ABSTRACT

Major depression, also known as unipolar depression or major depressive disorder, is a main contributor to the global burden of disease. With respect to disability-adjusted life years, depression presently ranks third in the World Health Organization Global Burden of Disease study (World Health Organization 2008) and is projected to be the second leading cause of disability worldwide by 2030 (Mathers and Loncar 2006). Lifetime prevalence of the disease is 10-25% for women and 5-12% for men. Characteristic disease symptoms are depressed mood, loss of interest or pleasure, feelings of guilt or worthlessness, disturbed sleep and/or appetite, low energy, poor concentration, and suicidal ideations, which often become chronic or recurrent, substantially interfering with the

1.1 Introduction ..............................................................................................................................1 1.2 Feasibility, Purposes, and Requirements of an Animal Model of Depression .........................3 1.3 Adopting the Endophenotype Concept to Animal Models of Depression ...............................4 1.4 Conceptualizing Differences in Behavioral Analyses of Depression: What Is a Model,

What Is a Test, and What Is an Antidepressant Screening Paradigm? .....................................5 1.4.1 Discriminating between Animal Models of Depression and Behavioral Tests ............5