You misplace your keys, waver between work assignments and YouTube, and daydream during conversations. Some of it’s normal—life can get pretty hectic—but how do you know if you have a more serious problem? For adults who have attention deficit hyperactivity disorder (ADHD), this chronic inattentiveness becomes debilitating.

“We see an influx of adults being diagnosed around age 38,” says Timothy Wilens, MD, an associate professor of psychiatry at Harvard Medical School. “That’s right around the time people start multitasking more, juggling jobs, families, a home, and other personal obligations—and problems focusing and staying alert seem to get worse,” he says.

But not everyone who slacks on work or forgets appointments has ADHD; there are plenty of other reasons you may be losing focus. Here are five things that could be sucking your attention span dry. Plus: When you should consider seeing your doctor. View the Slideshow