Researchers at the University of Granada (UGR) have prepared a report for the General Directorate of Traffic (DGT) on the impact of mental health on road safety

The study also found that, when it comes to driving, some antidepressants cause effects similar to those of heavy alcohol consumption

A team of female scientists from the University of Granada (UGR), part of the Mind, Brain and Behavior Research Center (CIMCYC), has prepared the report “Psychophysical Conditions of Drivers with Mood Disorders and Anxiety” for the General Directorate of Traffic (DGT), a comprehensive review that analyzes the relationship between mental health, pharmacological treatments, and road safety.

The authors warn that although mental disorders affect approximately 34% of the Spanish population, only 0.63% of those renewing their driver’s licenses report having such a condition to the Driver Examination Centers (CRC), indicating that the problem may be underestimated.

The report notes that mental illnesses are associated with a higher risk of traffic accidents. Drivers with such disorders have a 72% higher relative risk of accidents compared to the general population without these conditions.

The analyses indicate that major depression can impair executive functions essential for driving, such as sustained attention, reaction time, and decision-making. In people with anxiety, problems with attentional control and reduced self-efficacy behind the wheel have been observed, while in bipolar disorder, impairments in attention and information processing persist, even during phases of clinical remission.

Furthermore, experiments using simulators and on-road tests suggest that people with partially remitted depression can regain driving abilities similar to those of healthy drivers, provided they maintain clinical stability and adequate psychosocial functioning.

One of the most relevant aspects is the analysis of the impact of certain psychotropic medications. The researchers emphasize that some antidepressants with sedative properties, as well as benzodiazepines and hypnotics, temporarily impair the psychomotor skills necessary for safe driving.

Among the detected effects are drowsiness, decreased alertness, psychomotor slowing, coordination problems, and an increase in erratic vehicle movements. The study notes that certain sedating antidepressants increase the vehicle’s lateral deviation—a measure known as Standard Deviation of Lateral Position (SDLP)—to levels comparable to those observed in drivers with high blood alcohol levels.

The review concludes that the combination of antidepressants and benzodiazepines exacerbates driving impairment and increases the risk of accidents, especially among young drivers and older adults. In contrast, non-sedating antidepressants do not appear to cause significant alterations in driving performance.

However, the authors note that pharmacological treatment should not automatically be interpreted as a contraindication for driving. The report emphasizes that fitness to drive must be assessed on a case-by-case basis, taking into account the patient’s overall clinical condition, their response to treatment, and specialized medical follow-up.

The study reviews Spanish regulations on psychophysical fitness for driving. The General Drivers’ Regulations stipulate that severe mood disorders are incompatible with driving, unless a favorable clinical report is provided, leading in certain cases to licenses with reduced validity and periodic reviews.

The researchers consider it necessary to strengthen assessment systems through standardized psychological screening tools, neuropsychological tests, and individualized functional evaluations, especially for professional drivers and older adults.

“The research advocates a multidisciplinary approach that combines prevention, mental health, and road safety, avoiding the stigmatization of people with psychological disorders and promoting awareness campaigns regarding the use of psychotropic medications and their potential effects,” explains Cándida Castro Ramírez, professor of psychology and one of the study’s authors.

As the CIMCYC researcher concludes, “road safety cannot be addressed exclusively through technical factors; it also requires consideration of emotional, cognitive, occupational, and psychosocial variables.”

The study was led by Cándida Castro Ramírez, along with David A. Salazar-Frías, Antonia P. Pacheco-Unguetti, and María Blasa Sánchez Barrera.

The research includes a systematic review registered in PROSPERO (CRD420251023655) and conducted in accordance with the international PRISMA guidelines. To this end, the team reviewed scientific publications indexed between 2015 and 2025 in databases such as Web of Science, Scopus, PubMed, PsycINFO, ProQuest, and Medline/CINAHL.

In total, 288 scientific studies were identified, of which 31 were ultimately included after applying methodological quality criteria and undergoing independent evaluation by specialized researchers.