The condition affects an estimated 280 million people worldwide.
He said: “Jesus asks us all ... to be missionary disciples. Are you ready?”
He made the appeal in his prayer intention for September.
In an accompanying video, the pope said that the Church ‘always is in crisis, because she’s alive.’
Pope Francis has asked people to pray throughout June for young people preparing for the life-long journey of marriage.
Pope Francis is inviting Catholics around the world to pray this month for people risking their lives by standing up for fundamental rights.