Psychiatric patients who receive physical restraints such as wrist straps are about twice as likely to experience a blood clot than those who receive sedating medications such as benzodiazepines, according to a study in the BMJ. While the study authors stressed that the absolute rates of blood clotting were low (about three to four cases per 1,000 patients), these findings support the need for deliberation when considering restraint with an agitated patient.
Why It’s Relevant
The physical restraint of psychiatric patients is controversial on ethical grounds, but this practice can also lead to adverse biological outcomes. Reduced mobility is an established risk factor for a blood clot—or venous thromboembolism (VTE)—for which individuals with psychiatric illness already face heightened risk due to lifestyle factors, medication side effects, and medical comorbidities.
By the Numbers
- Researchers examined Danish registry data from 24,423 adults who were physically or chemically restrained while admitted to a psychiatric hospital.
- One month after experiencing restraint, 0.35% of patients who were physically restrained developed VTE, compared with 0.17% of those given medications. In risk-analysis terms, for every 548 patients given a physical restraint instead of medication, one would develop VTE.
- In a second analysis examining only patients who experienced VTE during a hospital stay, the researchers found that the incidence of VTE was 4.5 times more frequent in the 14 days following physical restraint compared with stays with no physical restraint.
The Other Side
The researchers compared physical and chemical restraints, since both interventions are given for agitation. However, physical restraint is more common in people with severe aggression or acute psychosis, so the two patient groups likely weren’t identical. The researchers also didn’t have details on patients’ body weight or smoking status, two notable VTE risk factors.
Takeaway Message
“Given these potential harms and the continued uncertainty around VTE risk assessment and prevention in [psychiatric inpatients], it seems imperative to reduce the use of a key modifiable risk factor such as mechanical restraint,” according to the authors of an accompanying editorial. “While intended as a last resort safety measure, the benefits of restraint are difficult to weigh against its harms, because high-quality evidence demonstrating positive clinical outcomes is lacking.”
Related Information
“APA Resource Document Outlines Principles on Use of Seclusion, Restraint”
Source
Jakob Hansen Viuff, et al. Venous thromboembolism after mechanical restraint in psychiatric hospitals: population based cohort and self-controlled case series study. BMJ. Published July 1, 2026. doi:10.1136/bmj-2026-100016
