Abnormal brain functional network dynamics in <scp>obsessive–compulsive</scp> disorder patients and their unaffected <scp>first‐degree</scp> relatives

We utilized dynamic functional network connectivity (dFNC) analysis to compare participants with obsessive–compulsive disorder (OCD) with their unaffected first‐degree relative (UFDR) and healthy controls (HC). Resting state fMRI was performed on 46 OCD, 24 UFDR, and 49 HCs, along with clinical assessments. dFNC analyses revealed two distinct connectivity states: a less frequent, integrated state characterized by the predominance of between‐network connections (State I), and a more frequent, segregated state with strong within‐network connections (State II). OCD patients spent more time in State II and less time in State I than HC, as measured by fractional windows and mean dwell time. Time in each state for the UFDR were intermediate between OCD patients and HC. Within the OCD group, fractional windows of time spent in State I was positively correlated with OCD symptoms (as measured by the obsessive compulsive inventory‐revised [OCI‐R], r = .343, p
We identified several dFNC differences in OCD and UFDR that may be useful for establishing biomarkers of an OCD endophenotype. First, OCD patients had abnormal temporal properties which correlated with clinical features, which were shared with their UFDR. Second, we found similar connectivity patterns for UFDR and OCD within a dFNC state characterized by between‐network integration. These results provide new insights into the pathophysiology of OCD patients and indicate dynamic functional connectivity measures that could be used as biomarker to identify those at risk.