By the time I assessed the claimant, driving had become a source of considerable anxiety. Certain roads were avoided altogether. Sleep was disrupted. Concentration had deteriorated. The claimant described repeatedly replaying the collision in their mind despite recognising that, objectively, the incident appeared relatively minor. The legal representatives were asking a question that arises surprisingly often in Medico-legal practice: can a low-speed collision really cause post-traumatic stress disorder?
The short answer is yes. The longer answer is considerably more complicated.
One of the most persistent misconceptions in personal injury litigation is that the severity of a psychological injury can be measured by the severity of the physical impact. In practice, the relationship is far less predictable. Psychiatric injury is not determined solely by the amount of vehicle damage, the speed of impact, or the extent of physical injury. Those factors may be relevant, but they do not provide the entire answer. Human beings do not respond to traumatic events in identical ways.
I have assessed claimants involved in significant collisions who displayed remarkable psychological resilience. Equally, I have encountered individuals who developed persistent psychological symptoms following incidents that would generally be regarded as relatively minor. That should not be surprising. Clinical medicine has long recognised that trauma is experienced subjectively. What matters is not simply what happened but how the individual experienced what happened. Two people can be present at the same event and emerge with entirely different psychological outcomes.
This is where discussions about low-speed collisions sometimes become unhelpful. The debate often focuses on whether an accident was serious enough to justify psychiatric injury. That is not usually the correct question. The real question is whether the claimant meets the diagnostic criteria for a recognised psychiatric condition and whether that condition was caused by the incident in question.
The diagnosis comes first. The mechanism follows.
Post-traumatic stress disorder is a recognised psychiatric disorder with established diagnostic criteria. It is characterised by symptoms that may include intrusive memories, flashbacks, avoidance behaviours, hypervigilance, sleep disturbance, and psychological distress associated with reminders of the traumatic event. The diagnosis requires more than simple upset, worry, or transient anxiety following an accident.
Most people involved in a road traffic collision will experience some degree of emotional reaction. Many will feel shaken. Some may feel anxious for a period afterwards. Those reactions are normal and often resolve without formal treatment. PTSD is different. It involves a pattern of symptoms that persist and interfere with daily functioning.
The Medico-legal challenge arises because psychological symptoms exist on a spectrum. At one end are normal emotional responses to an unpleasant event. At the other are recognised psychiatric disorders that may significantly impair daily functioning. Determining where a claimant sits on that spectrum requires careful assessment rather than assumption.
In my experience, the greatest difficulties often arise when parties become overly focused on the mechanics of the collision itself. Photographs of vehicle damage are examined. Repair invoices are reviewed. Arguments develop regarding impact speed and accident reconstruction. While such evidence may assist in understanding the circumstances of the incident, it cannot determine psychiatric diagnosis.
A psychiatrist does not diagnose PTSD by looking at a damaged bumper.
The assessment remains clinical. The expert must evaluate the claimant’s symptoms, history, presentation, functional impairment, and the chronology of events. Alternative explanations must also be considered. Previous mental health difficulties, unrelated life stressors, pre-existing anxiety disorders, and other potential causes may all be relevant. This is often where the real Medico-legal work takes place.
The existence of psychological symptoms following a collision does not automatically establish causation. Equally, the relatively modest nature of a collision does not automatically exclude it. Each case turns on its own facts.
Medical records frequently play an important role. Contemporaneous GP notes may provide evidence of symptom onset. Treatment records may assist in establishing duration and severity. Employment records can sometimes help demonstrate changes in functioning after the incident. As with any causation assessment, the objective is to build a coherent picture using the available evidence rather than relying upon assumptions.
There is another reason why low-speed collision cases deserve careful consideration. The modern tendency to equate visible damage with injury can be misleading. Physical injuries may heal. Psychological symptoms can persist. I have seen claimants whose orthopaedic recovery was largely complete while anxiety, avoidance behaviour, and travel-related fears continued to affect their lives many months later. From a rehabilitation perspective, those psychological symptoms may ultimately become the more significant problem.
That does not mean every claimant reporting anxiety after a low-speed collision has PTSD. Far from it. The diagnosis remains relatively specific and requires proper psychiatric assessment. What it does mean is that low-speed collisions should not be dismissed as incapable of producing significant psychological consequences. The relationship between trauma and psychiatric injury has never been that simple.
After fifteen years in Medico-legal practice, I have become increasingly cautious about drawing conclusions based solely on the apparent severity of an accident. The collisions that look dramatic do not always produce the most significant psychological injuries. The collisions that appear minor do not always produce trivial outcomes. Medicine has a habit of reminding us that human responses rarely fit neatly into our assumptions. Psychological injury is no exception.
