Depressive disorders have a diverse clinical presentation. Some of them can be modeled on animals. One of the symptoms observed in animals with depression is anhedonia – a reduced interest in something, a lack of pleasure in positive symbols. But depressed mood, loss of energy, weight, insomnia, hypersomnia , psychomotor agitation, feelings of hopelessness and uselessness, suicidal thoughts cannot be recorded in animals.

Cognitive impairments can be observed in both animals and humans. Patients suffering from depression have functional impairments, a deficit in social cognition, and a low speed of information processing. These functions can be studied in animals as well.

Cognitive dysfunctions may not be normalized with modern psychotropic drugs. Flucostin improves memory function more than desipramine and amitriptyline. Many authors believe that cognitive function is not from affect alteration, although serotonin reuptake inhibitors (SSRIs) improve mood and enhance memory.

Cognitive stimulants can be considered drugs in the treatment of depression. A study of donesepil showed an improvement in the neuropsychiatric symptoms of dementia and a decrease in depression, as measured by special scales. Patients with depression, when taking donesepil after a course of monoaminergic antidepressants, noted improved memory and neuropsychological functioning.

It has been experimentally proven that an increase in cholinergic and serotonergic transmission influenced the neuroplasticity of the brain and altered the synchronicity between the amygdala and hippocampus .