The 21st century has witnessed unparalleled scientific advances in areas such as Genetics, cognitive neuroscience or biology. These advances have not been accompanied by an improvement in the treatment or diagnosis of mental disorders. Thus, for example, even leaving aside their limited efficacy, the most modern antidepressants were approved at the beginning of the current century. Why might this disconnect between scientific advances and treatments be due? Many believe it may be related to the very definition of mental illness.

The dominant paradigm in psychiatry has been that of assigning "labels" (disorders) that have been agreed among experts, are based on the joint presentation of symptoms, and are embodied in diagnostic manuals, the best known of which is the DSM (currently in its fifth version) of the American Academy of Psychiatry. These manuals, by offering a common language to professionals, have allowed clinical judgments to be reasonably independent of the physician making them.

However, this approach has also received numerous criticisms related to the validity of its diagnostic labels. For example, it does not take into account the fact that the boundaries between disorders are often blurred. The occurrence of delusions or even hallucinations in severe cases of depression is well known, while lack of motivation, typical of depression, is also a characteristic symptom of schizophrenia. In other medical specialties these limitations have been overcome, and diagnosis based on clinical symptoms alone has been displaced as the ultimate causes of the diseases were discovered. Certainly, symptoms alone can only occasionally lead to the choice of the most effective treatment.

In 2013 the U.S. National Mental Health high school suggested that the time had come to investigate alternatives that could replace the current mental disorder classifications. To this end, it proposed a new framework from research with the name "Research domain Criteria" (RDoC) and its almost unintelligible translation "Domain Criteria from the research". The framework RDoC assumes that mental illnesses are dysfunctions in brain systems relevant to biological adaptation, such as neural circuits responsible for processing rewards or threats. It also assumes that such dysfunctions manifest themselves in markers that are objectively assessable. Examples of these possible markers include genetic analyses, biological samples (markers in blood, cerebrospinal fluid, etc.), or neuroimaging tests. It is thought that the results of these markers have the potential to allow patients to be grouped into new and more accurate categories, and that, being so, should translate into more effective treatments, insofar as they would be directed at modifying biologically relevant mechanisms.

Our programs of study with the University of Cambridge indicates that there are indeed biological dimensions that go beyond current diagnostic labels, and that could be useful to distinguish between groups of patients. In particular, we have shown that it is more frequent to find a reduced brain response in specific areas included in the reward processing systems when expecting to receive a positive stimulus in patients with both schizophrenia and depression, supporting the conception proposal in RDoC.

In any case, RDoC also has limitations that should not be forgotten. One criticism of an applied nature refers to the fact that perhaps the measures it proposes (genetic or neuroimaging analyses) are not yet sufficiently developed to offer reliable or clinically relevant results. A more nuclear problem is the emphasis on the biological aspect of mental illnesses, forgetting other essential aspects. Epistemology is the branch of Philosophy that deals with the character of knowledge; German Berrios, Full Professor of epistemology of psychiatry at Cambridge University states that psychiatry, insofar as it seeks to treat diseases of the mind, is a mixed and interdisciplinary discipline , rooted in both experimental and social and humanistic sciences. Its object of study is, therefore, hybrid and includes both biological and cognitive aspects that cannot be understood apart from the will, emotion or cognition inherent to human beings. On a continuum between research of the mind and research of the brain, the object of study of RDoC is unbalanced.

At final, RDoC is a U.S. government initiative that will play a central role in the research of mental illness in the coming years. It has almost insurmountable epistemological and methodological limitations, limitations that will make it difficult for goal to reconfigure current diagnostic classifications. However, it also has positive novel aspects, and we predict that it will provide knowledge that will allow us, in the medium term deadline, to optimize the treatment of people with psychiatric disorders.