1. Tech overload. With Blackberrys, laptops, iPods and TVs -- it's no wonder we're distracted! The more multi-tasking you do, the harder it is to stay focused on any single task -- that's a given. But see a doc if you're constantly distracted from important tasks.

2. Lack of sleep. If you're missing out on getting enough sleep (7-8 hours), you're probably irritable, foggy and unfocused. See a doc if you have sleep problems, wake up unrefreshed, or can't seem to stay alert. You could have a sleep disorder.

3. Poor job satisfaction. Everyone's unhappy at work sometimes, and a hectic office or boring project can make it difficult to focus. But if you consistently get distracted or have severe procrastination issues, you may need to see a doctor.

4. Too much stress. Stress takes a toll on concentration. Relaxing or meditating can help you block out distractions, but if you have other mood issues related to stress (like anxiety or depression -- they often go with ADHD), you should see a doc.

5. Not enough exercise. Working out regularly keeps your mind sharp and increases learning and memory. But if you have a hard time sitting still or you self-medicate by exercising too much just to stop being restless, you should see a doc.