Is there something wrong with me?

That’s a primal question, and in the summer of 1993, it was my primal question. I was a young, ostensibly healthy man, but I felt weak as a kitten — tired and extremely run down.

Was I depressed?

I discounted the possibility because I couldn’t think of a good reason why I would be depressed. I was studying and writing a dissertation about American history, a subject that I loved. I had recently reconnected with my old high school sweetheart, and we’d decided to move in together and rekindle our romance. It didn’t add up — how could I be depressed when everything was going so well? So, I just decided I wasn’t depressed. I decided that these feelings were an odd funk that would soon pass.

It turned out they didn’t pass. Those feelings became a chronic depression that would take me years to heal.

One of the bedeviling things about depression is that when it visits a person, it doesn’t always clearly announce its presence. Unfortunately, there’s no bright line between the ordinary “blahs” and depression, a concerning clinical state.

That said, there are often cues or clues to help distinguish between the ordinary sad feelings that accompany life’s inevitable disappointments and the beginnings of a more sinister depression. Here are some of those cues, from my experiences as both a psychologist and someone who’s lived with depression.

1. Apathy

While depression can involve sad feelings, people with depression don’t actually feel sad in many cases. I know I didn’t, at least not at the beginning.

Rather than feeling sad, I simply felt lifeless. This feeling was one of being disconnected, dull, and apathetic. This kind of misery lacked the spark and caring of actual sadness. During the worst parts, if someone had come to the door to tell me that my dog had died, it’s possible that I might have just shrugged.

2. The absence of logic

Another potential distinction between sadness and depression is whether logical events can explain the feelings. Feeling sad because you broke up with your girlfriend, because you lost your job, or because your dog died — these reactions are expected and common.

I had sustained feelings of depression with no obvious reason for them. In fact, when I looked at my life objectively in 1993, it looked pretty good. I had money, people who loved me, and things I liked to do. When no events can explain sad feelings, or when the feelings seem exaggerated or out of scale to the events, these can be potential signs of depression.

3. Length of symptoms

Depression also lasts longer than ordinary sadness does. Feeling sad for a day or a week, with or without a reason, shouldn’t be cause for particular concern. Normal mood variation means that we have good days and bad days, even good weeks and bad weeks.

Sad, depressed feelings that go on for many weeks relatively uninterrupted are a cause for concern. Depression has an insistence and a persistence to it that ordinary sadness does not.

4. Intensity

Depression is often different in its intensity from ordinary sadness. Though ordinary sadness can be strong enough to move us to tears, depression has the potential to more fully take over the body and mind.

In 1993, I was frightened by my feelings. It felt somehow stronger than me and I had foreboding that if it kept on, I might somehow die. One of the scariest things about depression is that people are so consumed by it that they come to believe they even deserve these bad feelings — a belief that’s not typical of ordinary sadness.

In other words, you might consider the possibility that your feelings are more than sadness if you’re overwhelmed by them, or obsessed by the thought that you deserve them.

5. Difficulty functioning

Depression also involves a profound change in functioning. Usually when people are sad, they can still do their work, they can still relate to others, and they can still take care of life’s mundane tasks.

In states of depression, by contrast, people struggle to work. They often withdraw from friends and social events, and even struggle with what seem like simple tasks: getting out of bed, taking a shower, or buying groceries. These sorts of impairments are all warning signs that depression has taken up residence.

6. Complex symptoms

Depression is also more complex than sadness. Sadness is a feeling that we experience, often after a loss. Clinical depression, by contrast, is a syndrome that involves a range of concerning symptoms. Depression disturbs our sleep, it interferes with our ability to concentrate, and it’s associated with thoughts about death or suicide.

In 1993, one of the biggest clues that I wasn’t experiencing normal sadness is that I had completely lost my appetite for weeks on end, another classic symptom of depression.

7. Lack of desire

Depression involves a more serious break in our motivation than simple sadness. When people feel normal sadness, they can sometimes seek solace in a good movie, a good meal, or a nice conversation. When depression is taking root, the person is often too stuck, unable and unwilling to grasp these sorts of soothing activities.

This loss of desire for pleasure — whether for seeing a movie, delicious food, or the company of friends — is called anhedonia, and it’s another warning sign that depression may be afoot.

In sum, the more you notice these symptoms, the more likely it is that depression is at work and not simply an ordinary blue mood. If you think you might be depressed or if any of the signs above resonate with your experience, don’t hesitate to reach out for help. Depression is a serious medical condition and there are options available to help you manage it. Don’t suffer in silence.

For more information on how to identify and manage depression, reach out to your doctor or healthcare team.