Exploring Neuroplasticity: The Role of LSD, Methamphetamine, Cannabis, and Ketamine in Psychiatric Disorders

Abstract

Psychoactive substances are chemical compounds that cause emotional and behavioral changes by altering perceptions and cognition. These substances can affect communication between brain cells and synaptic connections, thereby influencing neuroplasticity. Neuroplasticity is a key mechanism underlying various psychiatric disorders such as depression, anxiety, and post-traumatic stress disorder. The findings suggest that psychoactive substances could open new avenues in the field of neuropsychiatry. However, it is emphasized that these substances must be used safely and under controlled conditions, with consideration given to their side effects and risks, and more clinical research is needed. This review discusses the effects of psychoactive substances such as lysergic acid diethylamide, methamphetamine, dimethyltryptamine, cannabis, ketamine, and psilocybin on neuroplasticity, and how these effects could be beneficial in the treatment of depression, anxiety, and other psychiatric disorders.

Introduction

Psychological disorders are generally defined as illnesses that manifest through abnormal behaviors, emotions, and thoughts.[1] The types of psychological disorders include anxiety disorders, post-traumatic stress disorder (PTSD), schizophrenia, obsessive-compulsive disorder (OCD), personality disorders, mood disorders, and childhood disorders.[2]

Anxiety Disorder

Anxiety disorder refers to a condition in which an individual experiences a high level of anxiety and fear in response to events that may or may not happen, to the extent that it seriously threatens their daily functioning and well-being.[3]

Obsessive-Compulsive Disorder

Obsessive-compulsive disorder is a DSM-5-defined disorder characterized by intrusive thoughts that cause distress, and repetitive behaviors performed in response to these thoughts.[4]

Mood Disorders

Mood disorders are a group of conditions in which an individual experiences significant emotional fluctuations, including manic (extremely active) or depressive (profoundly low energy) episodes. Suicidal thoughts are also associated with these disorders.[5]

Post-Traumatic Stress Disorder

Post-traumatic stress disorder is a disorder that develops after intense traumatic experiences such as war, sexual assault, or natural disasters. Symptoms include negative thoughts, emotional numbness, and social isolation.[6]

Schizophrenia

Schizophrenia is a disorder that significantly disrupts daily life and is characterized by delusions, hallucinations, and severe difficulties in emotional and behavioral regulation. Genetic factors also play an important role in its development.[7]

Dissociative Disorders

Dissociative disorders are a group of conditions in which an individual experiences a loss of identity integrity and detachment from reality.[8]

After researchers proposed the theory known as the monoamine hypothesis, they suggested that depression is caused by an imbalance among the chemicals responsible for communication between neurons.[9] Neurotransmitters are chemical substances that facilitate communication from one cell to another by crossing junctions called synapses. These molecules function as either excitatory or inhibitory agents.[10]

Antidepressants modulate serotonin (5-hydroxytryptamine, 5-HT) in the brain and enhance serotonergic transmission to the spinal cord. Among the various types of antidepressants are selective serotonin reuptake inhibitors, serotonin-norepinephrine reuptake inhibitors, norepinephrine-dopamine reuptake inhibitors, tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs), and noradrenergic and specific serotonergic antidepressants. Most of these drugs increase the concentration of monoamine neurotransmitters (serotonin, norepinephrine, and dopamine) in neural tissue or act as agonists at their receptors. There are also antidepressants with different mechanisms of action.[11]

PSYCHOACTIVE SUBSTANCES

The use of psychedelics dates back to 1897 when Arthur Heffter isolated mescaline from the peyote cactus.[12] Additionally, magic mushrooms containing psilocybin, which are widely found across the world, appear to have been commonly used.[13]

The Eleusinian Mysteries, known as mystical and sacred rituals in Ancient Greece, were fundamentally based on special mixtures containing psychoactive compounds of the time. These ceremonies were a form of ritual that ancient societies turned to in order to experience spiritual transformation. Researchers suggest that participants in the Eleusinian Mysteries used various plant- and mushroombased psychoactive substances to induce mystical awareness and a sense of unity. As for psychedelics, lysergic acid diethylamide (LSD) was first synthesized by Albert Hofmann in 1938 at the Sandoz laboratory in Switzerland.[14,15]

Mushrooms containing psilocybin, commonly known as “magic mushrooms,” grow across a wide geographic range around the world and have been observed to be used by various cultures.[