What is depression?
Every single person — including those who have never come anywhere close to meeting the diagnostic criteria for clinical depression — knows what it's like to "feel a little depressed". That is, a depressed mood means feeling sad, low, tearful, pessimistic, empty, lonely, and down.
A large number of different diagnoses actually fall under the umbrella of depressive disorders, and these diagnoses each have their own unique characteristics. What they have in common, though, is that those suffering from them will have a persistently low mood over a longer period of time. They'll lose interest in important activities, including those they used to enjoy, and their depressive symptoms will have a significant negative impact on their ability to function in daily life.
That, really, is the definition of clinical depression in a nutshell. The difference between being depressed and sad is that depression is a persistent problem, not merely a reaction to something sad happening in your environment that will pass as you process your feelings. Each individual diagnosis on the depressive spectrum has its own unique characteristics, however, and we'll take a look at what they are.
Major depressive disorder
Major depressive disorder is the depressive diagnosis that people are most likely to be talking about when they just mention "depression". It is one of the most common mental illnesses around, with at least 17.3 million people in the US alone having suffered one or more episodes — that's over seven percents of adults in the United States, and this estimate may even be on the conservative side.
If you approach your doctor because you think you have recognized the warning signs and symptoms of depression, they will look at whether you meet the diagnostic criteria for major depressive disorder. In the US, this will be done using the current edition of the diagnostic and statistical manual of mental disorders, the DSM-5. The DSM-5 does not recognize all possible physical symptoms of depression — research has shown that many depressed people suffer from joint pain, back pain, and gastrointestinal issues, for instance — but it covers most symptoms.
The symptoms of major depressive disorder listed in the DSM-5 are:
- A depressed mood.
- A loss of interest, or significantly reduced interest, in daily activities.
- Significant weight loss or weight gain, which can be associated with a loss of appetite or overeating as a result of depression.
- Suffering from insomnia or oversleeping on most days.
- Psychomotor agitation or retardation, which means a physical speeding up or slowing down respectively. This shouldn't just be a subjective feeling; others should be able to see it, too.
- Being fatigued and low on energy on most days.
- A negative self-image — inappropriate or excessive feelings of guilt or worthlessness. The "inappropriate" part means that these feelings are not proportionate to your situation.
- A reduced ability to make decisions and concentrate.
- Recurrent thoughts about death or suicide. This can include contemplating suicide or attempting it. Just fearing death is not considered part of this symptom.
So, out of all of these symptoms, you will:
- Need to have at least five, including either or both of the first two in bold.
- The symptoms should have been present for at least two weeks.
- The symptoms shouldn't be better explained by another condition or diagnosis.
Other types of depression and their characteristics
This is an overview article, not a book (that'd be the DSM-5 itself, which is rather long!), so we won't list all possible symptoms and other diagnostic criteria for other kinds of depression — but we'll take a brief look and include links to more detailed articles in case you'd like to explore these types of depression in more detail.
- Persistent depressive disorder (also called dysthymia or dysthymic depression) is a long-lasting form of mild to moderate depression that goes on for at least two years.
- Seasonal affective disorder (SAD) is a kind of depression that strikes seasonally, usually in cold, dark, winter months.
- Atypical depression, or major depressive disorder with atypical features, is a modifier for the diagnosis of major depressive disorder. People who have it often have increased rather than decreased appetite, oversleep rather than undersleep, temporarily feel better on receiving good news, and tend to have a fear of rejection.
- Psychotic depression is depression combined with psychotic features. These can include hallucinations (in which you can feel, smell, hear, or see stuff that isn't there) or delusions (in which you hold false beliefs despite ample evidence to the contrary).
- Premenstrual Dysphoric Disorder can best be described as the evil twin of PMS. It is a kind of depression that strikes around the time of a woman's period and that can be extremely debilitating.
- Situational depression is a layman's term to describe depression caused by an identifiable stressor — such as the death of a loved one, job loss, or the diagnosis of a serious health condition. The diagnostic term for this is adjustment disorder with depressed mood, and it can be diagnosed if you have some symptoms of major depressive disorder but not all, and are deemed to be reacting to your loss or stressor with an unusual severity.
- Postpartum depression — depression after you have a baby — is not actually a diagnosis on its own. Rather, the label would be major depressive disorder with peripartum onset, which means symptoms start during the last stages of pregnancy or within four weeks after the birth.
What causes depression?
Depression is a shockingly common but rather complex mental illness, and numerous factors likely work together to ultimately cause depression in a person. These factors include genetic, environmental, biological, and — of course — psychological ones. Hard-core research into the causes of depression, which probably vary from from one person to another, is still ongoing.
We do, however, know a lot about the risk factors — the things that make it more likely for a given person to become depressed. These include:
- A family history of depression.
- A personal history of depression — if you have been depressed before, you're more likely to become depressed again.
- Having experienced trauma.
- Being female — across all types of depression, women are more likely to become depressed or at least to be diagnosed with depression.
- Substance abuse.
- Other mental disorders often go together with depression. Anxiety and depression are a particularly common combo.
- Serious physical illnesses, especially those that cause chronic pain, increase your risk of depression. Being diagnosed with a life-changing or life-threatening condition, such as HIV, cancer, heart disease, or multiple sclerosis, also increases your risk of becoming depressed.
How is depression treated?
While you're in the thick of depression, it is common to feel like nothing can ever make you feel any better — but this is not true. No matter how severe your depression, there are treatment options for you. Accessing them begins with letting your doctor or a psychologist know that you think you are depressed. Once you are diagnosed, you and your healthcare provider can work together to figure out what the best treatment plan for you is.
Talk therapy — or psychotherapy — can, for many people with mild to moderate depression, be as effective as antidepressant treatment. Talk therapy can sometimes be used as a stand-alone treatment for that reason, though it is also often combined with antidepressants in cases of more severe depression.
Science-based therapy options for depression include:
- Cognitive behavioral therapy for depression has been shown to be extremely helpful for many people. It is a shorter program that helps you find new ways to look at your life and thoughts; extremely good for practically-minded folks.
- Interpersonal therapy for depression is also time-limited, and is especially likely to help you if you have interpersonal struggles — like dealing with grief, conflict with people close to you, or transitioning to a new role in life.
- Psychodynamic therapy for depression is more of a traditional approach that tends to last longer and delves deeply into past issues that may be contributing to depression now. It is especially suitable for people with childhood trauma. Shorter programs are available now, but this kind of therapy can take years.
Antidepressants, together with talk therapy, represent the first treatment option of choice. While they are unlikely to help more if you suffer from mild depression and are already attending talk therapy, people with moderate to severe depression can really benefit from antidepressants. At least one in five depressed people who wouldn't have been lifted out of depression without antidepressants will indeed feel better when starting an antidepressant — and research shows that you have about a 50 percent chance of responding well to the first antidepressant you're prescribed.
The classes of antidepressants include:
- Selective serotonin reuptake inhibitors (SSRIs).
- Selective serotonin noradrenaline reuptake inhibitors (SSNRIs).
- Tricyclic antidepressants (TCAs).
- Monoamine oxidase inhibitors (MAOIs).
Like any other medication, antidepressants can lead to side effects — around half of people taking any antidepressant will experience at least one side effect, though many people will notice that these side effects subside with time as they become used to the drug. Common side effects include nausea, headache, dysfunctional sleep, weight gain, and changes in libido or sexual function. When your doctor prescribes you an antidepressant, they should inform you of common and more serious side effects and tell you when it is time to seek medical attention for a side effect.
It is important to note that most antidepressants take a while to "kick in"; if you haven't noticed any symptom improvement on, say, the third day, this doesn't mean the antidepressant won't work for you. Be patient and keep taking your antidepressant exactly as prescribed. Never suddenly stop taking an antidepressant without your doctor's say-so, and never take more than the prescribed dose, either. If your antidepressant comes with dietary restrictions (MAOIs have them), stick to all instructions closely.
Other treatment options for depression
For more severe depression that has not responded to antidepressant therapy after your doctor has had you try several different kinds, other treatment options are also available. They include:
- Electroconvulsive therapy is, these days, a safe and effective therapy for treatment-resisant depression.
- Transcranial magnetic stimulation, which uses magnetic pulses that trigger electric activity in particular regions of the brain that are associated with depression, can also be effective and is less likely to lead to side effects.
- Deep brain stimulation involves the surgical implantation of electrodes into your brain. A pacemaker-like device in your chest then delivers electric currents. Used for movement disorders like Parkinson's for a long time now, deep brain stimulation seems to hold a lot of promise for people with treatment-resistant depression as well.
Alternative and lifestyle treatments for depression
Don't underestimate the potential power of lifestyle changes that can help treat depression, either. Including regular physical exercise in your life — especially in the outdoors, where you'll get some sun too — is especially likely to help improve your mood. Eating a healthier diet, rich in fruits, vegetables, whole grains, and low in added sugars and alcohol may help, too. Mild and even more severe depression may get better if you seek out social opportunities even when you don't really feel like it. This can include group therapy sessions where you can get support from people who are going through the same things. Finally, though depression can interfere with sleep, improved sleep hygiene may help you attain better sleep quality, and this can certainly help improve your mood.
Alternative treatments can also have a place in the treatment of depression, and ones with at least some science behind them include:
- Relaxation techniques such as progressive muscle relaxation, autogenic training, and guided imagery.
- Serotonin "supplements" — but be very careful and talk to your doctor before even considering buying any.
- St John's wort, which can in some people be as effective as pharmacological antidepressants but also has some of the same side effects — again, talk to your doctor before taking any.
- Nutritional supplements, such as omega-3 fatty acids and folate, if you are deficient.