Dr. Robert Cantu on the Link Between Brain Trauma and Addiction

Dr. Robert Cantu has been one of the go-to scientists on the issue brain trauma. With the passing of Derek Boogaard, Rick Rypien, and Wade Belak, a new connection is being made concerning its effect on behavior. The latter two NHL players were apparently suffering from depression at the time of their deaths (Rypien's was a suicide), while Boogaard's death was a result of a mixture of painkillers, and alcohol. The untimely death of these men occurred within four months of each other. For Dr. Cantu, this suggests a pattern. When asked how suicide could be associated with CTE, Cantu, in speaking with CBC News, was very blunt: 

Because the difficulty handling impulses and the difficulty with emotions, especially depressive emotions, are impaired with CTE. That's why depression is very common with CTE.

Another pattern in this particular case is that each player was an NHL "enforcer": on ice guardians and tough guys who used to play significant roles to the game of hockey, historically speaking, but who have been actively phased out since the presence of NHL commissioner Gary Bettman. Dr. Cantu continues expands on the link between brain trauma and addiction:

The medial temporal lobe, as I said, is associated with addictive behaviours and alcohol and drug abuse are addictions. So it is very consistent. And we find that addictions are very common in people with CTE and we find that some of the brains that come our way, came our way not because of a conscious suicide but because somebody was involved with drugs and/or alcohol and the combination became lethal.

On whether enforcers are more likely to suffer from brain injury, the answer is fairly obvious, and in keeping with what seems to be the truth of concussions, which is that they occur during the middling trauma as opposed to the high impact sort. You only have so many neurons, and in particular, as Wired's Jonah Lehrer communicated to me last week, you only have so many (which is to say so very few) of those that routinely correspond with decision making. 

However, linking brain trauma with addiction might be misleading even disregarding that correlation is not causation. Especially in the case of Boogaard, Belak, and Rypien. The three men accounted for a total of 12 fights last season (7 from Boogaard, 2 from Belak, and 3 from Rypien). It's worth asking to what degree an unstable individual chooses an unstable role to begin with. 

When it comes to the brain, no concept is more complex than causality. The brain is not a compass. On its own, drug use has been shown to play a role on the brain in keeping with the effects of brain injury. And on the nature of addiction itself, there's a wide body of work revealing how some people are simply at a higher risk of substance abuse than others. None of this is conclusive, and none of this is meant to downplay the very real concern of brain trauma in sports, but in the relationship between the brain and behavior, we should be looking to understand the whole picture, and that picture hasn't been painted just yet.