Animal models of depression

Animal models of depression are research tools used to investigate depression and action of antidepressants as a simulation to investigate the symptomatology and pathophysiology of depressive illness or used to screen novel antidepressants.Major depressive disorder, also called 'clinical depression' or often simply 'depression', is a common, long-lasting and diverse psychiatric syndrome that significantly affects a person's thoughts, behavior, feelings and sense of well-being. Symptoms include low mood and aversion to activity. Depressed people may also feel sad, anxious, empty, hopeless, worried, helpless, worthless, guilty, irritable, hurt, or restless. They may lose interest in activities that once were pleasurable, experience loss of appetite or overeating, have problems concentrating, remembering details, or making decisions, and may contemplate or attempt suicide. Insomnia, excessive sleeping, fatigue, loss of energy, or aches, pains, or digestive problems that are resistant to treatment may also be present.Antidepressant screening tests, not like the models which can be defined as an or a particular state of an organism that reproduces aspects of human pathology, provide only an end-point behavioral or physiological measure designed to assess the effect of the genetic, pharmacological, or environmental manipulation.Certain types of human depression are precipitated by stressful life events, and vulnerable individuals experiencing these stressors may develop clinical depression. Consequently, the majority of animal models of depression are based on the exposure to various types of acute or chronic stressors.