The European Study of the Epidemiology of Mental Disorders (ESEMeD) is the first large-scale survey to collect data comprehensively on the prevalence, risk factors, disability, and use of health care services associated with mood, anxiety, and alcohol-related disorders throughout Europe. Findings from the ESEMeD study are updated using a modified version of the Composite International Diagnostic Interview 3.0 in order to achieve the maximum diagnostic accuracy. The study is based on a sample of 21,425 noninstitutionalized adults, representative of an overall population of more than 212 million from Belgium, France, Germany, Italy, the Netherlands, and Spain. In total, 25.9% of participants reported a lifetime presence of any mental disorder, and 11.5% had experienced a mental disorder during the past 12 months. Females, younger participants, the unmarried, and the unemployed were more at risk, and comorbidity was prevalent. Associated levels of disability and reductions in quality of life exceeded levels seen in patients with chronic physical conditions. Nevertheless, only 36.8% of participants with a mood disorder and 20.6% with an anxiety disorder sought help from health care services; of these, 20.7% received no treatment. ESEMeD data provide an epidemiologic basis for reform of mental health policy within Europe.