The improvement of drug therapy for a number of neuropsychiatric diseases requires the search for new directions of action in comparison with those currently used. Most of the drugs used affect molecular targets that modulate interstructural (interneuronal) interactions. Influencing the deeper processes of synaptic and neuronal homeostasis may be a new direction in the treatment of these diseases. This review examines the mechanisms of homeostatic plasticity of synaptic transmission and electrical excitability of neurons, which balance each other and stabilize the functioning of neurons and neural networks. The first type of homeostatic plasticity is regulated by the intracellular Ca2+ concentration and the activity of protein kinases, and the second one - by membrane density of voltage-dependent ionic channels. Analysis of literature data shows that alterations in some neuro-psychiatric diseases reveal disorders of homeostatic plasticity more often in terms of monodirectional alterations of synaptic impacts and neuronal electrical excitability. Thus, mainly in preclinical studies, it was revealed that stress-induced depressive disorders of behavior are accompanied by a unidirectional increase in pyramidal neurons of 2/3 layers of the prefrontal cortex of rodents, or a weakening in neurons of the 5th layer of synaptic drive and electrical excitability. Similar disorders of homeostatic plasticity were observed by other authors in pyramidal neurons of the dorsolateral prefrontal cortex in schizophrenia, depending on the prevalence of positive or negative symptoms. In chronic neuropathic pain, an increase in the excitability of peripheral neurons of the spinal / trigeminal ganglia, neurons of the dorsal horns, and cortical neurons and an increase in incoming synaptic influences were revealed. The observed disturbances were accompanied by changes in the density of ion channels in neuronal membranes. The peculiarities of the distribution and biophysical properties of voltage-dependent potassium channels allow us to consider them as a probable molecular target for the correction of disorders of homeostatic plasticity.