What can cause trouble concentrating and memory loss? drug and alcohol free my whole life . it's getting progressively worse. i have near-syncope

Depression?: Depression can impair concentration. Although it shouldn't cause memory loss per se, it often causes apathy (lack of interest), which might mean less things to remember. Also, are you taking any prescription meds that might impair memory? If the near-syncope is not caused by medication, you may need to be checked for an adrenal problem.

Important question: There are many possible causes. You may have a medical or neurological problem. Please see a primary care doctor who can do a good evaluation and guide your treatment.