Neurology and Psychiatry are close subdivisions of medicine. Both share several features as these disciplines study diseases of the nervous system. There are several examples in the historical context of relations between these disciplines such as the description of Alzheimer's Disease by Alois Alzheimer, a neurologist and psychiatrist, and the psychopathological descriptions of Jean-Martin Charcot the famous neurologist from Salpêtrière. However, at some point in the history these disciplines were dissected giving a powerful value to psychological and social interactions for psychiatry and only biological aspects for neurology. This approach is not convenient and is limited for both disciplines, as practically all neurological diseases courses with emotional and behavioral symptoms, and psychiatric disorders are basically a combination of social, psychological, and biological factors.

More recently, facilitated by the discovery of specific drugs developed for the treatment of mental disorders, as well as the technological innovations of novel biomarkers such as structural and functional brain imaging; the pathophysiological comprehension of mental disorders has been growing, creating a re-emergence on the relevance of biological factors in psychiatry. An example is the growing research of the neurobiology of schizophrenia utilizing brain MRI spectroscopy, where detection in the imbalance of the Glutamate system has rethought basic neurobiological aspects of the disease¹, creating interesting hypothesis on the creation of novel drugs with alternate (non-direct dopaminergic) actions. On the other hand, and lately, fMRI studies on functional neurological disorder (FND) have demonstrated neurobiological associated factors², changing the overview of the old-fashioned way of approach of this disease, previously named ‘conversion disorder', understood in the past as mainly explained by stressful events. The last version of the Diagnostic and Statistical Manual of Mental Disorders excludes the prior symptom of ‘related to psychological and stressful events' in the core clinical criteria and the name has changed from ‘conversion disorder' to FND. Furthermore, in the last years more neurologists specially those related to movement disorders and epilepsy areas are increasing their interest in research and treatment of FND, and current recommendations suggest a mixed approach by neurologists and a psychiatrists³. Lastly just to mention another example of Neurology and Psychiatry overlap, it has been described that depression and epilepsy have a bidirectional relationship. This means that depression in people without epilepsy increases the risk of developing epilepsy in the future. On the other hand, people with epilepsy (PWE) have an increased risk of developing depression compared to healthy population. Furthermore, the use of antidepressants in PWE has been associated with a better control of seizure frequency⁴.

With this background the Editorial team includes in this issue different articles approaching psychiatric and neurological diseases. García-Galicia et. al. described the cognitive features in a pediatric sample of patients with attention deficit hyperactivity disorder, finding deficits in working memory and processing speed. González-Orozco et. al., described the latest incidence of depression and suicide in Mexico. Hernández-Cortes et.al., exhibited different tables of percentiles of the third ventricle volume according to age and sex which are associated with brain aging, and finally Cacho-Díaz et.al., described the headache features associated with brain metastases.