A category of psychological conditions characterized by persistent feelings of sadness, hopelessness, and a loss of interest or pleasure in activities, significantly impacting an individual’s daily life. These conditions, as understood within the framework of introductory psychology, encompass a range of specific diagnoses distinguished by their severity, duration, and specific symptom presentation. Major features include changes in appetite or weight, sleep disturbances, fatigue, difficulty concentrating, and, in some cases, thoughts of death or suicide. For example, Major Depressive Disorder is diagnosed when an individual experiences five or more of these symptoms during a two-week period, with at least one of the symptoms being either depressed mood or loss of interest or pleasure.
Understanding these conditions is crucial for psychological professionals, as they represent a significant source of suffering and impairment for affected individuals and a substantial burden on public health systems. Knowledge of diagnostic criteria, etiological factors, and effective treatment strategies is essential for accurately identifying and addressing these mental health challenges. Historically, perspectives on the etiology of mood disturbances have evolved from primarily focusing on psychological factors to incorporating biological and social influences, leading to more comprehensive and effective approaches to intervention.