The Holy Quran says:
"Who created me, and it is He Who guides me;
"Who gives me food and drink,
"And when I am ill, it is He Who cures me;
"Who will cause me to die, and then to life (again);
"And who, I hope, will forgive me my faults on the day of
Islam believes that God not only created this world but also He is sustaining the world.He is not only controlling major events but also minute events in the universe.Life ,death , illness and cure is all in His hands.
This dogma never means that we don’t go for treatment which is proved by the life of Messenger of Allah ,but I believe psychologist would understand the implication of believing in a super natural power.This belief boost a patients self confidence and fastens patients recovery. Moreover a sense of not being alone saves the patient from depression which is the worst outcome of almost every chronic or severe illness.There are certainly many other benefits which are impossible to mention here.