People who feel hopeless and helpless to escape stressful situations have higher levels of stress hormones in their blood.
Does it say they have higher levels of stress hormones because they do not know how to escape stressful situations, they feel helpless in the face of such situations?
The people who feel hopeless and helpless to escape stressful situations are the same people who show higher levels of of stress hormones in their blood.
Of course, we can logically deduce that the stress hormones are in existence because those people are stressed both by the situation they find themselves in and also because of their inability to escape that situation, but the sentence does not actually say that.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.