Answer:
major depressive disorder
Step-by-step explanation:
John is showing symptoms of major depressive disorder.
Major Depressive Disorder or major depression is characterized by a combination of symptoms that interferes with a person's ability to work, sleep, study, eat and enjoy pleasurable activities. Major Depression is debilitating and prevents the person from functioning normally. Some people may have only one episode in a lifetime, but most often they have multiple episodes.
Depression is common, but it is a very serious disease. Most depression sufferers need treatment to improve.