Part 2 book “Delusions - Understanding the Un-understandable“ has contents: The neurochemical connection, delusion-like phenomena in neurological disease, the salience theory of delusions, what a theory of delusions might look like. | 89 Chapter 6 The Neurochemical Connection As psychology struggled to make headway with delusions, another discipline close to the heart of psychiatry, pharmacology, was sending out signals that a different approach might be more successful. The psychopharmacological era began in 1952 with the discovery that a drug, chlorpromazine, brought about substantial clinical benefit in schizophrenia, where everything everything else from psychoanalysis to insulin coma therapy had previously failed. Not only did this and other antipsychotic drugs improve psychotic symptoms, it seemed that other drugs could also induce them in healthy people. This became clear a few years later when psychiatry finally accepted what had been staring it in the face for years, that amphetamine not- infrequently produced a state indistinguishable from schizophrenia in people who used it. Antipsychotic drugs exert their therapeutic effects by producing a functional decrease in brain dopamine; amphetamine and other stimulants cause a functional increase of the same neurotransmitter. These two complementary findings became the pillars of the dopamine hypothesis of schizophrenia, which reigned supreme for a quarter of a century, until a competitor arrived in the form of a drug with effects on another neurotransmitter. Phencyclidine, which had been introduced in the 1950s, was known to induce vivid subjective experiences in many patients who were given it as an anaesthetic or for pre- operative sedation, and it had even been investigated as a possible pharmacological model for schizophrenia. Later it became a drug of abuse and users started to turn up in emergency rooms in severe psychotic states. Later still it was found to act by blocking the N- methyl- D- aspartate (NMDA) receptor, one of several classes of glutamate receptor. The dopamine hypothesis survives to the present day despite a number of reversals of fortune. At the time of writing, the glutamate theory is facing an existential crisis,
