Addictive disorders are characterised by a tendency to respond in an increasingly automatic way to the presence of certain stimuli or goals: the ability to respond differently to certain circumstances is reduced. In a sense, it could be said that we are programmed to learn to respond in this way, polarising means and goals. Therefore, giving up an addiction always involves unlearning and/or relearning a behaviour.

When, after a relatively small stroke (a thrombosis or a stroke), a person gives up an addictive behaviour almost unintentionally and effortlessly, it follows that the injured part of the brain played a necessary role in that behaviour. This is what they have done in the present study: they analysed the lesions of 34 people who, after a stroke, no longer met the criteria for nicotine dependence.

They found that, although the brain lesions occurred in a variety of areas, certain connectivity profiles could be established: rather than nuclei, circuits were affected. In addition to the insula, the dorsal cingulate, the dorsolateral prefrontal cortex, the ventro-medial prefrontal cortex (here the role would be reversed) and their respective mirror references in the striatum seem to play a necessary role.

In addition, these affected connectivity profiles were relatively similar to those described for people with alcohol dependence, which could perhaps allow us to extrapolate the results to other addictive disorders.

Knowing which brain structures and electrical connections - with their corresponding chemical neurotransmitters - play a key role in addictive behaviours (some of which are already known) could open up new therapeutic possibilities in the medium to long term.