Possibilities of using laboratory biomarkers for the objective diagnosis of depressive disorders

Abstract

Objective: to assess the possibility of using laboratory biomarkers to objectify psychopathological disorders in patients with depressive spectrum disorders (RSDs).Patients and methods. The investigation enrolled 63 patients (mean age, 31.7±8.9 years) with new-onset RSDs of different etiologies. Group 1 included 21 patients with a mild to moderate depressive episode (DE); Group 2 consisted of 42 patients with neurotic depressive disorders (adjustment disorders). The severity of anxiety and depression was assessed using the Hamilton Depression Rating Scale, the Hamilton Anxiety Rating Scale, and the Hospital Anxiety and Depression Scale. In addition, the investigators studied laboratory parameters: the levels of cortisol, homocysteine, prolactin, vitamin B12, cortisol, interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in serum and platelet serotonin. They also estimated changes in the most significant laboratory parameters in 31 patients with depressive disorders: in 15 with DE and in 16 with neurotic depression who had received 4-week monotherapy with agomelatine 25 mg/day.Results and discussion. The differential diagnosis of psychopathological disorders based on the clinical and psychopathological method and psychometric assessment of the patient's condition was shown to be difficult. It was established that the objectification of these disorders using known laboratory biomarkers (cortisol and platelet serotonin) did not give an unambiguous answer. At the same time, the assessment of immunological parameters (the levels of proinflammatory cytokines, such as IL-6, TNF-α) can help to solve this problem. The investigation also demonstrated that the use of non-monoaminergic antidepressants (MT1/MT2-type melatonin receptor agonists) contributed to the reduced level of proinflammatory cytokines, which opens up opportunities for finding new therapeutic approaches to treating RSDs. Conclusion. Usage of biological markers may contribute not only to improvement in the accuracy of mental disorders diagnosis but also to the development of new treatment approaches. Simultaneously, the selective use of individual biological markers (biochemical, metabolic, immunological, etc.) is not very informative; therefore, their comprehensive assessment is required.

Keywords

• depressive spectrum disorders
• diagnosis
• diagnosis objectification
• laboratory parameters
• cytokines