Justified text used inappropriately can cause serious readability problems. With simple justified text the uneven variation in spacing between words makes the text more difficult to read because, instead of moving smoothly along the line, the eye has to jump from word to word. For people with certain disabilities such as dyslexia the problems can be serious; justification can interfere with their ability to understand the text at all.
Used correctly, italics can enhance copy by adding both meaning and style. However, a little care needs to be taken to ensure readability, correct semantics and the avoidance of potentially serious page layout problems.