K
if the first human pair had not sinned sickness and death would not exist....yes many life choices will cause some sickness,aswell as our environment we live in will impact on our health....and yes satan can influence our mental state(if we allow)But it is sin itself which has brought sickness and death to humans.Satan is the ruler of this world at present...and not until god puts him into the abyss and then finally the lake of fire....and then sickness and deathwill be no more.