I became interested in the philosophical discussions surrounding schizophrenia while I was taking my clinical courses for my psychology professional degree in Chile. While attending some patients, I realized that delusions seemed to have a strong adaptive function. Although this is a matter that needs further argumentation, I think that systematic research on the structure of certain delusions can facilitate better understandings of their role (Roberts, 1992) and, quite importantly, to improve therapeutic intervention (Guidano, 1991). An example of this can be offered by looking at the structure of thought insertion, an abnormal conscious experience commonly regarded as suggestive of schizophrenia (Mullins & Spence, 2003).
Philosophers have become interested in thought insertion for its puzzling character. For instance, this symptom seems to challenge the immunity principle, and the inseparability thesis. In addition, thought insertion is a challenge to common conceptions regarding the relationship between self-awareness and phenomenal consciousness (Billon, 2013). Roughly speaking, patients suffering from thought insertion complain of being aware of thoughts which are not their own intruding into their mind.
The structure of this abnormal experience is quite complex, however the specificity of episodes of thought insertion offers an interesting opportunity to link delusions with their adaptive role in human psychological life. The idea is that patients experience as alien only a certain kind of thought-content, but not all kinds (Gallagher, 2004). The patients’ experiences seem to be quite specific, and most of the time the contents of them are associated with significant others or with certain themes that are affectively important to their biographies. For instance, Saks (2007) describes her own first episode of thought insertion by making reference to contents that seem to be affectively important to her own personal history (self-image, relationship with their parents, etc.).
The relationship between the specificity of the contents of inserted thoughts with the personal history of the patients seems to suggest that, at least this type of delusion would have something I shall call an 'affective adaptiveness role’ i.e. delusions serve the patient's need to deal with affectively intolerable experiences. It seems plausible to think that some degree of affective significance for the patients may be involved in the genesis of thought insertion and that clinicians and philosophers should explore further this matter in order to improve therapeutic intervention.