230 candidate genes (for example SERT gene), means OCD is polygenic
polygenic
means OCD is not caused by one single gene but by a combination of genetic variations that increase vulnerability
nedstadt
MZ twins have 68% concordance rate
neural explanations for ocd: neurotransmitters
serotonin - low levels lead too obsessive thoughts, these low levels are due to serotonin being removed too quickly before it can transmit its signal, SERT gene is responsible for serotonin transportation
neural explanations for ocd: neural structures
worry circuit - orbitofrontal cortex, basal ganglia system (caudate nucleus and thalamus)
worry circuit
communication between these structures appears to be over active in people with OCD
basal ganglia system
filters out minor worries coming from orbitofrontal cortex, if hyperactive - small worries get to thalamus, this goes back to orbitofrontal cortex which creates a loop of reoccuring obsessive thoughts - repetitive motor functions (compulsions) attempt to break this loop
parahippocampus gyrus
close to hippocampus, linked to OCD, which is responsible for regulating and processing unpleasant emotions
