Prozac and the Killer

By Neuroskeptic | May 2, 2010 12:55 pm

Uh-oh, here’s a troubling paper: Effects of selective serotonin reuptake inhibitors on motor neuron survival.

According to Anderson et al,

Motor neurons were challenged with fluoxetine and paroxetine at clinically relevant doses … In fluoxetine-treated motor neurons there was ~52% cell death while in paroxetine-treated cells there was 14% cell survival…. Both SSRIs decreased cell survival in a dose-dependent manner. This study is provocative enough to call for further in vivo studies.

Standard doses of fluoxetine (Prozac) and paroxetine (Paxil), two of the biggest-selling SSRI antidepressants, both had a devastating effect on the survival of mammalian nerve cells growing in a dish. Within just 24 hours, the antidepressants had caused over half the cells to expire, 85% of them in the case of Paxil. Take a look:

Oh dear. Should we be worried for the safety of the nerves of everyone taking SSRIs? I’m not, for two reasons.

Reason #1 is that one of the authors on this paper was a Dr Amy Bishop, aka the University of Alabama Shooter. Three months ago, Bishop shot dead 3 colleagues and injured 3 others during a departmental meeting at the University of Alabama in Huntsville.

A blog called Shepherd and Black Sheep did some nice investigating into Bishop’s work following the shootings. They pointed out that, of the five authors on the SSRI paper, one was Amy Bishop and the other four were her husband and three children. They’re all listed as working for a “Cherokee Lab Systems”, but

The website for Cherokee Labsystems — — has a notice “Please stand by. We are currently updating our site and will be on-line shortly” and also shows the web address defaults to

According to the Wayback Machine this web address — — was only active October 16, 2003 through January 30, 2005, but all the archived pages for that period show a website that relates to Cherokee Labrador dogs, not a genetic research laboratory.

Moreover, Googling with street view the claimed address for Cherokee Labsystems – 2103 McDowling Dr. SE, Huntsville, AL – shows a residential home…

Hmm. But, hang on, the fact that this research was done by a spree killer and her family operating from their garage, doesn’t mean it’s wrong. Maybe the research was why she did it: Was Dr. Bishop Mind-Controlled To Shoot Her Victims As Retaliation For Her Critical Research Paper On Prozac In 2009? Hey, I’m just asking questions.

Fortunately there’s a second reason to doubt that SSRIs cause this kind of motor neuron toxicity in people: SSRIs don’t cause this kind of motor neuron toxicity in people. If they did, everyone would collapse and/or die after popping a single Prozac.

That millions of people have been taking SSRIs for years and, whatever else may have happened to them, they are still standing, is proof they don’t. The fact that a low dose of alcohol (0.08% i.e. just “legally drunk” in terms of blood alcohol) also killed a large proportion of nerve cells in this study is more evidence that these results can’t be extrapolated to humans. Antidepressants are in fact commonly used to help treat the pain resulting from neuropathic nerve damage.

It’s always possible to explain away such differences. Maybe SSRIs can cause motor neurotoxicity in humans, but only at higher doses, or only after very long periods, or only in some people. Anything’s possible. But given that the effects actually seen in this study – dramatic, rapid, and present at normal doses – never happen in humans, such possibilities are no more likely, in the light of these results, than they were before.

This is the serious lesson of this paper: if you’ve got data showing that something causes some effect in animal models or cell cultures, but it doesn’t do that in real life, the simplest explanation is that there’s something wrong with your model, or your data. Unfortunately, Anderson et al is by no means the only example of putting the experimental cart before the clinical horse

ResearchBlogging.orgLily B Anderson, Phaedra B Anderson, Thea B Anderson, Amy Bishop, & James Anderson (2009). Effects of selective serotonin reuptake inhibitors on motor neuron survival International Journal of General Medicine, 2, 109-115

  • Pietr Hitzig

    I do not understand what Amy Bishop means when she states in the abstract that “further in vivo” studies are needed. I have read this brief, and poorly written article. The study is in vitro.

    I have noted that in vitro assessments of neuroprotection and apoptosis do not correlate with in vivo.

    As I am sure you know, 5-HT is an immunomodulator and promotes, in general,a Th2 bias. This is in contrast to dopamine which promotes Th1 and reins in Th2.

    The precursors of these monoamines, in combination, can be markedly effective treatment of various immune disorders.

  • Anonymous

    As a lover of your blog, why did you even highlight the writings of a serial killer (author) who has crony family members as co-authors? I mean, this was junk science from the get go and NOT worthy of your blog. Just my opinion.

  • Neuroskeptic

    Hey, you know my motto. No job too small, no paper too serial-killer-authored.

    But I think this paper is interesting because the claim is implausible even setting aside the author. And it's far from the only paper that makes such claims that don't accord with the clinical reality.

  • petrossa

    I can observe from personal experience that my motor coordination has degraded significantly over the last 20 years of taking an SSRI if i compare myself with my brother who didn't take any and is only 1 year older.

    Most notable fine motor skills are affected. I'm getting lately parkinson like trembling (checked for parkinson negative)

    So to me this seems a valid paper.

  • pj

    Perhaps the more obvious point to be taken from the paper is that neuronal cells are difficult to culture and pouring stuff into the culture medium is likely to screw it up.

    Presumably there's quite a large number of toxicity studies done in animals before licencing that looked at the histological effects of SSRIs and failed to find any motor neurone toxicity.

  • Bernard Carroll

    Neuroskeptic has it right: The model is not the disease. (Carroll's dictum)

  • NeuroPsych

    I assumed that this article was submitted for publication before she went GI Jane on her colleagues.

    Still hard to believe that it went to press.

  • Radagast

    People can be triggered to do all kinds of different things… Think of the way that phobics react to spiders, or snakes. If one was able to install a trigger, then one could also activate it. It revolts me to acknowledge the reality of this, but its a phenomenon that any hypnotist could confirm, and I don't doubt that there are people in this world who have researched it deeply, for their own ends.

    This is not to say that Amy Bishop was subject to such a thing, although it would be quite straight forward to identify the trigger and the person who installed it, if one accepted the possibility that it could be there.


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  • birth defects caused by prozac

    Maybe just a typo, Pietr?

  • Michelle Greg

    Well I guess that is free speech and what this our home stands for. A blog is just that. Love it or leave.

  • John_Stump

    You know shit about what your talking about.



No brain. No gain.

About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.


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