Limbic dysfunction can be associated with infection One other angle here is infection. The limbic system can be injured and its function altered by infections. Lyme Disease is one condition where limbic brain area damage has been reported. Probably various encephalitis agents can over-sensitize limbic functions. Also, chemical injury (toxins getting through a leaky BBB) and physical trauma can alter limbic function. Here is a study of chronic Lyme patients after an antibiotic therapy. Their brain function is altered, including altered gray matter and limbic area dysfunction. In this case there is hypoactivity, but the point is simply that infection can explain some limbic dysfunctions.