Psoralidin raised 5-hydroxytryptamine and 5-hydroxyindoleacetic acid levels in the brain.

Other evidence includes reduced levels of a breakdown product of serotonin, 5-Hydroxyindoleacetic acid, in the cerebral spinal fluid.

Instead, it breaks down into 5-hydroxyindoleacetic acid (5-HIA), an organic acid that may be harmful in high amounts.

In 1963 Tyler and Smith found that this mushroom contains serotonin, 5-HTP and 5-hydroxyindoleacetic acid.

One product of serotonin breakdown is 5-hydroxyindoleacetic acid (5-HIAA), which is excreted in the urine.

In most patients, there is an increased urinary excretion of 5-HIAA (5-hydroxyindoleacetic acid), a degradation product of serotonin.

Cerebral spinal fluid (CSF) analysis showed a two-fold increase of homovanillic acid and 5-hydroxyindoleacetic acid immediately following exercise compared to normal levels.

Particularly in the striatum of the prenatally stressed male pups showed an increase in vanilmandelic acid, dopamine, serotonin, 5-hydroxyindoleacetic acid which all can affect sexual behavior.

Tormey WP, FitzGerald RJ: The clinical and laboratory correlates of an increased urinary 5-hydroxyindoleacetic acid.

A recent meta-analysis of 20 studies showed a correlation between ASPD and serotonin metabolic 5-hydroxyindoleacetic acid (5-HIAA).

Low plasma concentrations of DHA predict low concentrations of cerebrospinal fluid 5-hydroxyindoleacetic acid (5-HIAA).

With a certain degree of clinical suspicion, the most useful initial test is the 24 hour urine levels of 5-HIAA (5-hydroxyindoleacetic acid), the end product of serotonin metabolism.

It is now widely known that cytotoxic chemotherapeutic agents cause a detectable increase in blood levels of serotonin (5-HT) and its major metabolite, 5-Hydroxyindoleacetic acid (5-HIAA).

The diagnosis of carcinoid syndrome (a syndrome associated with flushing, diarrhea, bronchoconstriction, cardiac valvular lesions, and telangiectasia) is aided by demonstrating elevated 24-hour urinary 5-hydroxyindoleacetic acid levels.

Pharmacologic management: Somatostatin analogue (octreotide) has been demonstrated to relieve symptoms of malignant carcinoid syndrome in the great majority of patients, with significant reduction of 5-hydroxyindoleacetic acid (5-HIAA) levels.

Impulsive behavior, and especially impulsive violence predisposition has been correlated to a low brain serotonin turnover rate, indicated by a low concentration of 5-Hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF).