Anti-psychotics, damn lies and statistics

Today, I was asked to clarify some information surrounding an earlier post about Carrie Fisher and the role that anti-psychotic medications may or may not have played in her death from a heart attack.  I appreciated the question which was about whether I’d seen the statistics put up by the Mad In America (MIA) blogger who wrote about Carrie Fisher (the blog which, incidentally, Dr Leaf had then uncritically decided to slyly try to regift it in the form of her newsletter article).

In the opening of her post, the MIA blogger said, “There’s an important question here. Is she one of the cases in point to explain why our community has a 25 year lower life expectancy?” and then threw in a table plucked out of context from a journal article.  At least, unlike Dr Leaf, the MIA blogger was intellectually honest enough to attach the source of the table, which was an article published in the European Heart Journal in 2012.

While the MIA blogger is certainly entitled to her opinion, I thought it was worth discussing the statistics in a bit more detail, if for nothing else than to give some context to the whole “anti-psychotics kill you” trope that keeps getting around.

First, there needs to be the proper context.  No one is denying that there’s a higher mortality rate amongst people with schizophrenia and other forms of psychosis, though I don’t see exactly where she got her “25 year lower life expectancy” line from. To me, that seems excessive.

Then to the study itself.  The paper that the table is extracted from is Honkola et al [1]. The study specifically examines the association between the use of different classes of psychiatric medications with the rate of sudden cardiac death during a coronary event (a heart attack, or angina).

In her post, the MIA blogger throws around a lot of numbers but she was loathe to put her numbers in the right context.  For example, she claimed that “smoking is four times safer than the older types of antipsychotics. And it’s twice as safe to smoke as it is to take any antipsychotic, including the newer ones”.  Except, her comparison is a fallacy of conflation – she’s comparing the all cause mortality of smoking (which is more like three-fold rather than two-fold, just FYI [2]) with the highly specific ‘sudden cardiac death during a heart attack’ mortality of the study she’s referencing.  It’s apples and oranges – the groups aren’t directly comparable.

Besides, even if her numbers were directly applicable, the positively immoral sounding four-fold increase in the rate of death sounds is just an association, not a cause.  There is a dictum in science, “Correlation is not the same as causation.”  Just because two things occur together does not mean that one causes the other.  There may be other explanations beside the medication that might explain that number, including but not limited to, statistical anomalies and lifestyle factors, and other factors not considered in the analysis.

There are other problems with relevance too.  Most of the numbers in the table were small and not statistically significant (that is, could have been related to chance alone).  The only strong numbers were for old anti-psychotics, phenothiazines, tricyclic antidepressants and butyrophenones, none of which are first line medications for psychosis or depression anymore.  Newer anti-depressants and the newer atypical anti-psychotics did not have a statistically significant association.

And, like I said before, this study is looking at the association between sudden cardiac death in people having a heart attack, which is a very specific form of mortality.  It’s not particularly applicable to everyone on the medications, so even if the 4- or 8-fold increase is rock solid, you can’t translate that statistic to everyone on anti-psychotic medications or anti-depressants, or Carrie Fisher for that matter since no one really knows how she died other than she had a heart attack.  The rest is just disrespectful speculation.

For me, rather than trying to take a table full of weak and inapplicable statistics and beat a conclusion out of them, a more useful thing would be to know the benefit or harm of anti-psychotics on all causes of death.  If anti-psychotics were really as poisonous as Dr Leaf and the MIA blogger portrayed, then all-cause mortality would be much higher in those exposed to the drugs versus those who were never exposed to the drug, which is why this study by Torniainen and colleagues [3] is particularly interesting, and in particular, this graph – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393693/figure/F1/

In this study, the chance of dying from any cause was significantly higher in those people with schizophrenia who were never treated with anti-psychotics compared to those who were treated.

Does this answer the question why there is a lower rate of mortality? Not really, because in fairness, this study also showed just an association between no anti-psychotics and a higher death rate.  It doesn’t specifically prove causation one way or another.

Does it show that we should throw anti-psychotics around like lollies, or that they are wonder drugs without any associated harm? No, they are medicines and need to be used responsibly.

It does show there’s a general benefit to anti-psychotics for people with schizophrenia so they’re not the toxic killers Dr Leaf and the MIA blogger try and make them out to be.

Anyone can cherry-pick weak statistics and bend them to suit their self-interested propaganda.  The remedy to damn lies and statistics is to look more broadly and consider the strength of the numbers and their context.  When we do that with the studies on anti-psychotic medications we see that they aren’t the evil killers that some people would like to make them out to be.

References
[1]        Honkola J, Hookana E, Malinen S, et al. Psychotropic medications and the risk of sudden cardiac death during an acute coronary event. Eur Heart J 2012 Mar;33(6):745-51
[2]        Jha P, Ramasundarahettige C, Landsman V, et al. 21st-century hazards of smoking and benefits of cessation in the United States. The New England journal of medicine 2013 Jan 24;368(4):341-50
[3]        Torniainen M, Mittendorfer-Rutz E, Tanskanen A, et al. Antipsychotic treatment and mortality in schizophrenia. Schizophrenia bulletin 2015 May;41(3):656-63

Advertisements

One thought on “Anti-psychotics, damn lies and statistics

  1. Pingback: Where are all the shepherds? | Dr C. Edward Pitt

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s