Effects of substance P on memory and mood in healthy male subjects

There is evidence from human and animal studies that substance P (SP) is involved in the etiopathology of depression and anxiety. Furthermore, animal studies have shown effects of SP on memory. In a double-blind, randomized cross-over study, 13 healthy young men received SP (1.5 pmol/kg/min) or placebo (NaCl) intravenously over 90 min at two different days. Before and during the infusion, symptoms of anxiety and depression were assessed by different self-rating questionnaires and cognitive functioning by the Auditory-Verbal Learning Test (AVLT) as well as by two subtests of the Test for Attentional Performance (TAP). Infusion of SP caused an increase of symptoms of inner tension and of anxiety as assessed by the Acute Panic Inventory (API) and a disturbance of short-term memory in the AVLT. The results may be interpreted as evidence for an anxiogenic and memory-disturbing effect of SP. Further studies will focus on the effects of SP in patients with depression, anxiety and cognitive disorders.