Mental Health

Antidepressant Users Less Likely to Have Long-Term Depression?

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As I mentioned last week, it’s very difficult to measure long-term outcomes of depression treatment due to the confounding depression variables like severity of depression, duration of depression, number of depressions and so on.

In short, the sicker you are, the more depressed you are, the more likely it is you’ll get treatment.

Antidepressant Treatment Outcomes Long-Term, A Study

I discussed the basic outcomes of this study: The association between antidepressant use and depression eight years later: A national cohort study by Colman et al. which tries to take these variables into account.

Colman et al. showed those who took antidepressants had better depression treatment outcomes than those who didn’t, eight years later, once confounding variables were taken into consideration.

I’ll now point out the strengths and weaknesses of this study as well as some other interesting tidbits shown or cited in the study. Oh, and I’ll give my opinion on what it all means.

Strengths of this Depression Treatment Outcome Study

No study, of course is perfect, but each has its strengths. In the case of this study on depression treatment outcomes, some of the strengths include:

  • An attempt to quantify and account for factors we know will affect treatment outcomes
  • Study uses a large, heterogeneous, real-life, population base
  • Quality, fairly comprehensive data available
  • Replicated findings of a British study involving anxiolytics (anti-anxiety medication) and antidepressants

Weaknesses of this Depression Treatment Outcomes Study

Weaknesses mostly bias the outcome towards the conservative. In other words, the relationship between antidepressant use and a positive long-term outcome may be stronger than reported.

  • Does not have 100% data over eight years (Those who dropped out had worse depressions. This biases the data likely indicating a stronger relationship than shown.)
  • Not a randomized controlled trial (not likely possible)
  • Does not capture comorbid (co-occurring) disorders (likely indicating a stronger relationship than shown)
  • Does not specifically capturing other treatments*
  • Didn’t control for perception of need for treatment. In other words, those who were able to identify the need for, and seek, treatment took antidepressants and had better outcomes. So a factor then would be the person’s treatment-seeking behavior.

For all the nitty gritty on the strengths and weaknesses of this depression treatment outcome study, see here.

Outcomes of Antidepressant Treatment of Depression, Facts

In addition to their main findings, here are some other interesting depression treatment outcome facts either shown or referenced in the study:

  • Antidepressants are particularly useful for those with severe symptoms
  • Of 285 depressed patients, those using higher levels of antidepressants were significantly more likely to recover from symptoms in the short term (from a 20-year study)
  • British study found that of 204 depressed patients, those using antidepressants or anxiolytics (anti-anxiety medication) were significantly less likely to be suffering from symptoms of depression ten years later
  • Maintenance use of antidepressants has been shown to reduce future depressions
  • Those with partial remission (still having some depression symptoms) are far more likely to experience future depressions
  • The longer depressive symptoms persist before treatment the worse the long-term prognosis
  • The most strongly correlated value to better outcome was recent antidepressant use

Funding of Depression Treatment Outcome Study

Because I knew you’d want to know (I did too):

Funding for this longitudinal depression treatment outcome study was provided by government, grant and award money. Study was cleared through the Health Research Ethics Board of the University of Alberta.

So Long-Term Antidepressant Use is Good?

Well, I can’t say that. What I can say is this study is suggestive^ of the fact that people who are depressed and take antidepressants do better over the long-term than those who don’t. But remember:

  1. People weren’t necessarily on antidepressants the whole eight years.
  2. The key (shown in studies and in my opinion) is to treat the depression as soon as possible and get all symptoms into remission.

So, that doesn’t mean get and stay on antidepressants forever, nor does it mean go on and off antidepressants. Those are individual choices depending on the person’s situation. If you can achieve #2 then your prognosis (in my opinion) is very good. And generally this is done with antidepressants, but depending on your personal situation, you may be able to achieve it through other means.

This also shows people taking antidepressants don’t do worse. This matters because there is a meme out there that taking antidepressants will somehow eat your brain and create mental illness.** This study suggests not.

A Little Bit More

* Study also talks about the role of therapy in depression treatment but no relationship was found between those who got therapy and those that had more positive outcome, suggesting there was no benefit to therapy. However, this is likely due to the broad definition of the word “therapy.” This is why I chose to omit information therapy findings.

^ This is not a causational relationship (where we know one thing causes another) as causation is hard to ascertain without real double-blind placebo controlled randomized study. And we don’t have that.

** Antidepressants actually increase the creation of neurons (neurogenesis) and increase brain volume.