Neurological Correlates

Sciencewatch has a good map of OCD research: (click figure to go to interactive map):

With OCD, it looks like some forms correlate with the glutamate system. Putting it all together, possibly the glutamate transporters in the striatum get “stuck” because both sides of the synapse are sort of glutamate-challenged. It might be a solute carrier protein which is somewhat inactive on one side, and then a glutamate receiving protein that is somewhat inactive on the other. I wonder if there is also something of a solute carrying protein for a metal ion, as the rhythmic activity seems to be associated with OCD somewhat. That could be a solute carrier protein as well, such as SLC26A1, which is involved in iodine transport (and also Pendred syndrome, which is deafness).

Solute carrier proteins, like SLC1A1 , may be modified in families having OCD.  This is interesting because “high-affinity glutamate transporters play an essential role in transporting glutamate across plasma membranes. In brain, these transporters are crucial in terminating the action of the excitatory neurotransmitter glutamate and in maintaining extracellular glutamate concentrations below neurotoxic levels.” OMIM*133550

SAPAP3 is a gene associated with pathological grooming, like, pathologic nail biting, pathologic skin picking, and/or trichotillomania.  “SAPAP3 is the only member of a glutamate-regulating family of proteins that is present in large amounts in the striatum. It is part of the machinery at the receiving end of the connections between brain cells, where the neurotransmitter binds to receptors, triggering increased activity among the cells.  The researchers found that lack of SAPAP3 genes dampened the increased activity usually caused by glutamate and stunted the development and functioning of circuit connections.” (Life Scientist, AU 08.23.07).

Update 04.04.09: The Financial Times has an article, “Is there a bit of OCD in all of us?” discussing the current state of OCD public awareness, therapy, and outreach. The author interviews people with OCD, as well as clinicians who treat it.  The article didn’t distinguish between the various subtypes as pointed out in research, and it would be useful, I think, for people with OCD to have an awareness that one OCD-size doesn’t fit all. Presumably there will be personalized medicine at some point, for those seeking treatment.