Imagine what it would feel like if one of your senses went into overdrive; if suddenly you could smell not just your coworker's coffee in the next cubicle, but also her shampoo, her toothpaste, and the dirt on her shoes. Or if the lights in your office felt like rays of the sun burrowing into your eyes. Or if your ears were bombarded with the clicking of the keyboard, a car alarm beeping on the street below, the sputtering of the air conditioner unit, your boss's chewing gum, and a coworker tapping his pencil three desks away.

This is what life feels like for someone with sensory processing disorder (SPD). And for most people who have this condition, it's not just one sense that has gone haywire, but several.

SPD is a condition in which the brain has trouble processing the feedback it receives via the senses. Lights and colors are too bright, sounds are too loud, smells too harsh, and tactile sensations are too intense.

Rachel Schneider, the blogger behind Coming To My Senses, was diagnosed with SPD in 2010 at the age of 27, after decades of feeling like she was losing her mind. In this note on her Facebook page, she describes what an average social scene feels like to a person with SPD:

"What are you supposed to tell someone when they ask if you're ok? There are no real words one can assemble on the spur of the moment, casually, to say, 'No, I'm not ok. I was just diagnosed with SPD, and this really is a lovely party, but my brain is reeling. The dog won't stop circling my legs and the squeak of the cooler behind me is making me antsy. No, because there are at least 20 distinct voices that I cannot track out here in your beautiful boutique back yard bursting with peach trees, and there are too many blades of grass, and I can't sit here when the air doesn't move past my skin and the sound of meat sizzling on your grill is painful.' And so I sit inside, a redundancy, for the millionth time of my life, wondering who will notice and what they will secretly say later about the unnaturally quiet, agitated-looking girl who has disappeared from the party."

Not everyone who has SPD experiences it the same way. Schneider is hyper-sensitive to sights and sounds. For someone else who is sensitive to touch, even the softest fabrics may feel like sandpaper and the most gentle of hugs may feel like too much of a squeeze.

The biggest challenge for people who suffer from SPD is that the condition is not currently recognized as an official disorder. That makes it difficult to diagnose and nearly impossible to get treatment and services. Because many children with autism spectrum disorder also suffer from SPD, it's often lumped in with that disorder. But there are many children and adults who don't have autism symptoms, and it's this group that tends to get lost in the shuffle.

Another confusing issue that swirls around SPD is that while some sufferers have over-responsive senses, others are under-sensitive, making them crave stimulation in one or more of their senses. Meanwhile, others are over-responsive in some senses and under-responsive in others. In other words, the symptoms for SPD vary widely.

Fortunately, some new research from pediatric neurologist Elsa Marco at the University of California, San Francisco, may help shed light on the causes and effects of SPD. Through several studies using magnetic resonance imaging, Marco has identified measurable differences in the brain structure of people with SPD. Specifically, she has found differences in the areas of the brain involved in processing visual, aural and touch information. One of Marco's studies also found significant differences in the brain images of children with SPD when compared to those who had autism. This is an important step in classifying SPD as its own condition, but that classification may still be a few years away.

For now, children and adults who suffer from SPD can find support via communities like the one Schneider has built on her blog and Facebook page as well as others like the SPD Foundation and SPD Connect.

As Schneider puts it in an interview with the BBC, the goal at this point for people with SPD is to connect and share information about symptoms, research and treatment options.

"There are a lot of psychological conditions affiliated with this, because for so long, the sentence in your head is: ‘I can’t do this, what is wrong with me, I can’t do this, everybody hates me, I’m embarrassing, life is painful and difficult, I can’t do this,'" Schneider noted. "So I’m trying to change the dialogue to: ‘It’s a little bit difficult, you have to change how you do things … but yes, you can.’'

What is sensory processing disorder?
For someone with SPD, even the most ordinary situations may feel overwhelming and chaotic.