[Mental disease as disturbance of essential functions].

Background: The article defends an interpretation of mental illness as mental dysfunction. It develops a concept in line with the naturalistic viewpoint in the philosophy of medicine.

Methods: The concept of mental function is scrutinized. Functions are regarded as effects of traits that enable an organism to live independently. The significance of this theoretical perspective for the psychiatric practice is discussed. Finally, the developed conceptualization is compared to the current edition of the diagnostic and statistical manual of mental disorders (DSM).

Results and Discussion: It is emphasized that the theoretical conceptualization of mental disorder determines what may justifiably and in a scientifically valid way be deemed a disease entity. Nevertheless, the practical perspective needs an additional element of individual well-being as not every mental dysfunction involves impairment in this respect. It is claimed that the DSM takes a perspective similar to the one defended in this article.