Pyrroles belong to the group of compounds that are known under different names, such as HPU, kryptopyrroluria, KPU, which in the international literature also known as the ‘mauve factor’ or ‘china doll disease’. The name kryptopyrroluria is derived from the chemical compounds kryptopyrroles, which in a number of people can be found in the urine.

KPU is a disturbance in the breakdown of haem-containing compounds such as haemoglobin, myoglobin, cytochrome and many other. These substances are normally routed back through the bile in the intestine and excreted with the faeces. In KPU a part of these compounds excreted through the urine for a period of time because of deficits of stress-minerals and -vitamins. KPU is acquired and not genetically controlled.

Pyrroles belong to the chemical group of indoles. Already around 1900 the presence of indoles in the urine, was investigated. At the time, they sought to establish a link with the occurrence of psychological symptoms.

The investigation of indoles was intensified in 1961 in the United States after the urine was examined of 32 patients with schizophrenia. At no less than 27 patients pyrroles were found, which was then known as the ‘mauve factor’ because a positive result gave a lavender colour at the paper chromatography. Almost at the same time, researchers laid a link with another psychiatric disease, psychosis.

Other scientists examined in the mid-1960s a random group of people and psychiatric patients for the presence of the mauve factor. At eleven percent of non-psychiatric patients was kryptopyrrole found. In the group of psychiatric patients 42 percent was positive. The schizophrenia patients scored even higher: 52 percent had the mauve factor in the urine.

At the end of the 1960s Canadian researchers elucidated the chemical structure of the ‘mauve factor’ as kryptopyrrole. The whole of symptoms during that period was referred to as the ‘china doll disease’, a name which was derived from the China dolls with their white faces. Most patients with kryptopyrroluria had pale face that is more or less sunlight sensitive, so that they barely came out as the sun was shining.

The last important contribution the American psychiatrist Dr. C.C. Pfeiffer, who in 1987 wrote a book about psychiatric illnesses and schizophrenia (Mental Illness and Schizophrenia). In this he devoted extensive attention to the meaning of kryptopyrrole for the psychiatric field.

In the vision of Dr. John Kamsteeg in particular, Dr. Pfeiffer has carried out important work, but it is a pity that kryptopyrroluria was placed in the corner of the psychiatric illnesses. “That it has been detected in psychiatry, has harmed the acceptance of this clinical picture,” he says in the book have you HPU? “Psychic complaints may form part of the set of symptoms. But the severe psychiatric disorders you see really only in people who have a very high concentration in their urine of the mauve factor.”