I wouldn't rank it as the worst, though it's definitely far below average overall.
If you judge by where people are the most depressed, the worst states are Wyoming, Alaska, and Montana, which have the highest suicide rates. If you judge by where people are poorest, it's MS, LA, and NM. If you judge by your chance of being murdered, the worst are MS, LA, and AL. By life expectancy, the worst are MS, AL, and WV. By income, the worst are MS, WV, and AR. By incarceration, it's LA, OK, and MS. By educational attainment, the worst are WV, MS, AR. By lowest credit scores, the worst are MS, LA, and AL.
So, I'd say Mississippi is probably the worst, overall. The best, using the same measures, would probably be Massachusetts.
Kind of interesting that liberal places do so much better than conservative ones, don't you think?