People who have a depressive or anxiety disorder are at least twice as likely to wake up with a headache in the morning as those without the disorders, according to a study of more than 18,000 subjects in Europe.

In fact, according to the study’s principal investigator, Maurice Ohayon, M.D., Ph.D., the headaches may be a "signal symptom" of major depression.

Ohayon sought to determine the prevalence of "chronic morning headaches," or headaches experienced upon awakening, in the general population. He then explored whether the headaches were associated with a number of variables, such as sociodemographic characteristics, sleep disorders, and psychiatric disorders.

Ohayon is director of sleep epidemiology at Stanford University.

In order to gather the data, interviewers called a random sample of 18,980 people over age 15 living in the United Kingdom, Germany, Italy, Portugal, or Spain from 1994 to 1999.

When questioning subjects about sociodemographic characteristics, sleep habits, and mental health, interviewers used Sleep-EVAL software, which Ohayon developed. The software includes diagnostic information derived from the DSM-IV and the International Classification of Sleep Disorders.

Ohayon determined that 7.6 percent of the sample, or 1,442 people, experienced morning headaches.

People with comorbid depressive and anxiety disorders had the highest chance of experiencing morning headaches; they were 3.5 percent more likely to experience the headaches as those without the comorbid psychiatric disorders.

Subjects with major depressive disorder alone were 2.7 times as likely to experience morning headaches as those without depression, and those with anxiety disorder alone were almost twice as likely to suffer from the headaches.

According to Ohayon, the headaches can be a somatic manifestation of depression. He also noted that the relationship goes both ways—if severe enough, the headaches can also cause a person to feel depressed.

He found that other variables associated with chronic morning headaches included insomnia, sleep-related breathing disorders, and a high level of stress.

Further research should focus on the nature of the relationship between chronic morning headaches and psychiatric disorders such as major depression, he told Psychiatric News.

An abstract of the article, "Prevalence and Risk Factors of Morning Headaches in the General Population," is posted online at http://archinte.ama-assn.org/cgi/content/abstract/164/1/97?. ▪

Arch Intern Med  200416497