IntroductionLatest classifications led to an inflamed debate urging for change or validation in the way personality disorders are classified. The placement in psychiatric classifications of several personality disorders, particularly Borderline Personality Disorder (BPD), is also a matter of discussion.Objectives and aimsThe present work aims to question BPDs place in classification alongside with other personality disorders, rather than focusing on the algorithms used to classify it. The authors review updated literature on core features of the disorder collected from online scientific databases.ResultsStudies reveal that the stability of the diagnosis of BPD over the longer term is less than what standard general definitions of personality disorders would appear to require. It is a chronic and debilitating syndrome with severe functional and psychosocial impairment that remain relevant when comparing to other personality disorders. Additionally, these measures show further declines over time in spite of improvement in psychopathology, in contrast to what happens with other personality disorders. Several misconceptions may have led to the placement of BPD on former axis II, namely being a direct consequence of trauma and merely explained by environmental factors. However, recent research on heritability shows the contrary and several neurobiological markers suggest it has got a nature of its own.ConclusionBPD is probably the most studied and validated personality disorder and has substantially greater empirical basis, clinical significance and public health implications, being both enduring and distinct from other personality disorders. We suggest the placement of BPD as major psychiatric disorder in classifications.Disclosure of interestThe authors have not supplied their declaration of competing interest.

IntroductionThere is growing evidence of the importance of nutrition in mental disorders. Gut microbiota, influenced by environmental factors such as diet and stress, has been proposed as one of the players on a dynamic called gut-brain axis, which is thought to have an influence on behaviour and mental health.Objectives and aimsTo summarize recent evidence on the topic, and its potential role in psychiatric interventions.MethodsThe authors review updated literature collected from online scientific databases.ResultsThe development of the brain itself has been shown to be influenced by the gut microbiome. Research demonstrates that the composition of the microbiota has influence on behaviour through neuroendocrine and other neuroactive messengers production by the bacteria within the gut lumen. Studies in germ-free animals, animals exposed to bacterial infections, probiotic suplements or antibiotic drugs suggest a role for the gut microbiota in the regulation of anxiety, mood, cognition and pain. The gut microbiome has been implicated in brain disorders including anxiety and depression, multiple sclerosis, Alzheimer's disease, Parkinson's disease, and autism.ConclusionsThe treatment of mental disorders is usually based on pharmacological and psychotherapeutic interventions, and little attention is given to dietary interventions. The emerging field of research focused on the human microbiome suggests an important role for the gut microbiota in influencing brain development, behaviour and mood in humans, and points new strategies for developing novel therapeutics for mental disorders.Disclosure of interestThe authors have not supplied their declaration of competing interest.