AD patients have been shown to have decreased GABA and SST immunoreactivity in the cerebral cortex (Davies et al., 1980; Grouselle et al., 1998), and in late-onset familial and sporadic AD, the risk gene apolipoprotein (apo) E4 polymorphism exacerbates SST dysfunction (Grouselle et al., 1998). Here, SST is linked to Alzheimer disease.