Microbiome in psychiatry: where will we go?

Excerpt

Will the current standard routine diagnostics (e.g., blood count, electrolytes, ECG, cMRT) be combined with human genotyping and microbiome analysis in the future to set up an individual pharmacological and psychotherapeutic treatment program or nutrition plan (e.g., use of probiotics) or, as a last resort, to initiate a fecal transplantation therapy? What will be the role of the microbiota in the biopsychosocial model of the genesis of mental illnesses tomorrow, and how will its individual composition and function influence our therapeutic decisions? Will we take the decisive step to resolve the dilemma of trial and error in the search for the right drug for an individual patient with the help of the microbiome, a step that pharmacogenetics alone currently does not allow yet? Today, we indeed look with astonishment at the research on the life of the most diverse microorganisms in and on the human body—especially in the intestine—, findings that grow at a breathtaking speed. A major cause of this rapid growth is the advance in gene analysis techniques beginning in the 1980s, and especially in the implementation of more recently introduced molecular genetics approaches (e.g., next-generation sequencing). Only then it was possible to detect the overwhelming amount of non-cultivatable microorganisms and their complex activities, which go far beyond the previously expected main task of supporting the digestion or of providing individual vitamins. The mere knowledge of the presence of trillions of microorganisms in the gastrointestinal tract, with a total genome of 9,879,896 genes [1], relativizes the human host as a single being and makes him part of a hybrid phenomenon in close association and interaction with these other creatures. Obviously, the composition of the microbiota is changing continuously throughout the life, and contrary to previous positions it can be assumed that the development begins already before birth. The composition of the microbiota is determined by a variety of factors, but most decisively by the genetics of the host [2]. …