For the past four weeks, 20-year-old Odessa has been feeling lethargic and worthless. Her friends are worried because she no longer shows interest in her normal social activities. It is very likely that Odessa is suffering from:

Major depressive disorder

Explanation:

Major depressive disorder is a mood disorder that disrupts one's daily activities characterized with depressed moods, constant relay of thoughts in the brain,  feelings of worthlessness, and reduced interest in most  normal activities e.g social activities etc.

20-year-old Odessa who has been feeling lethargic and worthless for four weeks as observed by  Her friends when she no longer shows interest in her normal social activities explains that Odessa is suffering from Major depressive disorder.