Findings from the largest survey ever mounted on the prevalence of psychiatric disorders among US adults afford a sharper picture than previously available of major depressive disorder in specific population subgroups and of major depressive disorder’s relationship to alcohol use disorders and other mental health conditions. The new analysis of data from the 2001-2002 National Epidemiologic Survey of Alcoholism and Related Conditions (NESARC) has shown for the first time that middle age, Native American ethnicity, female gender, low income, and separation, divorce, or widowhood increase the likelihood of current or lifetime major depressive disorder. Asian, Hispanic, and black race/ethnicity reduce that risk. Conducted by the NIH’s National Institute on Alcohol Abuse and Alcoholism (NIAAA), the study appeared in the October Archives of General Psychiatry.

THE NESARC

The NESARC involved face-to-face interviews with 43,093 noninstitutionalized individuals 18 and older and questions that reflect diagnostic criteria established by the DSM-IV. Its principal foci were alcohol dependence (alcoholism) and alcohol abuse and the psychiatric conditions that most frequently co-occur with those alcohol use disorders. “Because of its size and scrutiny of multiple sociodemographic factors, the NESARC provides more precise information than previously available on between-group differences that influence risk,” remarked principal investigator Bridget F. Grant, PhD. Dr. Grant is Chief of the Laboratory of Epidemiology and Biometry, NIAAA, Bethesda, Maryland.

DEPRESSION BOOM

The analysis indicated that 5.28% of US adults had experienced major depressive disorder during the 12 months preceding the survey, and 13.23% had experienced major depressive disorder at some time during their lives. The highest lifetime risk was among middle-aged adults (ages 45 to 64), a shift from the younger adult population shown to be at highest risk in surveys conducted during the 1980s and 1990s. “This marks an important transformation in the distribution of major depressive disorder in the general population and specific risk for baby-boomers,” noted the authors.

Risk for the onset of major depressive disorder increased sharply between ages 12 and 16 and more gradually until the early 40s, when it begins to decline, with mean age at onset of about 30, the investigators reported. Women were twice as likely as men to experience major depressive disorder and somewhat more likely to receive treatment. About 60% of persons with major depressive disorder received treatment specifically for the disorder, with a mean treatment age of 33.5—representing a lag time of about three years between onset and treatment. Of all persons who experienced major depressive disorder, 45.5% wanted to die, 36.4% had considered suicide, and 8.8% reported a suicide attempt, Dr. Grant and colleagues found.

ETHNIC DIVIDE

Among racial/ethnic groups, Native Americans showed the highest (19.17%) lifetime major depressive disorder prevalence, followed by whites (14.58%), Hispanics (9.64%), blacks (8.93%), and Asian or Pacific Islanders (8.77%), the investigators reported. Since information is scarce on diagnosed mental disorders among Native Americans, this finding appears to warrant increased attention to the mental health needs of that group, the researchers maintained.

DEPRESSION AND SUBSTANCE DISORDERS

Among persons with current major depressive disorder, 14.1% had a concurrent alcohol use disorder; 4.6%, a drug use disorder; and 26%, nicotine dependence, Dr. Grant and colleagues reported. Among persons with lifetime major depressive disorder, 40.3% had experienced a comorbid alcohol use disorder, 17.2% had experienced a comorbid drug use disorder, and 30% had experienced comorbid nicotine dependence.

“The NESARC results demonstrate a strong relationship of major depressive disorder to substance dependence and a weak relationship to substance abuse, a finding that suggests focusing on dependence when studying the relationship of depression to substance use disorders,” the investigators observed. “This research direction is supported by earlier genetic studies that identified factors common to major depressive disorder and alcohol dependence and at least one epidemiologic study that demonstrated excess major depressive disorder among long-abstinent former alcoholics.”

Coexisting substance dependence disorder and major depressive disorder predict poor outcome among clinic patients, the authors noted. “A decade ago, many treatment leaders discouraged treating major depressive disorder in patients with substance dependence, on the grounds that arresting substance dependence was the more immediate need and that its resolution well might also resolve major depressive disorder. Results from foregoing epidemiologic surveys and several clinical trials over time altered that picture so that treating both disorders simultaneously is today common practice,” they said.

“Major depression is a prevalent psychiatric disorder and a pressing public health problem. That it so often accompanies alcohol dependence raises questions about when and how to treat each diagnosis,” commented NIAAA Director Ting-Kai Li, MD. The NESARC results “both inform clinical practice and provide researchers with information to advance hypotheses about common biobehavioral factors that may underlie both conditions.”

DEPRESSION AND PSYCHIATRIC COMORBIDITY

The NESARC also found strong relationships between major depressive disorder and anxiety disorders, with the strongest comorbidity for current diagnoses. “More than 37% of patients with major depressive disorder have a personality disorder and more than 36% have at least one anxiety disorder,” Dr. Grant reported. “But the magnitude of the association varied considerably among discrete personality disorder types,” she noted. For example, avoidant personality disorder had a 12-month adjusted odds ratio (OR) of 4.2, while antisocial personality disorder had an adjusted OR of 2.5 for that same period.

EPIDEMIOLOGIC SIGNPOST

“Our findings provide new insight into the prevalence of major depressive disorder, how this compares with earlier surveys, and its current demographic and psychiatric correlates,” Dr. Grant and colleagues said. “The variation in comorbidity by specific disorder highlights the importance of not collapsing disorders into broad categories and the need to better understand the variation. Given the seriousness of major depressive disorder, the importance of information on its prevalence, demographic correlates, and psychiatric comorbidity cannot be overstated. This study provides the grounds for further investigation in a number of areas,” they concluded.

Suggested Reading
Grant BF, Harford TC. Comorbidity between DSM-IV alcohol use disorders and major depression: results of a national survey. Drug Alcohol Depend. 1995;39:197-206.
Hasin DS, Goodwin RD, Stinson FS, Grant BF. Epidemiology of major depressive disorder. Arch Gen Psychiatry. 2005;62:1097-1106.
Hasin DS, Grant BF. Major depression in 6,050 former drinkers: association with past alcohol dependence. Arch Gen Psychiatry. 2002;59:794-800.
Helzer JE, Pryzbeck TR. The co-occurrence of alcoholism with other psychiatric disorders in the general population and its impact on treatment. J Stud Alcohol. 1988;49:219-224.

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