Development of depression is associated with the body's response to prolonged stress, which adversely affects the functioning of the nervous, endocrine and immune systems. Prolonged stress can lead to the development of a so-called allostatic load and reduction of concentration of brain-derived neurotrophic factor. These changes result in impairment of neurogenesis and synaptic remodeling process. This article illustrates the involvement of key mediators of allostasis such as the neuroendocrine and immune systems, in the pathogenesis of depression. The literature concerning the contribution of the neuroendocrine and immune systems to depression incidence was reviewed. Development of depression is associated with disturbance of the body's allostasis and inflammatory activation of the immune system. It leads to a chronic increase in the concentration of cortisol and proinflammatory cytokines, which results in an allostatic load. This load leads to neurodegeneration, eventually causing irreversible cognitive impairment and permanent disability. Determination of the concentration of chemokines and their receptors is an important indicator of activation of the immune and neuroendocrine systems. The activity of these systems reflects the severity of the disease and provides important information for effective antidepressant treatment.

Melatonin may be a significant marker of depression severity. Melatonin and NF in depressed patients show neuroprotective effects.

Human sexuality is contingent upon many biological and psychological factors. Such factors include sexual drive (libido), physiological arousal (lubrication/erection), orgasm, and ejaculation, as well as maintaining normal menstrual cycle. The assessment of sexual dysfunction can be difficult due to the intimate nature of the problem and patients’ unwillingness to discuss it. Also, the problem of dysfunction is often overlooked by doctors. Atypical antipsychotic treatment is a key component of mental disorders’ treatment algorithms recommended by the National Institute of Health and Clinical Excellence, the American Psychiatric Association, and the British Society for Psychopharmacology. The relationship between atypical antipsychotic drugs and sexual dysfunction is mediated in part by antipsychotic blockade of pituitary dopamine D2 receptors increasing prolactin secretion, although direct correlations have not been established between raised prolactin levels and clinical symptoms. Variety of mechanisms are likely to contribute to antipsychotic-related sexual dysfunction, including hyperprolactinemia, sedation, and antagonism of a number of neurotransmitter receptors (α-adrenergic, dopaminergic, histaminic, and muscarinic). Maintaining normal sexual function in people treated for mental disorders can affect their quality of life, mood, self-esteem, attitude toward taking medication, and compliance during therapy.

The results of this study indicate the need for assessment of CCL-5 and SDF-1 chemokines levels, as they are likely markers of developing depression. Early measurement of these chemokines levels may be helpful in choosing the best pharmacotherapy.

Our study has shown the need for determination of proinflammatory interleukins which are considered as biomarkers of personality disorders and generalized anxiety disorders.