By: Krista Kotsopoulos 

Introduction

Have you ever wondered about how daunting it might be to take the stand in a court of law? Now picture that thought with the added weight of dealing with a mental health disorder. The weight of a mental health disorder tends to affect those in various ways. Namely: struggling to cope, issues with alcohol and drugs, less motivation, paranoia/hallucinations, and certainly, several more (Mayo Clinic Staff, 2022). Unfortunately this takes a toll on people when it comes to fulfilling their duty while testifying during a legal procedure. Since developing a mental disorder is not a fault, the justice system should consider making aid consistently available and accessible to those who will be giving a form of testimony. The aim of this article is to demonstrate how post-traumatic stress disorder (PTSD), depression, obsessive compulsive disorder (OCD), and personality disorders, specifically borderline personality disorder (BPD), affect individuals which can impact the credibility of their testimony. Note that other mental health disorders such as acute stress disorder (ASD), schizophrenia, bipolar disorder, and numerous others can also impact the credibility of a testimony in a court of law. Furthermore, testimony credibility is shaped not only by the individual’s disorder but also by societal perceptions. In particular, a study done in the United Kingdom concluded that legal professionals “explained that their knowledge of mental health problems was either lacking, gained from media sources only, or based on intuition, which cannot be easily measured” (Reavy et al., 2016). This can also touch upon the credibility of  a testimony from a person with a mental health disorder, whether diagnosed or not, due to legal officials not fully comprehending what an individual is enduring. By shedding light on this topic of trauma on the stand, it demonstrates the need for a greater intersection between legal scholars and mental health professionals; to ensure a fair chance for those sharing their story while dealing with their own personal challenges.​​

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A Credible Witness 

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As seen in both pop-culture and real cases that have undergone litigation, a witness’ credibility is essential in weighing evidence to reach a verdict.. Different countries and legal systems might not fully concur with one another regarding what is considered a typical credible witness . This section of the article will focus mainly on what the Canadian courts deem as a credible witness, with a mention of how authors of Polish background shed light to what they concluded a credible witness was based on their findings. This upcoming discussion on what a credible witness is will help set the stage for the subsequent considerations regarding how a mental health disorder can influence how credible a testimony is. 

Paulson et al. (2023) discuss what is deemed a credible witness in a legal procedure under Canadian law.  Notably, they offer a criteria the trier of fact can utilize to determine if a witness is both credible and reliable. The authors first refer to R v. NS (2012) to emphasize that the judge or jury should carefully observe the attitude the witness is portraying as they give testimony. Following, they credit White v. The King (1947) to stress the importance of carefully noting the traits of the witness along with their intelligence skills and memory of the event they are being examined about. Thirdly, the scholars mention R v. RWB (1993) to demonstrate the importance of a consistent testimony both externally and internally and how these two factors can influence the final verdict. Subsequently, they offer an illustration for internal consistency as the testimony in question should be consistent with aligning details with previous statements. To demonstrate external consistency they offer the example of a witness delivering details that are similar to other testimonies; observing for coherence among statements. Afterwards, they credit the case R v. Laboucan (2010) for the notion that the trier of fact must consider the motive the witness may have, which could influence them to modify their testimony and how they portray it. With the stated criteria, the scholars allude to R v. WH (2013) to stress that the trier of fact has the responsibility to weigh the testimony they observe to carefully consider an array of facts throughout their deliberations. R v. Morrisey (1995) demonstrates how a truthful witness still might give untrustworthy testimony. To illustrate an example of how this could unfold in the real world: a victim-witness who has undergone PTSD due to a traumatic incident has the desire to tell the truth to obtain justice, though can have difficulty sharing their story due to challenges that arise from PTSD (Paulson et al. 2023).

Kabzińska and Dukała (2024) demonstrate how judges assess eyewitness credibility. The reliability of the testifier is non-trivial; as this includes the consistent stating of key details along with the potential personal motivation to give testimony, which could be intertwined from either a conflict or interest to the defendant. The scholars then allude to the fact that judges often focus on the individual testifying as their subjective motive when they do not deem them to be a credible witness. Though when they deem a testimony credible, they focus on the coherency of the content,  such as the delivered testimony corroborating with other evidence. This is especially considerable as the authors allege that judges may remain cautious even when they deem their testimony as credible. This could suggest that those delivering testimony have challenges along the way if the presiding judge is wary of their story. 

Based on these discussions from these credible authors, they demonstrate what specifically constitutes a credible witness. As both works mention the subjective traits of the witness such as motive and memory; this enhances a foundation of one’s knowledge to understand why these factors are important when considering credibility. 

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Impacts of Mental Health Disorders on an Individual 

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This section of the article is set to explain how PTSD, depression, OCD, and BPD impact an individual. The aim of addressing the impacts from such disorders is to demonstrate how undergoing life with a mental disorder can increase the challenges regarding a certain task, such as delivering testimony. 

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Post Traumatic Stress Disorder

The Diagnostic Statistical Manual of Mental Disorders, Fifth Edition explains the various catalysts that can trigger the onset of PTSD. A few being: experiencing the traumatic situation, being a witness to a traumatic incident, knowledge of a traumatic event of a loved one, and observing the details of the aftermath of a traumatic event. These experiences can, adversely, lead to symptoms such as negative recurring thoughts, flashbacks of the trauma, avoiding triggers of the event, disruption in emotions and thought processes, and difficulty to remember the traumatic incident in full detail (Center for Substance Abuse Treatment, 2014).  The symptoms alone can cause dysfunction in one’s life due to the dire side effects of PTSD. As previously stated, PTSD can fragment memory, causing one not being able to recall certain details regarding certain events (Sparr & Bremner, 2005). Within psychological literature, various scholars also report similar findings in regards to memory and PTSD. In particular, autobiographical memory has been linked to distortion as PTSD develops or persists (Ashbaugh et al., 2017). Similarly, another article refers to the adversities surrounding how PTSD can "especially [affect] memor[ies]” (Abdelaziz, 2025, p.4282).  The challenges regarding how being a victim of sexual assault can complicate PTSD and progression of memory, especially “[i]f  the perpetrator and victime share a connection…” then new memories along with old memories can trigger new troubles for the victim (Abdelaziz, 2025, p.4283). Unfortunately, these instances mentioned above, gives those suffering from PTSD an unfair disadvantage when trying to explain their story; as well as navigating their ordinary day to day life. 
 

​Depression 

Depression, or major depressive disorder (MDD), is defined according to the American Psychiatric Association, as a mental health disorder that affects perceptions, feelings and thoughts (Onyemaechi, 2024). Moreover, the Association lists symptoms that vary by severity and individual: loss of interest in activities, less energy, feelings of guilt, emptiness and/or hopelessness, and struggling to concentrate or remember things (Onyemaechi, 2024). Among research regarding depression and specifically memory, different scholars note how depression can disrupt different domains of the memory storing process. For instance, Sheline (2011) proposes a hypothesis for why those diagnosed with MDD have a decrease in volume in their hippocampus region. The neurotoxicity hypothesis offers the account that the hippocampus (partly responsible for memory) is sensitive to glucocorticoids, a stress hormone produced from the body’s adrenal glands (Chourpiliadis & Aeddula, 2023). This can consequently damage such brain regions if high levels of glucocorticoids are present, which is common in patients diagnosed with depression (Chourpiliadis & Aeddula, 2023; Sheline, 2011). To consider a new perspective, bidirectionalism, Dillon and Pizzagalli (2018) explain how the effects depression can have on memory; though they note that while also dealing with memory deficits can in turn aggravate depression. This is worth considering as even if a patient has been diagnosed with mild depression, it could become more aggressive if they have been previously struggling with memory distortion. Demonstrating memory and depression can reinforce each other, leaving individuals increasingly vulnerable.

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The Bridge between PTSD and Depression 

As noted above, PTSD and depression share similarities as they both impact one's ability to remember events. Though notably, there is not a massive gap within literature regarding how these distinct disorders can lead to comorbidity. A team of doctors explain in their objective that MDD can follow after one has been exposed to a traumatic event and developed PTSD. The doctors discussed in their results the comorbidity of both PTSD and MDD. They emphasized in their findings that 63% of patients diagnosed with PTSD still met criteria for PTSD, depression, or both 12 months later (O’Donnell et al., 2004). To relate these results back to memory, authors discussed how trauma and depression can impact one’s memory. In their findings, it was stressed that “the quality of trauma memories and depression are consistent with the idea that these memories are being processed in an overgeneralised, non-specific way” (Ashbaugh et al., 2017, p.113). In other words, this statement reflects the seriousness of how trauma and depression can cause individuals to forget key details of events. To further relate this back to memory, the neurotoxicity hypothesis also touches upon the comorbidity of these two disorders. Such hypotheses suggest that since there is a decrease in volume of the hippocampus, this can be a result of a combination and process of dealing with “depression [and] PTSD” or “chronic stress” (Sheline, 2011, p.1). This exemplifies how PTSD and MDD are intertwined since both can damage the hippocampus.  
 

PTSD and Depression’s Impact on Testimony

As noted earlier, PTSD, depression or their comorbidity, may impair memory. An unfortunate consequence of this is potentially impacting the credibility of one’s testimony; if one has memory difficulties while on the stand. As previous mentioned, Abdelazis (2025) explains how a victim-witness of sexual assault from a perpetrator whom they have had a relation with, can elicit new adversities to remembering the event in question. Adversely, this can make testifying significantly harder. For instance, if the defense attorney of the accused is asking pressing questions during cross examination, the victim-witness (who deals with PTSD, depression, or both), has an unfair disadvantage if they are not able to recall key details of the event in which they are being interrogated about. This, unfortunately, causes more challenges for the victim who is trying to seek justice. To allude to a real life example, Sparr and Bremner (2005) reference a trial that took place in the tribunal for war crimes, Prosecutor v Anto Furundzija (1998). Some brief facts about the case: approximately May 15, 1993, “Witness A [...] was arrested by members of the jokers”(p.73), and after being held hostage, she was sexually assaulted numerous times. The defence for Mr. Furundzija tried to use Witness A’s trauma against her by asserting that she did not have the capacity, due to her trauma, to remember correctly that the accused was not there when the sexual assaults occurred. Furthermore, the defence then brought in expert witness Elizabeth Loftus. Loftus opined that Witness A did in fact “[have] a continuous memory of her traumatic event”, (p.76) meaning that Witness A did not forget what had occurred to her during the assaults. Sparr and Bremner (2005) emphasize in their work that recalled memories may be altered as more time passes after  the incident. This can elicit levels of confusion while working with witnesses who have either PTSD or depression (or both), while delivering testimony. The example of the defence attorney trying to utilize a potential mental diagnosis, in order to win their case, reveals a greater issue within the justice system. Furthermore, this emphasizes the need for proper and credible diagnosis before an individual takes the stand. 
 

Obsessive Compulsive Disorder

The American Psychiatric Association defines obsessive compulsive disorder as recurring obsessions, which are not desirable. For one to cope with these obsessions, those diagnosed,  frequently perform an action in a repetitive manner, a so-called ritual. These rituals are disruptive and distressing, unlike ordinary habits.. Although, most experiencing such listed symptoms, understand that the thought processes which they are undergoing, are not wanted nor are they actually realistic (Phillips, 2024). Consequently, this disorder can also impact one’s memory. Zitterl et al. (2001) found that “OCD checkers show a deficit in a nonverbal memory but not in general memory…”(p.116). An example of this could be not remembering what kind of car was at the scene of a crime. Similarly, Muller and Roberts (2004) explain how there is existing evidence demonstrating the impairing effects OCD can have on one’s nonverbal memory. This occurrence happens, as non-verbal memory may be more challenging to store and therefore harder to recall. Another explanation, being that it is simply more challenging to obtain large numbers regarding verbal memory and in such cases studies have trouble by only observing bigger differences and not accounting for smaller ones. OCD can also damage autobiographical memories although this is usually a result of the comorbidity of OCD along with depression. 

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OCD’s Influence on a Credible Testimony

A part of testifying can be in regards to what the testifier saw, this can be more demanding for those who deal with OCD. As noted in the section regarding the symptoms of OCD, it was defined that those diagnosed can struggle to remember nonverbal events (Muller & Roberts, 2004). First, an illustration of how this could be problematic in court. To set the picture, visualize a man, diagnosed with OCD, looking outside on his front porch while dealing with what feels like an everlasting loop of obsessive thoughts; though shortly after he witnesses a drive-by shooting across the street. Regardless of the fact that the perpetrators were at the scene of the crime for approximately sixty seconds, he has trouble remembering the make and colour of the vehicle. This can decrease one’s levels of credibility on the stand as they would have difficulty recalling a key detail of the event in focus. To further relate this issue back to credibility, the trier of fact could deem the witness as unreliable which could then impede obtaining justice for the victim of the shooting.  This unjustly gives the witness a much more vulnerable position on the stand as the defence attorney representing the accused could utilize the witness’s diagnosis to their leverage. 
 

Personality disorder: Borderline Personality Disorder

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BPD is defined by the DSM-5 as a tendency to have unstable relationships, along with self-esteem troubles and struggling with impulsivity. Among these symptoms, the following can also occur: fearful of abandonment, impulsivity with alcohol and/or drugs, sex, eating excessively, and other self-harming tendencies such as suicidal thoughts and/or threats (Chapman et al., 2024). BPD can also make opening up about one’s past much more challenging. Watts (2024) highlights a case about a woman diagnosed with BPD. The main challenge to her diagnosis arose when she made efforts to heal by attending dialectical behaviour therapy. Though when she attempted to explain her traumatic past she was directed to “skills training”(p.78), which made her overwhelmed and humiliated because she had felt as if she had done something wrong by addressing her past. This can be very troublesome for those who seek help within the psychological field while battling with BPD, as counselors might stigmatize the patient.

BDP’s Touch on Testimony

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This section, in comparison to the previous ones, will discuss how the courts can weaken one’s credibility on the stand when a testifier has been diagnosed with BPD. Watts (2024) relates the notion of epistemic injustice to BPD. This connection between concepts will help set the stage in discussing how exactly courts diminish the credibility of those diagnosed with a personality disorder. Epistemic injustice, sheds light onto how people can be silenced by those questioning them, assuming they are not knowledgeable. This can also result in “testimonial quieting” which is explained as “dismissing a speaker’s capacity to provide worthy testimony” (p.78). Watts (2024) then bridges these ideas to emphasize how the credibility of one’s testimony can be vulnerable due to “self-censorship and premature dismissal” (p.78). This expands on how the courts unjustly deem those diagnosed with BPD as epistemically impaired, as some law officials do not perceive those diagnosed with personality disorders as worthy of credible knowledge. To further demonstrate this idea, Johnson and Elbogen (2013) spotlight how the legal system, as well as the medical field, views personality disorders as “not severe mental diseases” (p.209), not in need of resources or attention in research, and “not likely to change” (p.209). By this, one who takes the stand, while being diagnosed with BDP or another personality disorder has the chance of being stigmatized or being viewed differently and that their subjective mental state is not as worthy to be taken into consideration. These authors also underline that if one has a personality disorder along with another mental health condition then they have a higher chance of being questioned about such other psychological conditions they may have (Johnson & Elbogen, 2013). 

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Conclusion

​By addressing and analyzing the impacts mental health disorders can have on the credibility of one’s testimony, it is evident there should  be measures put into place to aid those battling mental health disorders while taking the stand. This issue should be addressed globally, as mental health struggles affect people worldwide. One strategy that courts around the globe could consider is the utilization of more psychiatric personnel being actively involved in the process of an individual testifying. This procedure could be akin to applying psychotherapeutic skills that consist of the psychologist aiding the testifier by priming memories that are hard to recall, as well as implementing aspects of cognitive behavioural therapy (CBT) to ease tensions around the traumatic or worrisome event in question (Nakao et al., 2021). Undoubtedly, legal systems will contest this strategy by offering the argument of monetary concerns. Though to refute this concern, one cannot determine the worth of justice being executed properly.  Imagine again being in the position of delivering a testimony while combating a mental health disorder. ​

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References

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