A few years ago I went through a phase of yelling at my children for what often felt like no good reason. I was able to bribe forgiveness — a cone of mint chocolate chip can work wonders — but I was terrified I would scar my kids for life. Worse, I couldn’t figure out where the rage was coming from or how to rein it in. The anger became so inexplicable, tenacious and out of my control I finally checked in with a therapist. Diagnosis: depression.

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Depression doesn’t always look like depression

For plenty of people who become depressed, extreme sadness is a major symptom. But for other folks — like me — depression shows up in less obvious ways. That may be why, according to the Centers for Disease and Control and Prevention, only a third of people with severe depression seek treatment and only 20 percent of those with moderate depression get help.

“I think there are huge numbers of people who are depressed and don’t know it,” says Carol Landau, PhD, a clinical professor of psychiatry at Brown University. Just as I didn’t connect out-of-the-blue anger with major blues, they may have symptoms that they don’t recognize as depression. Here are five to look out for in either yourself or in your loved ones.

1. You’re mad at the world

Psychologists call this brand of depression “irritable” depression. You may catch yourself being impatient or overly critical of other people or of yourself, lashing out at loved ones or breaking down in tears. At the same time, adds Landau, the co-worker who always seems to be in a snit about something actually may be depressed and not an inherently nasty person.

Irritable depression is surprisingly common. A report in the Journal of Clinical Psychiatry found that of nearly 1500 depressed people, 40 percent reported feeling angry more than half the time. Some experts even believe that irritable depression should be a subcategory of major depressive disorder. And in fact, irritability is used as one criteria for diagnosing depression in kids.

Whether or not irritability becomes an official symptom of depression, Landau agrees it’s important to know it can be. “When you express depression through irritability, you alienate others, and detachment is the last thing you need,” she says.

2. You can’t get it out of your head

While it’s healthy and reasonable to try to solve a problem by thinking it through, a depressed person may take it to an extreme. He’ll fixate on something and worry about it excessively without doing anything about it. It's called rumination and is one of the least commonly recognized symptoms of depression, says Landau.

One aspect of rumination as a symptom of depression is sleep loss. A person who’s functioning well who wakes up in the middle of the night thinking about a problem mostly likely will be able say to himself, “It’s 3 a.m. I’ll deal with this tomorrow,” and go back to sleep, explains Landau. A depressed person will fret — and toss and turn — into the wee hours.

Rumination also can be a cause of depression and, as with irritability, lead to alienation. In one study, ruminators were more likely to ask for help than non-ruminators, but were less likely to get it when others grew tired of listening to them.

3. You self-medicate

Turning to comfort foods and overeating are classic signs of depression. Other forms of self-medication — drinking, popping pills — are not. Landau says moms of kids under age 5 are especially at risk of this particular manifestation of depression.

“Anecdotally this is especially common among young mothers who feel isolated or don’t get much help from their partner. By 4 a.m., the arsenic hour, they’re reaching for a glass of wine. One glass is okay; two or more are not,” says Landau.

Constant consumption of caffeine can be another sign. “Amphetamines used to be prescribed for depression,” she explains. “Someone who’s drinking tons of diet soda or coffee during the day may be going for the same effect.”

Related: Post-Partum Depression: Dads Get It, Too

4. Your body hurts

Because psychological depression and physical pain share the same biological pathways and neurotransmitters, depressed people are three times more likely to develop chronic pain than average.

According to a study in the Journal of the American Medical Association, this connection can make it harder to recognize depression for what it is: It found that 75 percent of primary care patients with depression complained only about physical discomfort, often leading doctors to miss their depression.

“Depression is often under-recognized and thus frequently undertreated,” the study authors wrote. “Providers frequently assess for physical causes of pain and treat medically instead of exploring the pain symptoms in a broader, biophysical context.”

Some experts believe pain associated with depression sometimes is really a symptom of chronic inflammation — the same immune-system-gone-awry condition that’s been linked to heart attack, Alzheimer’s disease and stroke. It’s a controversial concept, but in fact, adding anti-inflammatory medications to anti-depressants has helped some people with depression.

Related: Exercise Rx For Depression

5. You simply aren’t yourself

Anytime you find yourself doing something out of character — not showering or making your bed for days, say — or thinking, “This is really different for me — I’ve never let the laundry pile up like this before,” you may be dealing with depression. If you don’t feel particularly unhappy but these unusual behaviors persist, see your doctor. 

Even though there’s still a stigma surrounding depression, “it’s better than it used to be, with celebrities speaking out about their own experiences and more people seeking help from doctors,” says Landau. “General internists and gynecologists are better trained at spotting mental illness than they used to be,” she adds. Depression is treatable, but if it’s not treated, it gets worse.