A new study hints at a compelling connection between medication adherence and road safety. Individuals with schizophrenia who take their antipsychotic medications as prescribed are a lot less likely to get into a car accident.
A group of researchers from the University of British Columbia and other institutions found that drivers with schizophrenia who stuck to their antipsychotic treatment regimen were half as likely to crash compared to those who didn’t take their medication at all.
Appearing in the Canadian Medical Association Journal, this large-scale, population-based case–crossover study analyzed more than 1,100 police-attended crashes involving drivers with schizophrenia over a 15-year span. The findings could have major implications for clinicians, public health officials, and policymakers focused on traffic safety.
A Closer Look
Earlier studies have shown that drivers with schizophrenia face a crash risk about twice that of the average driver. But just how adherence to their medication might help mitigate that risk has remained relatively murky – until now.
The research team, led by John Staples, MD, relied on two decades worth of health and driving data from British Columbia to study 1,130 motor vehicle crashes involving more than 1,000 individuals with schizophrenia.
To qualify for the researchers’ consideration, each driver had to have filled at least one antipsychotic prescription in the 12 months leading up to the crash (as well as the year before a matched control period).
The team compared each driver’s medication use in the 30 days before the crash with their use in a 30-day period exactly one year earlier. This case-crossover study design helped control for individual traits like age, driving habits, or other stable characteristics, which let the researchers better isolate the effect of medication adherence on crash risk.
Striking Findings
Drivers had a mean medication possession ratio (MPR) of 0.69 before their crashes and 0.76 during the control periods.
The results were clear. Drivers who adhered strictly to their treatment regimen cut their crash risk in half compared to those who didn’t. This persisted across all subgroups and medical histories.
And the accidents these drivers got into weren’t trivial. Nearly half resulted in injury, and a little less than 1% of them were fatal. Additionally, police reports cited the driver’s physical or mental condition as a contributing factor in 44% of cases.
But perhaps most telling is that these drivers committed more traffic offenses in the months leading up to their crashes.
Medication Makes All the Difference
Antipsychotic medications can boost cognition, curb impulsivity, and mitigate the severity of symptoms. And all of that makes for a safer driver. While earlier research raised concerns that the typical side effects could make medicated drivers less safe, this study counters that forcefully.
Two older driving simulator studies also support the idea that treatment improves road performance. In one, untreated patients with schizophrenia had significantly worse braking times, but after treatment, their driving resembled that of the healthy control participants.
The new findings lend weight to the idea that the benefits of treatment – symptom control and better functional capacity, for example – easily outstrip any sedative side effects.
Real-World Implications
The study’s authors suggest that these results could guide medical advice and driving policy moving forward. It’s not unlike sleep apnea sufferers who must spend their nights with CPAP machines or epilepsy patients who must stay on top of their anti-seizure medications.
People with schizophrenia face a future with similar licensing conditions tied to their treatment compliance. And such controversial measures could certainly cut back on lower crash rates and safeguard public safety.
Of course, those public policy implications come shackled to serious ethical considerations. Tying driver’s license eligibility to medical adherence could come across as unreasonably coercive, especially for a group already living with the stigma of their condition.
Limitations … and the Road Ahead
As with any other study, this one is not without limitations:
- It only included incidents that included the presence of law enforcement, which left out an unknown number of less serious accidents.
- The study also lacked direct data on how much participants drove, what medications they were prescribed, and whether they actually took the pills they picked up.
As a result, the study’s authors insist that further research, especially an investigation that takes into account the varying safety profiles of certain antipsychotic drugs and how treatment programs could boost adherence without the stigma.
This study offers more than a new set of data points. It offers a potential shift in the narrative, challenging the notion that medicated drivers are just as dangerous as untreated schizophrenia patients.
As Staples and his colleagues point out, the next step isn’t just reaffirming these results, but how to integrate them into broader clinical, legal, and social contexts.
Further Reading
Can Cariprazine Offer a Less Sleepy Schizophrenia Treatment?
New Insights Into Xanomeline/Trospium
Children of Parents with Schizophrenia Face More Mental Health Issues
