I have a theory. It is that many of the people who are taking anti-depressant drugs, who feel they are so depressed that they cannot come out of it without medication could instead take one simple dose of – HOP and be cured:

13 May the God of hope fill you with all joy and peace in believing [through the experience of your faith] that by the power of the Holy Spirit you will abound in hope and overflow with confidence in His promises. Romans 15:13(AMP) 

13 I pray that God, the source of hope, will fill you completely with joy and peace because you trust in him. Then you will overflow with confident hope through the power of the Holy Spirit.. Romans 15:13 (NLT)

We see in both of these translations that there are two things needed to infuse HOPE in us: joy, and peace. Both of which must be given to us by God. With these two ingredients, our faith takes on a new dimension; we lean on the power of the Holy Spirit and as a result our life is not only infused with HOPE, but it also "overflows with confidence in His promises"!  Unless we sign up for the whole package it’s like needing a multi-vitamin and only taking Vitamin C. While vitamin C is good for you, it won’t provide the necessary nutrients for your entire body. 

God has engineered our physical bodies to need green, red, and yellow vegetables. He has engineered our spiritual body to need faith, joy, peace, and hope. After all, our faith can only produce substance from the things that we "hope for" (Hebrews 11:1). Be encouraged today:

Why art thou cast down, O my soul? and why art thou disquieted in me? hope thou in God: for I shall yet praise him for the help of his countenance. Psalms 42:5 (KJV)