- Expressed in neurons and glia by LPS, IFN-γ or stress – generally inhibits neurons (T24–T26) - IL-6 can modulate synaptic transmission (T27, T28) - Activates glial metabolism and reduces neuronal metabolism (T29) - Regulates neuronal development, growth and regeneration (T30, T31) - Contributes to sickness behaviors and anxiety (T32) - Involved in schizophrenia, depression (T33) - Plasma and CSF levels increased by LPS, IFNs, IL1β (T34) - Induces changes in synaptic proteins contributing to ethanol dependence (T35, T36). Here, IL6 is linked to major depressive disorder.