Depression unveiled: Insights into etiology and animal models for behavioral assessment, exploring the multifactorial nature and treatment of depression

Over the past century, significant shifts in daily living have led to an increased prevalence of mental disorders, often linked to hormonal imbalances. Among these, anxiety and depression stand out as prevalent diagnoses, particularly in industrialized nations. Depression, according to the DSM-5, is a heterogeneous condition that affects emotional, cognitive, and physical functioning, with symptoms including insomnia, sexual dysfunction, and weight changes. Cognitive theories of depression highlight its impact on judgment, decision-making, thinking, and focus. Depression's multifaceted nature means that no two patients experience identical symptoms, risk factors, or treatment responses. The COVID-19 pandemic has exacerbated mental health issues, with social isolation, restricted contact, and altered daily routines contributing to increased anxiety and depression, especially among adolescents and young adults. The pandemic's psychological toll underscores the need for effective treatment strategies for mental disorders. The physical manifestations of major depressive disorder (MDD) are associated with a heightened risk of developing various medical conditions, including metabolic disorders, cardiovascular disease, stroke, epilepsy, and dementia. This review provides a comprehensive exploration of depression and anxiety, covering their different types, epidemiology, potential causes, diagnostic criteria, and available treatment options. It delves into the role of pharmacological interventions and examines recent advancements to enhance therapeutic outcomes. Additionally, the review assesses the therapeutic potential of drugs, offering insights into their efficacy in treating these complex mental health disorders. By targeting the multifactorial etiology of depression through drug repurposing and new drug development, researchers aim to enhance treatment efficacy and achieve better outcomes for patients with depression.