC et al. Lifetime prevalence and age-of-onset distributions of DSM-IV disorders in the National Comorbidity Survey Replication. Arch Gen Psychiatry 62:593-602.

Incidence and Age of Onset (AOO)

First onset incidence: 1.6 per 100Average age of onset: 32 years old

Source: National Institute of Mental Health.

Subtypes of Major Depression

Subtypes Major depression with psychotic features (~14% of

depression) More severe course than nonpsychotic depression Increased risk of relapse, persistence over one year,

suicide attempts, hospitalization, comorbidity, financial dependency

Major depression with atypical features E.g., overeating and oversleeping Younger age of onset, more psychomotor slowing, more

comorbid panic disorder, drug abuse/dependence, and somatization disorder relative to depression without atypical features

Source: Horwath, Cohen, Weissman. Epidemiology of Depressive and Anxiety Disorders. In: Textbook in Psychiatric Epidemiology, MT Tsuang and M Tohen, eds. (2nd edition). Wiley-Liss, 2002: New York.

The Global Burden of Disease

The Global Burden of Disease Study conducted by the World Health Organization found that depression was one of the most disabling diseases in the world Due to the number of Disability-Adjusted Life Years (DALYs) and Years of

Life Lost (YLL) associated with the disease, depression ranked as the fourth most disabling disease in the world

Source: Horwath, Cohen, Weissman. Epidemiology of Depressive and Anxiety Disorders. In: Textbook in Psychiatric Epidemiology, MT Tsuang and M Tohen, eds. (2nd edition). Wiley-Liss, 2002: New York.

Sociodemographic Factors Associated with Depression

Women are 70% more likely than men to experience depression during their lifetime

Non-Hispanic blacks are 40% less likely than non-Hispanic whites to experience depression during their lifetime

Age is associated with depression, with the strongest association among 30-44 year olds

Lower level of education and employment classification Homemakers

Separated, divorced, or widowed

Sources: National Institute of Mental Health

Family History

Depression tends to cluster in familiesFirst-degree relatives of individuals with

major depression have a 2-3 fold increased risk of disease

Concordance of depression is higher in monozygotic twin pairs (27%) relative to dizygotic twin pairs (12%), suggesting a genetic contribution

Source: Horwath, Cohen, Weissman. Epidemiology of Depressive and Anxiety Disorders. In: Textbook in Psychiatric Epidemiology, MT Tsuang and M Tohen, eds. (2nd edition). Wiley-Liss, 2002: New York.

Comorbid Conditions

Dysthymic disorder is associated with a five-fold increase of depression

Schizophrenia is associated with ~3-fold increase in first-onset major depression

50-60% of individuals with a lifetime history of major depression have a history of one or more anxiety disorders

Source: Horwath, Cohen, Weissman. Epidemiology of Depressive and Anxiety Disorders. In: Textbook in Psychiatric Epidemiology, MT Tsuang and M Tohen, eds. (2nd edition). Wiley-Liss, 2002: New York.

Suicide

In 2007, suicide was the tenth leading cause of death in the United States Third leading cause of death for young people ages

15-24 years

There are an estimated 11 attempted suicides per every suicide death

Source: National Institute of Mental Health

Risk Factors for SuicideDepression and other mental disorders, substance-

abuse disorderPrior suicide attemptFamily history of mental disorder or substance

abuse, suicideFamily violenceFirearms in the home (used in more than half of

suicides)IncarcerationExposure to the suicidal behavior of others

(family, peers, or media figures)

Source: National Institute of Mental Health

Sociodemographic Factors Associated with Suicide

Highest rates among American Indian and Alaska Natives (14.3 per 100,000) and Non-Hispanic Whites (13.5 per 100,000)

Lower rates among Asian and Pacific Islanders (6.2 per 100,000); Hispanics (6.0 per 100,000); non-Hispanic Blacks (5.1 per 100,000)

Source: National Institute of Mental Health

Risk Factors for Suicide

~4 times as many men as women die by suicide

Firearms, suffocation, and poison are the most common methods of suicide Firearms are used in 56% of male suicides, 30% of

female suicides Poisoning is used in 40% of female suicides, 13% of

male suicides

Source: National Institute of Mental Health

Suicide Rates in the United States