My experience on this forum has been that there is more knowledge and confidence in understanding depersonalization as opposed to derealization. It also seems to me that many patients and members of this forum find derealization symptoms much more ominous due to the lack of information on the "visual aspect" of the disorder, to use forum-terminology. This is why I am making this post.
I have taken the following information from a relatively recent study (2018) with the title "Neuromolecular basis of faded perception associated with unreality experience" by Yokokawa et al. Please read the paper in its entirety, my interpretation may inevitably be inadequate/flawed[link].
The study makes the basic claim that derealization symptoms are mediated by dopaminergic activity in the striatum, please see the paper for how they reached this conclusion. Whats more, the study also implies that this piece of information is in line with the fronto-limbic model for depersonalization proposed by Anthony David, and the low dopamine is likely caused by an inhibibotry mechanism in the frontal lobes.
- "We discovered that the individual differences of dopamine D2 receptor availability in executive striatum were positively associated with activities of the right middle frontal gyrus (BA46), a part of the dorsolateral prefrontal cortex (DLPFC), and the left parietal cortex for the subjective faded condition."
- "the current finding indicates that individuals with lower endogeneous dopamine synthesis show higher activity in the frontoparietal network for subjective faded perception, and the lower dopamine may invade to build internal models of the predicted world, observed as the unreality feeling in the current study."
- "Furthermore, over the last two decades, a strong association of frontal and parietal activity and visual awareness has been established. A number of studies have shown that frontoparietal activity is associated with changes in the contents of visual consciousness."
So dopamine is low, but not because of neurodegeneration or toxicity, but because of an inhibitory mechanism that has been proposed and accepted for some years now.
The reference to the previous research is made here:
- "Previous neuroimaging studies of depersonalization disorder patients observed increased activities in the frontal and parietal cortex, and proposed that the emotional numbing or detachment in these patients was associated with the hyperactive top-down control system that inhibits emotional responses. DLPFC is also associated with the experience of presence in a virtual reality environment, where the higher activity in DLPFC was associated with the lower experience of presence and reality."
The study also makes reference to the attentional mechanism which I have in a previous post [link] speculated is central in the disorder.
- "Frontal and parietal cortex, where the former is anatomically connected with executive striatum and both are functionally connected with striatum, compose the top-down attentional control system."
All in all the study concludes:
- "Taking together both the observations of the striatal dopaminergic transmission and the proposed frontoparietal system, it could be speculated that the unreality experience based on subjective faded perception is influenced by the interaction between striatal dopaminergic transmission that plays a role in broadcasting the expectation-based sensory information to the cortex and the frontoparietal network, which in turn are necessary for conscious perception of fadedness and for the top-down allocations based on the subjective faded perception induced by the experimental settings of the current study."