PsychopharmacologyDecember 2005Paul J Fletcher, Catherine C Tenn, Zoë Rizos et al.
Repeated exposure to psychomotor stimulants can lead to sensitization to their effects, and sensitization has been implicated in the pathophysiology of schizophrenia and drug abuse. These disorders are characterized by cognitive deficits, particularly in prefrontally mediated executive function. The present experiments were conducted to investigate the effects of sensitizing regimens of...
There is a pressing need in the substance abuse field for more comprehensive models of etiology and treatment that address the complex issues of addiction, including the biological, social, cultural, spiritual and developmental needs of individuals and groups. This article presents a theoretical framework for an integral approach to substance abuse that expands on the existing biopsychosocial...
18-Methoxyroconaridine (18-MC), a synthetic derivative of ibogaine, reduces morphine self-administration and alleviates several signs of acute opioid withdrawal in rats. Although there is already well documented evidence of the mechanism mediating 18-MC's action to reduce the rewarding effects of morphine, nothing is known about the mechanism responsible for 18-MC's attenuation of opioid...
To investigate if associations between cannabis use and psychotic symptoms occur independently, or occur as a consequence of previous-other types of-psychopathology. A 14-year follow-up study of 1580 initially 4- to 16-year-olds who were drawn randomly from the Dutch general population was conducted. At initial assessment, psychopathology was assessed with the Child Behavior Checklist. Across...
Previous research indicates that long-term meditation practice is associated with altered resting electroencephalogram patterns, suggestive of long lasting changes in brain activity. We hypothesized that meditation practice might also be associated with changes in the brain's physical structure. Magnetic resonance imaging was used to assess cortical thickness in 20 participants with extensive...
The hippocampal dentate gyrus in the adult mammalian brain contains neural stem/progenitor cells (NS/PCs) capable of generating new neurons, i.e., neurogenesis. Most drugs of abuse examined to date decrease adult hippocampal neurogenesis, but the effects of cannabis (marijuana or cannabinoids) on hippocampal neurogenesis remain unknown. This study aimed at investigating the potential regulatory...
Hallucinogens are widely used, both by drug abusers and by peoples of traditional cultures who ingest these substances for religious or healing purposes. However, the long-term residual psychological and cognitive effects of hallucinogens remain poorly understood. We recruited three groups of Navajo Native Americans, age 18-45: 1) 61 Native American Church members who regularly ingested peyote,...
Cocaine can induce transient psychotic symptoms. We examined the phenomenology of such cocaine-induced psychosis (CIP) using a modified version of the Scale for Assessment of Positive Symptoms (SAPS), a well-validated instrument for the assessment of schizophrenic psychosis. We developed a new instrument, the Scale for Assessment of Positive Symptoms for Cocaine-Induced Psychosis (SAPS-CIP),...
Many complex and interesting phenomena in nature are due to nonlinear phenomena. The theory of nonlinear dynamical systems, also called 'chaos theory', has now progressed to a stage, where it becomes possible to study self-organization and pattern formation in the complex neuronal networks of the brain. One approach to nonlinear time series analysis consists of reconstructing, from time series...
Acute 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") treatment induces learning deficits in different animal models. In a passive avoidance learning task in rats, previous studies suggested a role for Ca2+/calmodulin-dependent protein kinase II (CaMKII) and N-methyl-D-aspartate (NMDA) receptors in the acute learning impairment. As cognitive deficits by "ecstasy" in humans have been only...