Final answer:
For a major depressive disorder diagnosis, symptoms must be present for at least two weeks, which is option (B). This duration helps to distinguish serious, persistent depression from temporary mood changes.
Step-by-step explanation:
To receive a diagnosis of major depressive disorder (MDD), an individual must exhibit symptoms for a minimum duration. According to the Diagnostic and Statistical Manual of Mental Disorders, a person must have experienced a severely depressed mood and have other symptoms such as loss of enjoyment in activities, changes in appetite and sleep schedules, difficulty concentrating, and feelings of worthlessness for at least two weeks. This period is considered sufficient to distinguish between temporary mood fluctuations and a persistent state that could constitute MDD.
Moreover, it's essential to acknowledge that while the duration of symptoms is a vital criterion, the severity and impact on daily functioning are just as crucial for the diagnosis. The symptoms must lead to significant distress or impairment in social, occupational, or other important areas of functioning. Additionally, these symptoms should not be attributable to the physiological effects of a substance or another medical condition. It's also worth noting that MDD is a complex illness with potential genetic and environmental contributing factors, and it's a leading cause of disability worldwide.
(B) 2 weeks. An individual must experience symptoms for at least this duration for an MDD diagnosis.