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The Drug Made Me Do It: An Examination of the Prozac Defense

The plot of a recent Hollywood thriller, Side Effects, revolves around many pressing legal and ethical questions surrounding the use of anti-depressant medications. The movie explores the life of a supposedly depressed woman—Emily Taylor—who seeks treatment from her psychiatrist. Emily’s doctor prescribes her an anti-depressant—Ablixa. Emily then proceeds to murder her husband in cold blood while under the influence of the drug. The movie seeks to explore the culpability of this depressed woman in a legal sense. During the trial, the psychiatrist argues that neither he nor Emily Taylor is responsible; rather, Emily Taylor was simply “a hopeless victim of circumstance and biology.” Is it possible that a drug could be responsible for one’s actions as argued by the psychiatrist in the movie? The answer is not clear. Nonetheless, the possibility that someone could escape criminal punishment due to a certain anti-depressant represents a serious ethical quandary that should be examined.

There is no doubt that certain substances have the capacity to markedly alter our motivations and inhibitions. For example, alcohol is a commonly referenced example. When one makes the choice to drink alcohol to get drunk, under most circumstances, one is likely to experience several of the side effects associated with alcohol consumption, such as difficulty walking, blurred vision, and impaired memory [1]. Additionally, drinking alcohol can also often lead to poor decisions of questionable legality. However, many people do not escape punishment because they were under the influence of alcohol because they choose to drink. When anti-depressant drugs come into play, the situation is much different because people are no longer voluntarily taking a drug.

These questions of legal responsibility have resurfaced with the increasing usage of anti-depressant drugs. In fact, the use of selective serotonin reuptake inhibitors (henceforth, SSRIs) has risen remarkably in the past ten years. According to a report released in 2011, the use of anti-depressants has increased 400% between 1988-1994 to 2005-2008 [2].

A visualization of anti-depressant use from a recent CDC report

Simultaneously, over the past 15 years, lawyers have increasingly attempted to use the so-called “Prozac defense” with differing degrees of success. The “Prozac defense” does not refer solely to the intake of Prozac; rather, the argument put forth by several prominent psychiatrists and lawyers relies on the notion that different SSRIs (such as Effexor, Cymbalta, Zoloft, Paxil, etc.) alter the mind and can cause one to make a decision that would not have been made if one were not to take the drug.

The history of the defense is fairly limited to the past decade. In fact, no overarching legal framework exists to deal with the potentially mind-altering side effects of SSRIs. Nonetheless, there have been several cases globally in which the court ruled that an SSRI caused an illegal behavior. Four of the cases are outlined here [3]. These decisions set an important precedent: a person can evade responsibility for an action due to the side effects of a particular drug. However, not every instance in which lawyers have employed a version of the “Prozac defense” has successfully extricated the criminal from punishment.

A summary of recent trial verdicts where an anti-depressant was involved

Specifically, the first major case that sought to deal with the legal ramifications of anti-depressant side effects involved a 60-year old man, Donald Schell (denoted as “DS 2001” in the above chart). In 1998, Schell was diagnosed with extreme anxiety and was prescribed Paxil to deal with his anxiousness. Within 48 hours of taking the drug, Donald killed his wife, daughter, granddaughter, and himself. One of Donald’s family members, Tobin, sued SmithKline (the Paxil manufacturer). Tobin’s lawyers argued that those who take Paxil have shown increased suicidal or homicidal thoughts. Predictably, SmithKline worked to deny these allegations by questioning the causality of such claims. However, expert reports used in the trial pointed to Paxil’s potential culpability in a small set of instances:

“[I]t is generally understood by most psychiatrists that a certain number of patients, perhaps five percent, will develop restlessness and anxiety when prescribed selective serotonin uptake inhibitor drugs (SSRIs)…Furthermore, a certain number of depressed patients are known to “switch” in to hypomanic states when treated with antidepressant drugs. When a patient has a hypomanic history (Mr. Schell appears to have had none) or already exhibits akathisic symptoms (Mr. Schell did), SSRI compounds should not be prescribed …[4].”

Tobin’s defense was ultimately successful, marking the first verdict against a pharmaceutical company in the United States. This case set an important precedent that a drug can in fact be responsible for the unlawful actions someone may take when under the influence of anti-depressants.

As many may suspect, proving a drug caused an action can be quite a feat. First, one must demonstrate that a specific drug can cause some individuals to commit murder and/or suicide, for example. Second, the drug must be the cause of someone’s specific actions in a certain case. Third, as in the Tobin case, the lawyer must prove beyond a reasonable doubt that the pharmaceutical company was also aware that a particular drug could cause an individual to commit homicide if certain previous symptoms existed.

The first criterion has some scientific backing. Many studies have shown that certain SSRIs could have adverse effects on certain subsets of the population that have certain pre-existing symptoms or genes [5]. However, the small nature of this group of people makes it difficult to establish an overarching legal framework that deals with all cases that may have involved the intake of an anti-depressant.

The second criterion poses not only a problem in the case of criminal culpability in SSRI product liability cases but also other criminal court cases. The nature of statistical inference requires that researchers look at overall trends in behavior. It is then difficult to predict accurately how one individual will behave with exact precision. Moreover, even if a lawyer can point to research that suggests anti-depressants can cause impulse inhibition, aggression, and homicidal thoughts in individuals, one cannot attribute such findings to the actions of an individual case with exact accuracy. Combating this issue embodies a huge statistical challenge for psychiatrists and lawyers alike.

Lastly, the assumption behind the anti-depressant defense is that someone has awareness of the potential consequences of the drug and is therefore responsible for the actions taken while on the drug. This can pose a daunting legal challenge for a multitude of reasons. For example, if pharmaceutical companies put warning labels on their drugs, then who is responsible if someone takes an SSRI and commits suicide? Additionally, our medical system, as it stands, assumes that a psychiatrist possesses professional knowledge and expertise of when and to whom to administer SSRIs. Therefore, if a medical doctor prescribes a particular drug to a patient knowing the drug’s side effects, often a pharmaceutical company would argue they are no longer responsible for the patient’s actions while under the influence of a drug. The question of responsibility has no universally clear answer, which is what makes attributing legal accountability in the case of criminal acts incredibly difficult.

Ultimately, I believe that pinning responsibility on one sole actor may not be feasible because the issues of legal culpability remain incredibly complex and intertwined. Given that many can and do benefit from taking Prozac, Zoloft, and other similar drugs, pharmaceutical companies should not stop producing SSRIs given depression’s prevalence [6]. It would also not be wise to place responsibility exclusively on the clinician in fear that doing so may discourage psychiatrists from prescribing anti-depressants when it is appropriate. Where does that leave lawyers and clinicians?

In my opinion, lawyers have an obligation to learn about how neuroscience could inform the legal system, for better or for worse. Given the increasing prevalence of legal cases that have drawn on neuroscientific evidence (like the Schell case mentioned above), it is clear that fluency in neuroscience will be necessary in order to grapple with complex questions revolving around sentencing. For example, in a Canadian homicide case, the Winnipeg court called on expert psychiatric testimony to determine whether Prozac played a role in a murder case. In 2011, the judge did in fact conclude that the 16-year old Canadian teenager would be tried as a minor despite the prosecution’s push to charge him as an adult [7]. As this case and the Schell case demonstrate, neuroscience, psychology, and law will inevitably encounter one another in the court of law in the coming years. It is ultimately my hope that the individuals working in these fields can work synergistically in order to craft a legal framework that appropriately deals with individuals that have a history of mental illness in terms of fair sentencing and punishment.

Want to cite this post?

Marshall, J. (2013). The Drug Made Me Do It: An Examination of the Prozac Defense. The Neuroethics Blog. Retrieved on
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[1] National Institute on Alcohol Abuse and Alcoholism. (2004). “Alcohol’s Damaging Effects on the Brain,” Alcohol Alert, 63. Retrieved from

[2] Wehrwein, Peter. (2011). “Astounding Increase in Antidepressant use by Americans,” Harvard Health Blog. Retrieved from

[3] Healy, David; Herxheimer, Andrew; and Menkes, David, (2006). “Antidepressants and Violence: Problems at the Interface of Medicine and Law,” PLoS Med 3(9). Retrieved from

[4] Whitehead, Paul (2003). “Causality and Collateral Estoppel: Process and Content of Recent SSRI Litigation,” Journal of American Psychiatry Law 31. Retrieved from

[5] Lucire, Yolande and Crotty, Christopher (2011). “Antidepressant-induced akathisia-related homicides associated with diminishing mutations in metabolizing genes of the CYP450 family,” Pharmacogenomics and Personalized Medicine 4. Retrieved from,%20Dr%20Yolande%20Lucire,%20Part%204,%20Sept%2030%20Sept%202011.pdf

[6] Gibbons, Robert; Hur, Kwan; Brown, Hendricks; Davis, John; and Mann, John (2012). “Benefits From AntidepressantsSynthesis of 6-Week Patient-Level Outcomes From Double-blind Placebo-Controlled Randomized Trials of Fluoxetine and Venlafaxine,” Arch Gen Psychiatry 69(6). Retrieved from

[7] McIntrye, Mike (2011). “Judge Agrees Prozac Made Teen a Killer,” Winnipeg Free Press. Retrieved from


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