Abstract: A commonly held view regarding terrorists and their actions is that, by and large, they do not exhibit any greater degree of mental health conditions than the general population. Yet, this has often been based on unchallenged evidence as to the presence of mental health conditions. This article uses data from Australian terrorism trials in the Islamic State era to examine the degree to which mental health issues exist among terrorism offenders and whether there is any causal link. The findings support the view that Islamist terrorists’ mental health is largely the same as the general population and finds that there is little evidence to support any causal link between mental health and terrorism.
As more individuals come before courts on charges relating to support for the Islamic State, additional reliable information has come to light about their backgrounds. A range of claims surrounding their actions have been tested during trial or agreed to as part of a plea deal, allowing terrorism researchers to rely on more accurate datasets to study certain aspects of attackers’ background.
This article uses data from Australian terrorism trials in the Islamic State era to examine the degree to which mental health conditions exist among terrorism offenders and whether there is any causal link between their condition and their offending. The article first outlines key previous scholarship on the mental health-terrorism nexus. Researchers have often had to rely on media reports, interviews with family members, or the offenders themselves to glean the presence of mental health issues; the challenges that this creates for reliability of the data are discussed in the second section of the article, with the author arguing that court proceedings and inquests by coroners provide more robust data than previous methods. The third section presents findings from such proceedings in Australia.
In the process of radicalization, mental health may be simply one of a number of causative factors. The link between mental illness and Islamist terrorism, however, is an issue that has attracted a degree of media and academic attention over the years even though there is actually quite limited research regarding the subject.1 There have been broader studies on the psychology of terrorism, including John Horgan’s book of the same name. Yet, this research has been much broader than the jihadi terror problem set in its treatment of terrorism and the aspects of psychology that it addresses. The best-known study into the motivation of jihadi terrorists prior to the emergence of the Islamic State was perhaps Marc Sageman’s 2004 Understanding Terror Networks, which examined 172 Islamist terrorists to gain an appreciation of their backgrounds, motivations, and means of organizing.
Rebutting the idea that terrorism could be explained by psychological factors, Sageman railed against the lack of empirical data regarding psychological research into terrorists. His analysis of psychological factors among the terrorist cohort was confined to a subset of 10 from his overall study group of 172. They were chosen because there was a greater degree of biographical information available for them, including court records. Sageman observed that there was an absence of any major mental disorders among his small sample of 10, thereby reinforcing the standing research view that there was no significant pattern of mental illness among terrorists.2 As a consequence, a conventional wisdom emerged that terrorism was “basically another form of politically motivated violence that is perpetrated by rational, lucid people who have valid motives.”3
After the emergence of the Islamic State, its concomitant attraction of Western Muslims, and increased focus on attacks against targets in the West, the desire to understand the motivation and background of an increasingly large problem spawned a range of more contemporary studies that sought to better understand the nexus between mental health and terrorism. The most recent work on this issue identified 25 studies, most of which occurred after 2013, that measured the rates of mental health problems amongst a range of violent extremists.4 The prevalence rates differed significantly between studies, reflecting the different definitions of mental health problems to be included, data collection methods and sample sizes.
Some of these post-2013 studies began to challenge the belief that Islamist terrorists were “rational, lucid” actors. A 2017 Dutch study, for example, used a comparison of police records of known or suspected jihadis with the medical records held by several healthcare providers—one of these providers estimated the proportion of jihadis with mental health issues to be approximately 60 percent (of whom a quarter suffered from severe mental health problems), well above the general global population’s rate of 25 percent.5 a While this figure is initially alarming, it also appears anomalous, as generally speaking most research to date appears to support the contention that terrorists are not more prone to mental illnesses than the general population.
In a study published in CTC Sentinel the same year, Emily Corner and Paul Gill examined 55 terrorist attacks involving 76 individuals where media reports indicated there was a link to the Islamic State. Using this data, they found that psychological instability was present in 27.6 percent of the individuals, comparable to the current worldwide average. These results were noted as being “extremely preliminary” given they relied on data sources from the lower end of reliability.6
Corner and Gill’s reference to source reliability is one of the reasons why it has been difficult for researchers to reach a coherent or consensus view of the link between mental illness and terrorism. There are a range of challenges in researching issues surrounding mental health and terrorism. The first issue is establishing a consistency of what is being measured. Some studies examined terrorist sub-categories, such as suicide bombers or lone-actors, to better understand whether mental disorders were more likely to account, in part or in whole, for their actions.7 Still others have sought to categorize the type of mental disorders that terrorists may have in order to understand if there is any correlation between the type of disorder a terrorist may suffer from and the terrorist action they undertake.8
There are also differences in the type of data that studies have relied upon and the qualifications of those reviewing it. Gaining access to individual medical records is a difficult proposition, as is gaining access to an individual interview subject. Then there is the level of training of the researchers themselves, their understanding of, or qualifications in, mental health. Because of these challenges, researchers have often had to rely on media reports, interviews with family members, or the individuals themselves in order to gather information. Such methods, however, are unlikely to reveal much by way of objective evidence given the dangers in accepting information gathered during interviews at face value. Where terrorists have been killed in the course of their attack, there are also a number of limiting factors that may contribute to over-diagnosing mental illness.9
The main challenge, though, is understanding exactly what is being measured. The use of the words ‘presence’ and ‘impact’ is particularly important when researching the issue of mental health and terrorism. Whether someone suffers from a disorder or a serious mental illness is something for psychiatrists and psychologists to determine, yet even here there can often be differing opinions between mental health professionals. A challenge for researchers is to determine the degree to which such diagnoses are, in fact, valid.
The same goes for the extent to which mental health issues and the terrorist act are linked. Correlation, for instance, does not equate to causation, yet many studies assume this to be the case because diagnoses or reports from open sources are often accepted at face value. Decision-making bodies such as courts offer perhaps the only opportunity where these diagnoses are contested and linkages between the condition and the terrorist action made. A criticism of research relying on court records is that officials such as judges and coroners are not themselves qualified in the area of mental health. Yet, their job is not to make a diagnosis; it is to make decisions based on the totality of the evidence presented. Because of this, their judgments should give a better indication of the true rate of mental health conditions among jihadis and the link between their condition and their actions.
This study seeks to provide data for both the presence and the influence of mental health conditions among Australia’s Islamic State jihadi cohort, and reflects the approach taken by the courts, which are interested in apportioning responsibility and imposing sentences that reflect the need for personal and general deterrence, and that also take into account the mental health history of the offender when relevant.
The Value of Court Data
The data used in this study has been sourced from court judgments and the findings of coronial inquests. Courts require that where there are claims of mental health issues made by offenders or their consulting psychologists or psychiatrists during trial or the post-trial sentencing process, those claims are examined and may be contested. In this study, there are some instances where the judge gave little weight to mental health claims made on behalf of the defendant, and in other cases, they were taken into consideration during sentencing. The same principle holds for coronial inquests where the coroner must take into account the mental health of the deceased and any impact it had on the action that he took.
It is this contestability and contextualization that sets court judgments and coronial inquests apart from other forms of data-gathering in this area. Researchers are able to obtain evidence regarding the mental health state of individuals based on the opinions of mental health professionals who may offer contrasting diagnoses that a court must apportion weight to. Given the potential pitfalls that exist in uncritically accepting statements given by individuals to mental health professionals when they may do so for personal benefit, as well as the fact that psychologists and clinicians may offer differing opinions regarding the same person, the role of the judiciary is critical in evaluating the validity of this type of data. This was reflected in one judge’s remarks during a bail hearing for a minor accused of a terrorism funding offense when he noted that there was “a need for caution in cases where examining psychologists act upon self-reporting.”10
The sentencing remarks of judges in a number of terrorism trials in Australia have also shown the inherent difficulties in relying on uncontested evaluations of an offender’s mental health to determine whether there is a connection between the offense and any mental illness. For example, in the case of Amin Mohamed who was stopped from trying to travel to Syria, the judge remarked that the mental health specialist’s assessment of Mohamed “was largely based on what you (Mohamed) told him and parts of that narrative are at odds with the jury’s verdict.”11 And in the trial of Hamdi al-Qudsi, the architect of one of the foreign fighter facilitation networks in Australia, the judge noted that al-Qudsi’s state of mind recorded in his treating psychologist’s report was “so much at odds with his life as established by other evidence that I cannot place any weight on it.”12
To date, the main problem with using judicial evidence in determining the connection between mental health issues and Islamist terrorism has been the paucity of records. As Corner and Gill pointed out in their 2017 study in this publication, most of the incidents they examined had not yet gone to court.13 Yet, as more individuals have come before courts charged with terrorism offenses and those trials have concluded, there is now a much richer body of evidence available to researchers to examine the link between mental health and Islamist terrorism offenses. The much larger numbers of potential research subjects as a consequence of the Islamic State’s ability to attract recruits from the West, however, must be tempered against the realization that many of those who traveled to Syria or Iraq were killed there. And unless they had a previous trial record, their data will never be captured.
Additionally, those killed while undertaking attacks in their home country will not always have mental health conditions that can be verified. Hassan Khalif Shire Ali, for example, who was killed after carrying out an attack in central Melbourne in November 2018 was alleged by his family to have had mental health issues; his general practitioner prepared a mental health treatment plan for him, but he never attended an appointment with a psychologist. The coroner later concluded that he was never formally diagnosed with any mental health condition.14 In the case of Man Haron Monis, who was killed by police in 2014 after taking hostages in the Lindt Café in central Sydney, an appraisal of his mental health was difficult because in the decade prior to his act, he had several healthcare providers, gave them incomplete and different histories, and did not tell them who else he had seen. The coroner in Monis’ case found that he was not suffering from a diagnosable psychiatric disorder at the time of his offense.15
Regardless of the significant numbers who died on the battlefield or the potential that domestic attackers may not have verified mental health conditions prior to their death, the fact remains that when legal proceedings eventually conclude for all those repatriated from Syria, the dataset relating to the mental health condition of contemporary terrorist offenders available to researchers will still be significant.
The Data from Australian Courts and Coroners
This article focuses on the Australian experience of those guilty of terrorism/terrorism-relatedb offenses in the Islamic State era.c The vast majority of these individuals had connections with the Islamic State, although there are a number who did not favor a particular group, or who supported al-Qa`ida-linked groups such as Jabhat al-Nusra. At the time of writing, 84 men and women have been charged in Australia with Islamist terrorism/terrorism-related offenses since 2013. Of these, 67 have pleaded or been found guilty and 17 still await trial and are therefore excluded from the dataset. In addition to those charged, two others were killed during their acts of terrorism, and their actions were subject to coronial inquiries that have concluded and the reports issued. This means that court or coronial proceedings have concludedd for 69 offenders, of which there is data regarding the presence and influence of mental health issues for 60 individuals from their legal processes regarding the presence and impact of mental health on their actions.
In cases of this nature, Australian courts normally draw on assessments from mental health professionals who have examined the offender. The judge will normally, but not always, refer to the offender’s mental health circumstances when handing down a sentence. Whether, and the degree to which, the evidence of the medical professionals is referred to in the written judgment is at the discretion of the judge. The reason that nine cases were not included in this study is because the sentencing document was not publicly available (three cases) or because there was not enough information in the publicly available sentencing document to determine whether mental health was considered a relevant factor or not (six cases).
Based on the trial outcomes and coronial findings regarding these 60 individuals, judges accepted mental health professionals’ reports that 15 individuals had mental health conditions. This represents 25 percent of the Australian sample group, which is nearly the same percentage arrived at in the 2017 CTC Sentinel study by Corner and Gill using broader data. Those conditions varied, with the most commonly mentioned being depressive or anxiety disorders, followed by substance abuse disorders. The figure arrived at in this study is a slightly higher proportion than the general Australian population who, according to the National Health Survey, reported a 20 percent rate of mental health disorders.16 e
The existence of a mental health disorder alone, however, reveals little about the nexus between mental health and the terrorism/terrorism-related offense for which the individual was found guilty. Defense arguments that a mental health condition was the substantive reason the offense was committed have proven to be quite rare. Out of the 60 cases examined, a defense of not guilty due to reasons of mental impairment was only put forward in two cases. Neither was successful.
The first of these was the case of Ihsas Khan, who was sentenced to 36 years in prison for a knife attack against an innocent passerby in Sydney’s western suburbs in September 2016. While the judge accepted that Khan suffered from a mental illness at the time of the attack (Crown and defense expert witnesses differed over whether it was schizophrenia or obsessive-compulsive disorder (OCD), he noted that “it was not, in any way, causally connected to his offending.”17 The other case involved Moudasser Taleb, who was found guilty by a jury of preparing to travel to Syria in 2017 to join the Islamic State. In Taleb’s case, there was a dispute between two psychiatrists over whether the offender was schizophrenic at the time of offending, and the judge noted the Crown and defense’s contestation of the testimony of the respective psychiatrists. This is yet another example of the difficulty in verifying the correctness of data when examining mental health issues in the terrorism field. The judge in this case noted that he both accepted and rejected parts of both psychiatrists’ reports, even though he also noted they were doing their best to assist the court.18
The jury found in the Crown’s favor and convicted Taleb. The judge remarked that while Taleb was mentally ill, he knew that what he was doing was illegal as evidenced by his furtiveness and his willingness to go along with a cover story suggested to him by an undercover police officer. Nevertheless, the judge placed great weight on the role that his mental illness played in reducing his moral culpability and sentenced him to a five-year good behavior bond. Taleb was subsequently placed under a Firearms Prohibition Order by the New South Wales (state) police. He was arrested in April 2021 for breaching that order when a loaded double-barreled, sawed-off shotgun was located in the bedroom of his home in Sydney.19
While in Taleb’s case the judge took into account his mental health conditions in imposing his sentence, it has not been a common course of action among Australian courts. In only five of the 60 cases was the impact of the mental health condition considered to have been relevant to the offense and therefore taken into consideration during sentencing, representing only 8.3 percent of those offenders. It is important to note that this does not necessarily mean that there was a causal link, only that their mental health condition could have reduced their moral culpability, made incarceration more onerous on the person, or could reduce the significance of deterrence on the individual.
The following are two cases where the judge did take into account the mental health of the offenders in sentencing. In the case of Alo-Bridget Namoa, who was convicted in 2018 along with her ‘Islamic law’ husband Sameh Bayda of ‘acts in preparation for a terrorist act,’ the judge considered that her history of mental health problems “materially contributed to her engagement with militant Islamic ideas and hence the commission of the offence,” making “it inappropriate to penalise her at a level which might otherwise have been called for by way of deterrent [sic] to others.”20 She was sentenced to three years and nine months for conspiring to undertake an act in preparation for a terrorist act. In sentencing another offender, Blake Pender, who was charged with one terrorism offense but whose actions were an extension of a long history of mental illness and violence, the judge was moved to note the need “to discriminate between individuals who would wish harm upon the Australian community and those whose words and actions are in all probability and to a significant extent the product of a disordered mind.”21 Pender was sentenced to four years behind bars and subsequently became the second person in Australia subject to a one-year continuing detention order, which meant that he remained in prison for a year after the expiration of his sentence.22
The issue of mental health and terrorism is a challenging research area because of the difficulty of establishing exactly what aspects should be measured and gathering sufficiently robust data in order to measure it. With a significant number of court proceedings related to Islamic State-linked terrorism now completed, researchers are today able to utilize court records as a means of data-gathering. Unlike other more subjective sources, offenders’ self-reported claims of mental health issues can be examined and if necessary contested by subject matter experts.
Using this approach, the Australian dataset has reinforced previous research findings that the incidence of mental health issues among Islamist terrorism offenders is similar to the population at large. In the case of Australia, 25 percent of jihadi terror offenders exhibited some form of mental health condition, as opposed to the national average of 20 percent. What the dataset has shown, though, is that the presence of a mental health issue is quite different from a causal link between mental health and acts of terrorism. In the case of the latter, while nobody was acquitted due to reasons of mental impairment, a link between mental health and terrorism, if only to reduce their moral culpability, was acknowledged by the court in just over eight percent of jihadi terrorism offenders. CTC
Rodger Shanahan is a non-resident fellow at the Lowy Institute in Sydney, Australia, where his research focus is on Islamism and Middle East security issues. He has been an expert witness in more than 30 terrorism cases in Australia and writes and lectures regularly on the issue. Twitter: @RodgerShanahan
© 2022 Rodger Shanahan
[a] It is unclear why the Dutch study came up with such a figure, although possible explanations may be because the sample included ‘suspected,’ as well as known jihadi radicals, as well as definitional issues given the scope of mental health issues considered was very broad and took into account psycho-social issues such as relationship and parental problems.
[b] Terrorism-related offenses in these Australian cases normally refer to criminal matters handled by counterterrorism authorities; these may include foreign incursion, ‘entry into proscribed area,’ or other related offenses.
[c] In all cases studied in which court proceedings were completed, the defendant either pleaded or was found guilty.
[d] This excludes appeals; however, to date, no appeal has successfully overturned a guilty verdict, nor have they substituted a different view of the nexus between mental health and the offense.
[e] This was based on self-reporting.
 Russ Scott and Rodger Shanahan, “Man Haron Monis and the Sydney Lindt Café Siege – Not a Terrorist Attack,” Psychiatry, Psychology and Law 25:6 (2018): p. 875.
 Marc Sageman, Understanding Terror Networks (Philadelphia: University of Pennsylvania Press, 2004), pp. 80-83.
 Paul Gill et al., “Systematic Review of mental health Problems and Violent Extremism,” Journal of Forensic Psychiatry & Psychology (2020), p. 6.
 See Paul Gill and Emily Corner, “There and Back Again: The Study of Mental Disorder and Terrorist Involvement,” American Psychologist 72:3 (2017): pp. 237-238; Paul Gill, John Hirgan, and Paige Decker, “Bombing Alone: Tracing the Motivations and Antecedent Behaviors of Lone-Actor Terrorists,” Journal of Forensic Sciences 59:2 (2014): pp. 425-435; and Jeanne de Roy van Zuljdewijn and Edwin Bakker, “Lone Actor Terrorism: Policy Paper 1,” International Centre for Counter-Terrorism, 2016.
 See, for example, Emily Corner, Paul Gill, and Oliver Mason, “Mental Health Disorders and the Terrorist: A Research Note Probing Selection Effects and Disorder Prevalence,” Studies in Conflict and Terrorism 39:6 (2016).
 Scott and Shanahan, p. 875.
 R v NK  NSWSC 498 (22 April 2016)].
 The Queen v Mohamed  VSC 581 (29 September 2016).
 R v Alqudsi  NSWSC 1227 (1 September 2016), para 113.
 “Findings of the inquests into the deaths of Sestilio Malaspina and Hassan Khalif Shire Ali,” Coroner’s Court of Victoria at Melbourne, June 28, 2021, p. 64.
 “Inquests into the deaths arising from the Lindt Café siege Findings and Recommendations,” State Coroner of New South Wales, May 2017, p. 72.
 “Mental Health Snapshot,” Australian Institute of Health and Welfare, Australian government, July 23, 2020.
 R v Khan (No 11)  NSWSC 594 (5 June 2019), para. 114.
 R v Taleb (No 5) (Sentence)  NSWSC 720 (14 June 2019), para. 65.
 “Aspiring ISIS fighter allegedly caught with loaded gun,” Daily Telegraph, April 17, 2021.
 R v Bayda; R v Namoa (No 8)  NSWSC 24 (31 January 2019), para. 117.
 R v Pender  NSWSC 1814 (18 December 2019), para. 64.
 Minister for Home Affairs v Pender  NSWSC 1644 (15 December 2021).