Neurotransmitters are endogenous substances that transmit impulses from neuron to neuron via synapses. They are synthesized from various simple precursors, such as amino acids, a sufficient amount of which comes from food and is assimilated through several biosynthetic processes. Neurotransmitters are crucial to life, and any effect on them can change a person’s thinking and behavior. Some drugs act on neurotransmitters, and various mechanisms for different drugs carry out their effect on brain activity.
Their action is based on stimulating the release of catecholamines (noradrenaline, serotonin, dopamine) and inhibiting their reuptake. Some drugs can block or stimulate the production of a particular type of neurotransmitter (Sapolsky, 2005). In contrast, others prevent their accumulation in synaptic vesicles, depriving the membrane of the ability to retain them. Drugs that prevent neurotransmitters from binding to their receptors are called receptor antagonists. For example, schizophrenia drugs such as haloperidol, chlorpromazine, and clozapine are dopamine receptor antagonists in the brain (Sapolsky, 2005). Other drugs, however, deactivate the neurotransmitter after it has been activated, thereby prolonging its action time. Finally, drugs can also prevent the onset of action potentials by blocking the neural activity of the central and peripheral nervous systems. The use of drugs that block neuronal activity, such as tetrodotoxin, often ends in death.
The general effect of stimulants on the body is expressed in physical activity and vigor, increased mental performance, decreased appetite, drowsiness, fatigue, and improved mood. At the same time, irritability, anxiety, inadequate reactions, and insomnia occur. Large doses of stimulants may cause repetitive teeth grinding, weight loss, false tactile sensations, and tingling of facial skin (Sapolsky, 2005). An overdose can lead to dizziness, tremors, bowel spasms, chest pains, severe heart palpitations, and cause anxiety, aggressiveness, panic attacks, and paranoia. Anxiety and suicidal tendencies persist for several months.
Psychedelics are substances that have a psychotropic effect on a person’s emotional state, changing their consciousness. The drugs do not cause withdrawal, or vivid physical dependence. At the same time, such addiction is already formed from the first time. Over time the patient develops a degradation of personality (Sapolsky, 2005). The danger of psychedelics is an increase in latent mental illness – schizophrenia, manic-depressive psychosis, attacks of paranoia, and so on. In some cases, the harm of psychedelics is in a sharp change of mood and the emergence of depression, which can be so pronounced that, in some cases, it leads to suicide attempts.
The mechanism of action of antidepressants depends on the group to which a particular drug belongs. However, all antidepressants have one thing in common: the effect on neurotransmitters belonging to monoamines. Due to this, a patient suffering from depression improves his mood, increases mental alertness, apathy, melancholy, lethargy, anxiety, irritability, and nervousness decrease or disappear, sleep quality improves, and its phase structure and duration are normalized (Sapolsky, 2005). Antidepressants affect only the depressive background; in a healthy person, taking most antidepressants does not cause changes in consciousness. They do not affect a person’s intellect, cognitive abilities, or memory.
Psychoactive drugs temporarily affect a person’s neurochemistry, which in turn causes changes in their mood, cognition, perception, and behavior. Psychoactive drugs can affect the brain in different ways (Sapolsky, 2005). Each drug specifically affects one or more neurotransmitters or neuroreceptors in the brain. Psychotropic drugs regulate human mental functions: emotions, memory, thinking, behavior motivation, psychomotor activity, and mood. It is known that the use of psychotropic drugs reduces cognitive skills and has a detrimental effect on all organs and body systems, causing irreversible changes (Sapolsky, 2005). The central nervous system, through which all other organs and body systems are coordinated, is particularly affected.
Reference
Sapolsky, R. (Lecturer). (2005). Biology and Human Behavior: The Neurological Origins of Individuality 12 Lecture [DVD]. Web.