Psychopharmacology is the scientific study of the effects drugs have on mood, sensation, thinking, and behavior. The field of psychopharmacology studies a wide range of substances with various types of psychoactive properties, the term psychopharmacology was probably first coined by David Macht in 1920. Psychoactive drugs interact with particular target sites or receptors found in the system to induce widespread changes in physiological or psychological functions. The specific interaction between drugs and their receptors is referred to as action, and the widespread changes in physiological or psychological function is referred to as drug effect. These drugs may originate from sources such as plants and animals. Not often mentioned or included in the field of psychopharmacology today, are psychoactive substances not identified as useful in mental health settings or references. These substances are naturally occurring, but nonetheless psychoactive, and are identified through the work of ethnobotanists and ethnomycologists. Nevertheless, some, such as psilocybin and mescaline, have provided a basis of study for the compounds that are used and examined in the field today. Hunter-gatherer societies tended to favor psychedelics, dissociatives and deliriants, the exact drug used depends on what the particular ecosystem a given tribe lives in can support, and are typically found growing wild. These societies generally attach spiritual significance to such use. With the dawn of the Neolithic and the proliferation of agriculture, among them were opium, cannabis, and alcohol derived from the fermentation of cereals and fruits. Most societies began developing herblores, lists of herbs which were good for treating various physical and mental ailments, for example, St. Johns Wort was traditionally prescribed in parts of Europe for depression, and Chinese medicine developed elaborate lists of herbs and preparations. These and various other substances that have an effect on the brain are used as remedies in many cultures. The dawn of contemporary psychopharmacology marked the beginning of the use of drugs to treat psychological illnesses. It brought with it the use of opiates and barbiturates for the management of acute behavioral issues in patients, in the early stages, psychopharmacology was primarily used for sedation. After the 1960s, the field of psychiatry shifted to incorporate the indications for and efficacy of pharmacological treatments, the 1970s and 1980s were further marked by a better understanding of the synaptic aspects of the action mechanisms of drugs. However, the model has its critics, too – notably Joanna Moncrieff, psychoactive drugs exert their sensory and behavioral effects almost entirely by acting on neurotransmitters and by modifying one or more aspects of synaptic transmission. Neurotransmitters can be viewed as chemicals through which neurons primarily communicate, the other central method through which drugs act is by affecting communications between cells through hormones
An arrangement of psychoactive drugs
The common muscimol-bearing mushroom Amanita muscaria, also known as the "Fly Agaric"