The incidence of different psychiatric diagnoses in Danish Psychiatric Hospitals are characterized by fluctuations. This phonemena could be due to changes in true incidence, changes in the entry into the health care system, changes in the diagnostic practices and the possibilities of treatment for a given disease, or due to changes in the attention towards the disease within the population, the profesionals or the medias.

Nowadays there is a notable increase of the number of new ADHD diagnoses among children and adults.

There is a need for epidemiological measures in ADHD in The Danish Psychiatric Health Care System.

To investige treated incidence in ADHD in adults in Denmark through the period of 1995–2012, and to investigate psychiatric comorbidity, latency from the first contact to the ADHD diagnosis and mortality.

From The Danish Psychiatric Central Research Register all patients with following diagnoses given for the first time ever after their 18th birthday were identified: ICD-10: F.90.0, F90.1, F90.8, F90.9, F98.8.

These data are used to make an age standardized incidence rate throughout the period differentiated with gender and possible existence of previous childhood psychiatric diagnosis. We will also analyze for psychiatric comorbidity after their primary ADHD diagnosis.

The statistical analysis are still in progress.

There is a marked increase in treated incidence in adult ADHD from the introduction of ICD-10 to 2012. Further results about psychiatric comorbidity and mortality will be presented.