In August 2013, the NFL settled a lawsuit brought against it by former players who alleged that playing football led to Alzheimer’s disease and other neurological disorders. The media and some researchers have claimed that the disorders result from a syndrome called chronic traumatic encephalopathy (CTE)—a brain disorder caused by repeated concussions and head trauma that occur in sports.

Despite the settlement, Loyola neuropsychologist Christopher Randolph, PhD, doesn’t believe that CTE exists.

In his latest study, Randolph, a professor at the Stritch School of Medicine and the former team neuropsychologist for the Chicago Bears, screened hundreds of former NFL players for cognitive disorders. About 35 percent, a notable amount, reported subjective concerns about cognitive impairment. Randolph conducted further testing of 41 of the players who did show cognitive impairment, and compared them to a control group of non-athletes with similar complaints. He found no significant difference in the patterns of cognitive deficits between the two groups, both of which met criteria for a diagnosis of mild cognitive impairment (MCI).

Some proponents of CTE, according to Randolph, characterize it as a neurodegenerative disease, leading to, among other things, a high likelihood of suicide. But, in fact, he says, “The all-cause mortality rates of NFL retirees are only half those of men their age in the general population, and the suicide rates of NFL retirees are even lower. Retired NFL players as a group appear to be physically and mentally healthier than the general population of men their age.”

Randolph recently participated in a public debate with Robert Stern, PhD, of Boston College, a leading proponent of the theory that sports concussions cause CTE. Stern argued that the accumulation in the brain of a protein called tau, which has been found in the brains of former football players who committed suicide, indicated CTE. But, according to Randolph, that same amount of tau can be found in the brains of healthy people as well.

“There are no epidemiological data to suggest the existence of CTE ,” he says. “There are no data to suggest that there are any long-lasting or permanent results of concussions, no matter how many you get, let alone a distinct syndrome.”

The bottom line, according to Randolph, is that the disorders that affect former football players fall within clinically established forms of psychiatric and neurodegenerative diseases, and that current evidence doesn’t support the definition of a new syndrome. Randolph prefers to err on the side of caution, he says, because diagnosis can affect action.

“The proponents of CTE strike me as being unjustifiably alarmist,” he says. “There are consequences to the propagation of a belief that every psychological or neurological symptom experienced by a retired football player may be the manifestation of CTE, when we don’t even know if such a disease exists. Imagine you are a retired NFL player who develops a major depression. How might your actions differ if you believe that you are in the grips of a fatal neurodegenerative disorder, rather than a treatable depression?”

Randolph does call for further research, particularly on why a significant percentage of former NFL players have subjective complaints of cognitive impairment. He suggests that cumulative brain damage from repetitive head injury may reduce a person’s cerebral reserve, making him or her more susceptible to the clinical manifestation of degenerative brain disorders later in life.

“If there are late-life consequences of repetitive head trauma from contact sports, it’s more likely to be due to diminished cerebral reserve, which leaves individuals with less ability to fend off the effects of neurodegenerative diseases,” Randolph says, although he intends to keep collecting and analyzing data to more fully explore the issue.