From the subject given in your question, it sounds like you are researching and writing on a medical and possibly psychological topic. Before going any further, let me advise you to save your introduction for the very end. I find it is much easier to write an introduction when I've already written the body of the paper. This way, I'm "introducing" something I'm very familiar with. It tends to make the introduction more natural and not sound forced. Without knowing the content of your entire paper, it is difficult to provide specific examples for an opening paragraph, but you could consider the following as advice that should be applied to any paper.
In a research paper of considerable length (as in, more than a 5 paragraph essay), it is not uncommon to have several paragraphs serve as the introduction. I typically advise students to open with something that helps frame some background information as well as sparks interest in the overall topic of the paper. In this, you could summarize a true story that you read about in your research. You could also provide startling facts and statistics about the frequency of patient abandonment with the deeper intention of showing why this topic is important today (or why many people are unaware of this as a problem). If there are any vocabulary words which are rare for an educated audience but will used frequently in the paper, the introduction is not a bad place to provide some background knowledge to help pre-educate your audience using some of the language the paper will utilize.
Of course, remember, that ultimately, your introduction must eventually provide your concrete thesis statement and an idea of the organization method your paper will employ. It is easiest to lead up to this and make it the final paragraph of the introduction section, especially if you lead with a few paragraphs that act as a "hook."
Remember not to make the paper at all about you. In fact, remain completely objective. It is possible to show why you are interested in a subject without directly stating, "This subject interests me because..." It is also possible to show why you believe a subject is important without directly stating, "This subject is important because..."
The link below provides a few other introduction tips that might be helpful here.