When I was diagnosed with major depression at 22, I was too deep within the fog of the illness to much care that finally, after years of struggling, I had an answer as to why I felt so impenetrably bad, and that with treatment, I could improve.

Later, once I began therapy and started taking antidepressants, I began to feel better, which resulted both in relief and a strange sort of guilt. I was grateful to be improving, surely, but remorseful that for years I didn’t seek medical help and that I had discounted even severe symptoms as the natural effects of just being in a rut, or of being stressed out.

That I waited so long to take action is not unusual, and my delay was likely a result of both misinformation and lack of information altogether.

“According to recent studies, about 1 in 5 Americans meet criteria for a diagnosis of major depressive disorder,” says Erlanger A. Turner, Ph.D., clinical psychologist and assistant professor of psychology at the University of Houston-Downtown. “However, many people don’t seek help either due to stigma or lack of information about treatment.”

To help, mental experts explain the symptoms of depression to help you determine if you or a loved one may need to be assessed for a depressive disorder.

A sadness that doesn’t have a specific cause and hinders function

“Everyone has sad moods, and most of us know what we do when those moods hit: call a friend, watch a sad movie and cry, eat some comfort food. However, what many people do not know is how to tell if you are moving from being sad to being in a clinical depression,” says Dr. Dara Gasior, PsyD, director of assessment and training at High Focus Centers, an outpatient addiction rehab and mental health services provider.

“The biggest sign that I look for is how much your mood is impacting on your level of functioning,” Gasior adds. “When you are feeling sad, you usually are able to complete the daily tasks of your life, you just feel badly while doing so. When you enter into a state of depression, the sadness starts to interfere with your level of functioning.”

It lasts longer than two weeks

Dr. David Hu, a psychiatrist and the medical director at Behavioral Health of the Palm Beaches, notes that not only does depression differ from sadness in terms of severity, it also differs in duration.

“People who suffer from depression typically have a low mood that lasts most of the day on most days, for more than a couple weeks,” Hu notes.

Your thoughts are black-and-white and pervasive

During these weeks your mind is likely occupied by what Kita S. Curry, Ph.D, CEO of Didi Hirsch Mental Health Services (and someone who suffers from depression) describes as “persistent thoughts of failure, hopelessness or shame, and [you’re] thinking in black-and-white.”

Types of thoughts you may experience, according to Curry: “‘No one has ever loved me; it’s always been this way; it will never get better!’ That’s when you know you’re probably depressed.”

This sense of hopelessness can be so pervasive you may find yourself unable to feel joy, even when great things happen.

“At one point, I knew I was feeling blue, but when I wasn’t excited that I was a finalist in a book contest, I realized I was depressed,” says Curry.

Improving your perspective feels impossible

“Depression does not allow for conversation around change,” says Laura Federico, a licensed clinical psychologist. “It can feel nearly impossible to shift thought patterns, improve motivation, or create a new perspective when coping with depression.”

Federico adds that these feelings are unlike sadness, which though “painful, disruptive, and difficult, [are] ultimately consistent with our sense of self, and manageable.”

Disturbances in sleep (pro tip: you can track these)

Sleep disturbances are a near guarantee with depression — and they can run the gamut from sleeping too much, too little or in unusual patterns.

“Many clients I see struggle with insomnia. Either they can't fall asleep at night or have trouble staying asleep. We know that many people with depression also struggle with anxiety, which impacts quality of sleep as well, and the symptom of insomnia crosses over between the two,” says Rachel Dubrow, a therapist who specializes in treating anxiety and depression.

“One of the best ways to do this is through a sleep journal or using a smart device, such as a tracker, phone, or watch, where it either automatically records the quality of your sleep and how many times you wake up,” says Dubrow. “To do this with a journal, write the date, rate the quality of sleep from 0 (didn't sleep) to 10 (slept through the night restfully) and then write out when you woke up and when you fell back asleep.”

Changes in appetite and/or weight

“Another symptom of depression is gaining or losing weight with or without a known reason,” says Dubrow. “Some clients I see gain weight because they are ‘emotional eaters’, and others don't seem to have an appetite at all and end up losing weight. This is very different from intentionally restricting or overeating.”

“I recommend a medical workup first to rule out any other reasons for these symptoms,” Dubrow says, adding that you should also keep a food diary or food log to track appetite.

“One way is to use a food tracking app where you can scan or type in the names of the foods or input a recipe to track overall calorie count,” she says. “Another way is to keep a journal on paper or on a phone/tablet where you list the date, rate your appetite before eating, and then list out the food and drink consumed.”

Depression runs on a spectrum and you may be able to ‘seem’ normal

Depression runs on a spectrum, meaning you may experience all of these symptoms, or only some of them, with varying severity.

“It can be hard to identify consistent symptoms of depression because each person is different and the criteria for diagnosis is so broad,” says Turner.

You may actually be able to still function despite having depression — but you’ll likely feel that you’re putting in extra effort just to pass as OK.

“Sometimes, when it comes to the more high-functioning amongst us, we seem to be able to pull it together and life looks okay on the outside,” says Dr. Perpetua Neo, a clinical psychologist . “For [others] you can't work, socialize or fulfill your personal/relational obligations. Even say, opening the curtains to let in light is an effort.”

What if you’re grieving?

Disruptive sadness is normal after a significant loss such as the death of a loved one — but even this important human experience can morph into something more serious.

“Grieving is a non-linear path, and both individual and cultural factors need to be assessed carefully when differentiating grief from depression,” says Mark D’Agostino, MD, assistant medical director at Silver Hill Hospital, a non-profit psychiatric hospital. “When feelings of grief become more pervasive and complex, resulting in isolation, appetite and weight changes, an inability to perform daily functions and thoughts of suicide, it is important to seek a professional evaluation.”

Samuel Ball, Ph.D., director of psychology & executive programs at Silver Hill Hospital adds that when deep grief extends well beyond two months, and is accompanied by any other symptoms, you should consider evaluation for clinical (major) depression.

Check off any of these? Here’s how to find care and what to expect.

If you or a loved one is exhibiting any of these symptoms, talking with a mental health expert the next (and most crucial) step.

“One of the quickest ways to find a mental health provider is by visiting the state psychological association’s website,” says Turner. “Most psychological associations offer a directory to look for services. If you’re in a crisis, you can always visit the emergency room and they will provide immediate care and possible referral sources. If you have time to do extensive research, searching the internet for reputable providers is helpful. The American Psychological Association and SAMHSA offer treatment locators. Once you are able to seek out services, they can evaluate you for the appropriate diagnosis.”

A total round-up of symptoms

The symptoms explored here just some of the core attributes of depression. The experts consulted here also highlight other effects including loss of interest, trouble concentrating/making decisions, unexplained aches and pains and social isolation.

DepressionHurts has a great checklist of all the symptoms you may experience when depressed and offer a way to gauge intensity.

But really, if you have any reason to believe you may be depressed, please don’t put off getting help like I did — my delay didn’t change my diagnosis, it only extended the suffering.

If money is a concern, or if you don’t have healthcare, check out our guide on how to find care on a budget. And remember, depression is, as Dubrow notes “very treatable.” A diagnosis isn’t the end of the road; it’s the beginning of getting back on track.

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