Final answer:
Psychosurgery can be considered as a last resort treatment for severely depressed patients unresponsive to drug therapy, but it is controversial and carries risks.
Step-by-step explanation:
Dr. Chen's treatment plan of recommending psychosurgery for the severely depressed patient who is unresponsive to drug therapy can be considered as a last resort when all other options have been exhausted. Psychosurgery, also known as neurosurgery for mental disorders, involves surgical intervention to alter or destroy certain brain areas to alleviate symptoms of mental illness. While it has been used in the past for severe cases, it is important to note that psychosurgery is controversial and carries risks, including potential changes in personality and cognitive function.