Effectiveness of Treatments for Major Depressive Disorder

In clinical psychology, the effectiveness of various treatments for mental disorders can greatly vary depending on several factors, including the nature of the disorder, the therapeutic approach used, and individual patient characteristics. Research has demonstrated that certain therapies tend to show higher efficacy rates for specific disorders. For example, cognitive-behavioral therapy (CBT) is frequently highlighted for its success in treating anxiety disorders.

Given this context, which of the following treatment approaches has been shown through empirical research to be the least effective for major depressive disorder, particularly in terms of long-term outcomes and symptom management?