Lack Of Sleep Can Compromise Confessions And Testimonies In Court

A recent study analyzed how sleep deprivation can affect testimonies and confessions used in legal proceedings. When a person goes many hours without sleep, areas of the brain responsible for memory, reasoning, and decision-making function worse. This can lead to inaccurate memories, greater vulnerability to false information, and impulsive decisions during interrogations. Researchers suggest that courts consider the fatigue level of people involved in investigations and propose limits based on the number of hours without sleep, since extreme deprivation can seriously compromise the reliability of statements.

We all know that lack of sleep leaves a person tired, irritable, and with difficulty concentrating. However, researchers are beginning to investigate an even more serious problem: Can sleep deprivation directly affect the quality of testimonies and confessions used in legal proceedings?

Despite seeming like an important factor, this topic has received little systematic attention in scientific research and legislation. A new study has compiled the available evidence to understand how extreme fatigue can influence how people remember, think, and make decisions during police investigations and trials.

To understand this problem, it's important to first know how the natural sleep-wake cycle works. The human body follows an internal biological rhythm, often called a "biological clock," which regulates when we feel sleepy and when we are alert. This system involves several regions of the brain and depends on chemical signals that control energy and attention levels.

When a person goes many hours without sleep, this balance is disrupted. As a result, the brain begins to function less efficiently, affecting attention, memory, judgment, and emotional control.

These changes in brain function are particularly concerning in situations like police interrogations or formal testimonies, where people need to remember details precisely and make careful decisions about what to say. Sleep deprivation especially affects the brain's so-called executive functions, a set of mental skills that allow for planning, evaluating consequences, and controlling impulses.

These functions depend heavily on the prefrontal cortex, a region of the brain responsible for reasoning and decision-making. When someone is very tired, this area of ​​the brain functions less effectively, causing the person to think less about future consequences and focus only on alleviating immediate discomfort, such as quickly ending an interrogation.

Another important problem is the impact of sleep deprivation on memory. Very tired people become more vulnerable to a phenomenon known as the misinformation effect. This happens when someone begins to incorporate false information into their own memories.

For example, during an interrogation, an investigator might mention a detail that didn't happen, and an exhausted person might end up believing that it's actually part of their memory. Over time, this incorrect information can seem as real as a true memory.

Researchers also point out that many people who come into contact with the criminal justice system already have sleep problems even before any interrogation. Situations such as trauma, violence, poverty, or chronic stress can cause prolonged sleep disturbances. This means that these people arrive at investigations already more vulnerable to the effects of mental fatigue. Thus, sleep deprivation can amplify pre-existing cognitive difficulties.

Analyzing previous studies, scientists identified three main effects of extreme fatigue on testimonies and confessions. First, memories can become less reliable, as the tired brain has difficulty accurately retrieving memories. Second, interrogations tend to last longer, since exhausted people take longer to process questions and formulate answers. Third, reasoning becomes less efficient, increasing the likelihood of hasty decisions, such as agreeing with accusations or making confessions to end the situation quickly.

To help courts and investigators better assess these risks, researchers have suggested a simple classification system based on the number of hours a person stays awake. After about twenty-four hours without sleep, mental functioning can already become similar to that of someone under the influence of alcohol.

After forty-eight hours, cognitive impairment is much more severe and can seriously affect judgment. After seventy-two hours without sleep, some people may begin to exhibit symptoms similar to a psychotic episode, such as extreme confusion or distorted perceptions of reality.

These findings suggest that sleep deprivation may represent an “invisible loophole” in the justice system. If testimonies and confessions are obtained when a person is extremely tired, the reliability of this information may be compromised. Therefore, the researchers argue that courts and investigators should consider the sleep status of people involved in interrogations and testimonies, documenting how many hours they have spent awake and developing policies that reduce the risk of judicial errors.

READ MORE:

How sleep disruption impacts the evidentiary value of statements and confessions: Toward evidence-based standards

Krizan Z, Curran B, and Leo RA

Psychology, Public Policy, and Law. 2026

DOI:10.1037/law0000487

Abstract:

Although sleep disruption carries implications for the evidentiary value of legal statements and confessions, there is only limited evidence and little systematic attention to this topic. In response, we reviewed existing research regarding the impact of sleep-related fatigue on psychological functioning in the context of investigative and legal processes, alongside its policy implications. First, we outline the sleep–wake mechanisms and the consequences of their disruption for psychological functioning. Second, we summarize the prevalence and severity of sleep disruption among populations interacting with the criminal justice system. Third, we review relevant U.S. law on the admissibility of statements under sleep deprivation, with a particular focus on confessions. Fourth, we tie the discussed processes and relevant evidence together to posit three dose-dependent consequences of sleep-related fatigue for the validity of statements provided by subjects involved in legal processes—(a) unreliable recollections, (b) increased duress, and (c) poor reasoning. Finally, we integrate these findings by considering how sleep disruption impacts the evidentiary basis of statements, while providing the first evidence-based guidelines on what level of sleep-related fatigue may be influential for statements in evidence. We conclude by suggesting practical steps to document its influence and advance the understanding of the impacts that sleep disruption has on legal processes. (PsycInfo Database Record (c) 2026 APA, all rights reserved)