Understanding the Difference Between Depression, Anxiety & Stress:
By Lucas Stoltz
What is Stress & Anxiety?
Both stress and anxiety are emotional responses. Stress is however caused by an external trigger. Perhaps a work deadline, a fight with a loved one, a recent change in health or finances, etc. Folks under stress usually experience mental and physical symptoms, such as irritability, anger, fatigue, muscle pain, digestive troubles, and difficulty sleeping.
Anxiety, on the other hand, is defined by persistent, excessive worries that don’t go away even in the absence of a stress trigger. In the sight of anxiety, folks can experience symptoms such as insomnia, difficulty concentrating, fatigue, muscle tension, and further irritability. Therefore, excessive stress is what leads to anxiety.

Anxiety in relation to Depression
Anxiety and depression are different, unlike the relation between stress & anxiety. Yet, anxiety and depression can also overlap. The symptoms of depression may be a low mood, slowness, despondency, suicidal thoughts, feelings of hopelessness, etc. With anxiety, there’s fear, tension, restlessness, jitteriness, perhaps a sense of being on edge. Those are the contrasts.

Consider the Overlap
Murray notes three reasons;
1) they are both connected to the same brain area, so if that part of the brain goes wrong, then you can expect both depression and anxiety to come out of it.
2) they can both result from the same events in life. For example, if somebody suffers abuse, then very obviously they can get depressed about that, but also anxious about the future and meeting people—especially authority figures.
3) one can cause the other. If you have anxiety—your body is all keyed-up, running on high-revolutions, and you’re very tense—that eventually wears you down and wears you out and you can slump into a depression. So, one can cause the other, and it can go both ways.

Summary
So this brief article is to distinguish the difference between depression, stress and anxiety in order to understand why they overlap so that we don’t treat the wrong thing, and sometimes we need to treat all three things.
For more helpful resources, check out:
David Murray – Christians Get Depressed Too & Why Am I Feeling Like This