Bipolar disorder (BD) is a severe mental illness characterized by recurrent episodes of mania, depression, or mixed states. The lifetime prevalence of bipolar disorder across the spectrum is estimated at 2–4% in the general population and is the sixth leading cause of disability worldwide. Cannabis is the most commonly used substance after alcohol and tobacco. Its use increased from 4 to 9.5% between 2020 and 2022, and the prevalence of cannabis use disorders rose from 1.5 to 2.9% over the same period. Among patients with mental disorders, the most common reason for using cannabinoids is to try to alleviate their underlying illness, which is probably achieved in the initial stages of using this type of psychoactive substsance. However, its influence on the course and prognosis of the disease in the long term remains insufficiently studied, which requires a detailed investigation of this problem. For our study, in the period from 2020 to 2022, we selected 104 patients with a diagnosis of bipolar disorder (F31) with a plant cannabinoid addiction syndrome (F12) with a disease duration of more than five years, and the onset of cannabinoid use was noted already amid an established diagnosis of bipolar disorder. The average age in the group was 39 ± 3 years, the distribution by sex was 47% (p < 0.005) — men, 53% (p < 0.005) — women. The study showed that the beginning of the use of plant cannabinoids in a context of BD generally worsens the mental state of patients and, in terms of prognosis, is unfavorable for the course of the disease. This conclusion is confirmed by the complete absence of remission in 2% of patients with an interval of 6 months from the beginning of the study of these patients, the severity of the condition in general, rapid change in the phases of bipolar disorder, and the need to prescribe higher doses of a pharmacological drug. A change in the labor activity of patients was noted — in the primary study we did not register non-working patients; in the study spaced 6 months apart, there were 5% of them; the level of qualification of the work performed in the group as a whole also decreased (employed in highly skilled labor in the primary study — 31%, in the study of this group of patients, this figure decreased to 25%. The motive for using plant cannabinoids was an attempt to alleviate their mental state (73%), 20% of patients noted the motive as “an attempt to experience pleasure”, 7% of patients could not explain the reason for starting cannabinoid use.

Currently, the relevance, and at the same time the interest of researchers, to such a psychiatric disease as post-traumatic stress disorder (PTSD) has greatly increased. Socio-economic, environmental, anthropogenic, epide¬mic events can become the very causative factor of sufficient intensity that will trigger the pathogenesis of PTSD. In the era of globalization, the social significance of this disease is higher than ever. If the diagnosis, treatment and rehabilitation of victims are not carried out in a timely manner, then the likelihood of chronic PTSD symptoms with a gradual pathological transformation of the patient's personality becomes high. These pathological personality changes are not only a heavy burden for each patient and his environment but also additional healthcare expenses for rehabilitation. At the moment, various treatment regimens have already been developed, but none of them is universal and comprehensive. New therapeutic approaches are needed that can provide patients with a stable remission in the shortest possible time preventing their maladjustment in society. In addition, the problem of compliance in such patients, as well as the presence of resistant forms of PTSD comorbid with other psychiatric conditions is quite acute.

Currently, the possible role of intestinal microorganisms in the etiology and pathogenesis of mental illness is being actively studied all over the world. Every year the number of studies is steadily increasing, however, in the Russian-speaking environment, an awareness of this issue and the number of extensive reviews of scientific literature still remain at an insignificant level. The aim of this study is to review and systematize the scientific literature and clinical studies on the impact of the intestinal microbiome on the etiology and pathogenesis of depression, schizophrenia, autism spectrum disorders, Alzheimer's disease, bipolar disorder, and obsessive-compulsive disorder. The actual studies were conducted in sick volunteers and animal models using different approaches: comparison of the composition of the gut microbiota between affected subjects and controls; observation of behavioral changes in affected subjects after administration of pathogenic intestinal microbiota or probiotics. Definite regularities in the change in the qualitative and quantitative composition of the taxonomic units of various microorganisms were revealed.