Loss of interest in life can have various causes, just like most other symptoms. Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.
Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms. In order to diagnose loss of interest in life, we could:
Do you have an overall loss of interest or pleasure in activities that you once enjoyed, due to depression or unknown reasons? If you are still interested but can't enjoy these activities due to fatigue, poor health, lack of time, or stress, answer "No".
Possible responses:→ Don't know / I never had many interests
→ Slight loss of interest
→ Moderate loss of interest
→ Complete or almost complete loss of interest