It’s fashionable these days to declutter, downsize and strive for simplicity. Whatever you call it, most of us find it hard to toss out junk and embrace a minimalist lifestyle. Why? Blame it on your inner hoarder.

Granted, most of us aren’t pathological hoarders and won’t wind up on TV with stuff piled to the rafters. But we may hang on to more possessions than we should and have trouble emptying drawers, tossing papers and parting with “treasures” that slipped off our radars long ago. Here’s a look at the psychology behind hoarding, how it differs from collecting and ordinary clutter, and how to keep untidiness to a minimum.

Hoarding 101

You’ve probably watched TV shows like “Hoarding: Buried Alive,” a weekly journey into the troubled lives of people who stuff rooms so full of junk, including garbage and even animals, that no one can walk through. This is called hoarding disorder, and it’s a form of mental illness.

The American Psychiatric Association’s DSM-5 (Diagnostic and Statistical Manual) estimates that 2 to 6 percent of Americans suffer from this compulsive need to acquire things. It outlines six criteria that characterize the disorder, including extreme psychological distress at the thought of parting with possessions, excessive clutter that may cause health and safety issues, and impaired ability to function normally.

Hoarders also can suffer from feelings of isolation, loneliness and depression, and may face family and marital issues, as well as health, legal and financial problems (many hoarders go into debt and are sometimes evicted from their homes).

animal hoarding Animal hoarders cram unusually large numbers of pets into their homes that they can’t feed or care for properly. (Photo: Stefan Körner/Wikimedia Commons)

Brains in pain

Why do people let material things take over their lives? Some hoarders claim they’re hanging onto stuff that may be useful or valuable down the road. Others can’t decide what to do with items so they keep them. Or they become obsessively attached to things that seem irreplaceable or highly unique or necessary to keep certain memories alive.

Whatever the reason, research suggests it may boil down to different brain wiring. In a 2012 study from Yale School of Medicine, hoarders and non-hoarders were asked to decide which items to discard and which to keep. Some items belonged to them and some belonged to the researchers.

Hoarders showed significantly more activity than non-hoarders in two brain regions when deciding about their own possessions and much less activity when considering the researchers’ possessions. These areas of the brain — the anterior cingulate cortex and insula — are linked to feelings of conflict and pain. The more the hoarders struggled to decide about possessions, the more these areas lit up.

What about collectors?

Maybe you have a display of 1930s salt and pepper shakers. You actively visit antique shops and are quick to buy more sets whenever you find them. Or you’ve amassed a museum-worthy stockpile of hedgehog figurines after falling in love with the quirky creatures when you were 7.

Are you a hoarder? Probably not. More likely, you’re a collector.

collectors differ from hoarders Collectors may amass some pretty outlandish things, but unlike hoarders they usually lovingly display their collections and derive immense satisfaction from them. (Photo: Will Keightley/flickr)

Yes, they share similarities. Like collectors, hoarders often fixate on one type of item, and in both cases some of the same brain centers may be stimulated. But there are also key differences.

For one thing, some hoarders compulsively stockpile random heaps of completely useless garbage, like unmatched socks, broken appliances, dead bugs, burnt-out light bulbs and measuring scoops from laundry detergent boxes. Check out this fascinating list of items people admit to hoarding. Hoarders are usually ashamed of their junk piles, which severely hamper their lives, and often try to hide them from others by withdrawing socially.

Collectors, on the other hand, are intensely passionate about the items they amass and take pride and pleasure in their collections. They may feel a sentimental attachment to these items because they represent good memories from childhood (think Beanie Babies) or they embody areas of special interest (like fossils or art).

Unlike hoarders, collectors also usually keep their displays well organized and often proudly show them off to anyone who expresses interest. In addition, many collectors trade or sell parts of their collections without feeling distressed.

Of course, some collectors may cross over from normal hobbyist into hoarder territory. Call them extreme collectors. If your zeal for collecting starts to affect your job, personal relationships or pocketbook, or the items you bring home begin taking over your house, or you can’t part with even a single object, you may have entered the hoarding zone.

Clutterers and pack rats

clutter related to sense of identity Most of us live with some clutter, and the things we hang onto are often linked to our sense of identity. (Photo: Doug Belshaw/flickr)

Unless you’re a true neat freak, you probably have a few perpetually messy hot spots in your home — a closet filled with old clothes you mean to donate, boxes of timeworn toys in the attic, a catch-all room loaded with bargain items you have yet to use.

You’re probably not a hoarder, but how you view possessions may fuel this kind of shopaholism and domestic disarray. A 2011 study in the Journal of Consumer Psychology found that things you acquire and hold onto are most likely connected to your sense of self-worth.

The trick to clutter-free and lower-consumption living may boil down to a little soul searching about the things that feed your identity. In other words, you may hang onto your grandpa’s tackle box because it reminds you of treasured summers spent fishing together. Such a precious family memento is definitely worth keeping.

However, it may be time to part with or stop buying things that don’t define who you are or hold sentimental value. Yes, that includes the stack of 10-year-old magazines on the corner table, your bank statements from 1990 and the closet full of unworn shoes you routinely buy on blowout sales.