Many people are pretty familiar with some of the tell-tale signs of depression — things like a persistent "low", "empty", or irritable mood, loss of interest in previously meaningful or enjoyable activities (an inability to deeply care about much), feeling worthless, being pessimistic, trouble sleeping or oversleeping, low energy, and of course suicidal feelings. Even people who are deeply familiar with depression, because they're healthcare providers themselves for instance, may take a long time to recognize the symptoms in themselves, however, or otherwise fail to seek treatment because their depression has convinced them that nothing will make things better.
Research additionally shows that people who later meet the diagnostic criteria for depression often see primary care providers many times without being diagnosed — as well as that once a diagnosis is made, patients aren't always given the tools they need to commence treatment, nor do they even know what the treatment options are in all cases.
Depression is literally "all in the mind" — but your doctor will still conduct a physical exam
The guidelines that help doctors diagnose depression specify that it's important for the doctor to ensure that the symptoms aren't caused by another condition, which includes conditions with a physical cause. It's for this reason that your doctor will want to conduct a thorough physical exam, including, in many cases, blood tests and urine tests, an MRI or CT scan, an electrocardiogram (ECG), or an EEG, a test that monitors brain activity.
Other medical conditions that can have symptoms that mimic those of depression include:
- Hypothyroidism or hyperthyroidism — a slow and fast thyroid can both induce symptoms that look a lot like depression, but are treated differently.
- A vitamin D deficiency.
- Cushing's syndrome, also called Cushing's disease, is caused by abnormally high cortisol levels over a prolonged periods of time.
- Stroke — some patients who have recently had a stroke will develop depressive symptoms as a result, and this warrants additional care.
- Heart disease.
- Fibromyalgia, a functional pain disorder in which you become much more sensitive to pain stimuli.
- Chronic fatigue syndrome, a disorder that, like depression, leads to persistent and extreme fatigue.
- Substance abuse.
How your doctor will screen for and diagnose depression: A psychological evaluation
The portion of the diagnostic process that specifically seeks to determine whether you have clinical depression will start off with an informative chat about your symptoms, their duration, your life, and how your mood is affecting your daily activities. If your doctor suspects you are clinically depressed, they will ask questions that will help them make the correct diagnosis.
Depression comes in a few possible forms, like postpartum depression (depression after childbirth), persistent depressive disorder (which lasts more than two years), and seasonal affective disorder (depressive symptoms during certain parts of the year, often winter). Your doctor will also screen for bipolar disorder, which is a different beast to depression but shares some common features.
Because your symptoms must have lasted at least two weeks to be diagnosed with depression, they'll ask how long you've been feeling the way you have.
You must also either:
- Suffer from a depressed mood on most days, for most of the day — this can show up as feeling low, sad, pessimistic, worthless, empty, hopeless, and also irritable. This observation can also made by people close to you.
- Or have lost interest in most daily activities, including those that previously really motivated you or gave you joy, again on most days and nearly all of the day. This may manifest as not caring or not feeling up to doing much, and again, others can also have made this observation.
Some people will meet both criteria, but you need to have at least one of these in order to receive a diagnosis of depression.
Other symptoms of depression your doctor will look at are:
- Spontaneous weight loss despite not dieting, because your appetite has decreased — or spontaneous weight gain because your depression is causing you to overeat.
- Insomnia — not being able to go to sleep or stay asleep — or hypersomnia, which means sleeping too much.
- Psychomotor retardation or agitation — this refers to either a physical slowing down (trouble doing things like showering, brushing your teeth, or going grocery shopping) or engaging in restless, "fidgety" movements that have no apparent purpose, like pacing, tapping, or a racing mind.
- Feeling fatigued or low on energy.
- Extreme feelings of guilt or worthlessness, disproportionate to your situation.
- Finding it hard to concentrate or make decisions.
- Persistent thoughts about dying, beyond a general fear of death, suicidal thoughts, suicide plans, or suicide attempts.
If you meet at least five of all of these diagnostic criteria, your ability to function has changed, the symptoms can't be explained by another medical condition — including other mood disorders — and you've been feeling this way for at least two weeks, depression can be diagnosed. Asking you exactly how severe your symptoms are is another part of the process, and your doctor will likely ask you to fill in a questionnaire to determine this yourself, based on the above diagnostic criteria.