Posted by alexandra_k on December 21, 2004, at 18:00:06
In reply to Re: 1.4, posted by smokeymadison on December 21, 2004, at 16:54:20
>is there any evidence that it is the affective pathway that is messed up in these delusional subjects?
The 'affective pathway' is just the name they have given to the pathway that produces the affective (skin galvanisation) response. Subjects with cerebral injury and the Capgras delusion do not produce the affective response, therefore there is a breakdown in their affective pathway.
(At this stage the positing of an affective pathway has a hint of circularity about it)
Ok. Nows the time to fess up, they really are focused on Capgras and Fregoli delusions that occur in response to cerebral injury. There is a (fairly) localised site of damage, which leads to a (fairly) specific deficit (the lack of affective response) and that seems to produce a fairly specific delusional belief. I like this because I am interested in the relationship between neurological, cognitive, and intentional (common sense) explanation - though its relevance for delusions that occur for other reasons (e.g., Schizophrenia) remains unclear... It is unclear whether subjects who develop the Capgras delusion within the context of schizophrenia will be found to have a similar lack of affective response.
> i mean that not everyone in severe emotional distress becomes delusional, but for those who are delusional, it started with extreme emotion.
This sounds like a two-factor model though. What I want to consider is whether there is something different about the anomalous experiences (or emotional distresses, if you like) of subjects who do and do not develop delusions. In the Cotard delusion the delusion seems to result from a LOSS of emotion if you will, and thus it doesn't seem to be extreme distress that is so relevant. That being said, Maher thinks that the difference between delusional and nondelusional subjects is a function of the intensity and duration of the anomalous experience. Maybe you have sympathy with this line?
I have a little list of delusions that I have compiled...
1)Cotard 'I am dead'
2)Capgras 'My wife has been replaced by an impostor'
3)Fregoli 'People I know are disguising themselves as strangers and are following me around'
4)Unilateral Neglect 'Thats not my arm - It's yours!'
5)Reduplicative Paramnesia 'My husband died long ago - but he is also a current patient on this ward'
6)Mirrored Self Mis-Identification 'There is a person in the mirror who follows me around'
7)Thought Insertion 'Someone elses thoughts are being inserted in my mind'
8)Alien Control 'Someone else is initiating my actions'
9)Thought Withdrawal 'Someone is taking thoughts from my mind'
10)Thought Broadcast 'Other people can hear my thoughts'
11)Reference 'The tables signified that the world was coming to an end'
12)Grandeur 'I am god'
13)Persecution / Paranoid 'The FBI are out to get me'
14)Jealousy 'My partner is cheating on me'
15)Erotomania 'Winston Peters is in love with me'
16)Somatic 'I don't have any internal organs'.
Now most theorists attempt to explain 7-16 which typically occur in schizophrenic delusions. The recent neurological findings of subjects with cerebral injury, however has led to theorists working within the framework of cognitive neuro psychology to have a go at 2-6. I think it is fair to say that most accept the explanation of 1 that I have already given. An explanation of 2-3 can be fairly easily adapted to explain 7-8, though it would be much nicer if we could get an explanation of 9-10 to flow out of this I need to think about this much more...
Anyways. my point is that typically explanations of delusion were psychodynamic. Psychodynamic explanations cannot hope to account for delusion in the case of cerebral injury, though, and have poor prospects for explaining why damage to the right hemisphere seems to be implicated.
Psychologists have thus started from the top of the list while psychiatrists have started from the bottom. it is unclear whether an account within one framework can be applied to all. Maybe neurological delusions will need a different kind of explanation to psychiatric ones.
But Freud didn't get to be famous by limiting his speculations to what he wanted to do with his own mother... we should at least try...