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

What Was Tested

The paper reports a study of Substance P, published as a randomized controlled trial.

There is evidence from human and animal studies that substance P (SP) is involved in the etiopathology of depression and anxiety.

Who Took Part

The study group was 13 men.

The age groups tagged for this paper are adults, men only.

How the Study Was Run

The design is described as randomized, double-blind, placebo-controlled and crossover.

Random assignment meant chance, not the researchers, decided who got Substance P and who got the comparison, which limits bias.

Neither the men nor the staff measuring them knew who was on Substance P, so expectations could not easily colour the readings.

The comparison arm used a placebo, so changes seen with Substance P could be set against what happens without it.

Each person switched between Substance P and the comparison at some point, usually with a gap in between.

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).

What Was Measured

PubMed files the paper under topics including Affect, Anxiety, Attention, Autonomic Nervous System, Depression, Memory, Short-Term and Mental Recall.

What This Means in Plain Language

The paper is a randomized, double-blind and placebo-controlled study of Substance P in 13 men.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

The publication is from 2007 (Human psychopharmacology), a journal based in England.

More context: the Substance P compound page, all human trials.