For some people, long-term depression may not respond to treatment. This is called treatment-resistant depression.
There is no one reason for treatment-resistant depression.
Reasons why depression can sometimes be hard to treat include:
- Not staying on a medicine long enough. Antidepressants can take as long as four to eight weeks before they fully take effect. Unfortunately, many people - and sometimes even doctors - give up on a depression medicine too early, before it's had a chance to help.
- Skipping doses. If you don't take your antidepressant, it can't help you. You'll never really know if a depression medicine is working unless you take it exactly as prescribed.
- Unpleasant side effects. Many people who have side effects just stop taking their antidepressants. That isn't a good idea. Instead, talk to your doctor and get some help. You might be able to eliminate or ease the side effects and still get relief from your depression. Also, remember that side effects tend to decrease over time.
- Drug interactions. Some other medicines don't mix well with antidepressants. When taken at the same time, neither one may work normally. In some cases, interactions could even be dangerous.
- The wrong medicine or the wrong dose. Antidepressant drugs work very differently in different people. Unfortunately, there's no way to predict how well a depression medicine will work without trying it. So finding the right medicine, at the right dose, takes trial and error - and occasionally, some time. Many people give up before they find the right one.
- Your genes. Researchers have found a gene that they believe may make depression harder to treat in some people.
- Other medical conditions. Some medical conditions - like heart disease, cancer, or thyroid problems - can contribute to depression. Other conditions, like anorexia, can too. It's important that you treat any underlying medical problems in addition to your depression.
- Alcohol or drug abuse. Substance abuse often goes hand-in-hand with depression. It can trigger depression or make it worse. If you have a substance abuse problem, you need to get help.
- The wrong diagnosis. Some people are simply misdiagnosed with treatment-resistant depression. They might actually have another condition, like bipolar disorder or an anxiety disorder. This is why it's so important to work with an expert.
Treatment-resistant depression care and medications
If you have treatment-resistant depression, you have already typically not responded to two or more treatments, usually one or more antidepressants and/or psychotherapy. At that point, your doctor may suggest other options.
- Other antidepressants. If one type of antidepressant hasn't worked - or has caused unpleasant side effects - your doctor may suggest that you try another. This might be a new depression medicine in the same class of medicines or one in a different class. Again, you may need to stay on this medicine for up to eight weeks to achieve its full effects. You'll then need to stay on it for at least several months, depending on your doctor's recommendations. If this second one doesn't work, your doctor may try a combination of depression medicines. Your doctor may also recommend older medicines for depression, such as MAOIs or tricyclics.
- Augmentation with other medicines. If standard treatments aren't working, your doctor may add other medicines to your antidepressants. The combination can work in cases where antidepressants on their own did not. Types of medicines might include anti- anxiety medicines, anti-convulsants, anti-psychotics, lithium, thyroid hormones, and others. Your doctor may want to try a number of different medicines in different combinations. One drawback is that the more medications you take, the greater potential for side effects.
- ECT (electroconvulsive therapy). Although sometimes used as first-line treatment for people with severe, life-threatening depression, ECT is usually reserved for people with serious depression that can't be controlled with other treatments and the National Institute for Health and Care Excellence (NICE) advises it should not be used long term. It uses electric impulses to trigger controlled seizures in the brain. This treatment can rapidly relieve depression, although its effects often fade.
- VNS (vagus nerve stimulation). VNS is a new approach used in people with severe depression that hasn't responded to other treatments. Through a pacemaker-like device implanted in the body, VNS delivers regular electrical impulses to the vagus nerve, one of the nerves that relays information to and from the brain.
- Other experimental techniques. Researchers are working on experimental techniques to tackle treatment-resistant depression, like TMS (transcranial magnetic stimulation), MST (magnetic seizure therapy), and deep brain stimulation.