If something is disturbed, it's been moved or changed — it's not positioned or functioning the way it usually does. Traveling across the globe gives many people disturbed sleep patterns.
If your younger brother has been snooping in your room, the only evidence might be the disturbed items on your desk — maybe he rifled through your diary and left it in a different spot. When people are described as disturbed, it means they're troubled emotionally. The word comes from the Latin disturbare, "throw into disorder," and its root turba, "turmoil."