It’s Not Benign: Cannabis, Cognition, and Psychosis
Journal watch December 28, 2007 Deborah Cowley
Despite persistent questions about causality and the confounding of results, this past year has seen the strongest evidence to date of an association
Cannabis research published in 2007
45 studies whose primary subject is cannabis were published in 2007, up from 32 in 2006. Newest first. Back to the cannabis overview
Studies
Spatial working memory performance and fMRI activation interaction in abstinent adolescent marijuana users.
Psychology of Addictive Behaviors December 2007 Claudia B Padula, Alecia D Schweinsburg, Susan F Tapert
Previous studies have suggested neural disruption and reorganization in adult marijuana users. However, it remains unclear whether these effects persist in adolescents after 28 days of abstinence and, if they do, what Performance x Brain Response interactions occur. Adolescent marijuana users (n=17) and controls (n=17) aged 16-18 years were recruited from local schools. Functional magnetic...
Cannabis, Consciousness, and Healing
Contemporary Justice Review December 1, 2007 Wendy Chapkis 16 citations
Federal drug policy defines marijuana as a prohibited Schedule 1 substance—a dangerous drug carrying a high potential for abuse and no accepted medical use. This classification is largely due to the drug's well‐known psychoactive effects (‘the high’). Because of this, even medical marijuana advocates have tended to downplay the consciousness‐altering properties of cannabis when arguing for the...
DOI: 10.1080/10282580701677550 (opens in new tab)
Cannabis
Consciousness
Alliance
Drug
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Single and multiple doses of rimonabant antagonize acute effects of smoked cannabis in male cannabis users.
Psychopharmacology November 2007 Marilyn A. Huestis, Susan J Boyd, Stephen J Heishman et al.
A single 90-mg dose of the cannabinoid CB1 receptor antagonist rimonabant attenuates effects of smoked cannabis in humans. The objective of this study is to evaluate whether repeated daily 40-mg doses of rimonabant can attenuate effects of smoked cannabis to the same extent as a single higher (90 mg) dose. Forty-two male volunteers received one of three oral drug regimens in a randomized,...
El uso de cannabis aumentaría el riesgo de desarrollar un trastorno psicótico en el futuro
Evidencia actualizacion en la práctica ambulatoria November 1, 2007 David Orozco
2 20 00 07 7 EVIDENCIA -Actualización en la Práctica Ambulatoria 145 Objetivo Revisar sistemáticamente la evidencia científica acerca del uso de cannabis y la ocurrencia de episodios psicóticos o afectivos que perduran más allá de la intoxicación aguda. Fuente y selección de datosLos autores buscaron en las bases de datos Medline, Embase, CINAHL, PsycINFO, ISI Web of Knowledge
The neuropsychology of cannabis and other substance use in schizophrenia: review of the literature and critical evaluation of methodological issues.
The Australian and New Zealand journal of psychiatry November 2007 Carissa M Coulston, Michael Perdices, Christopher C Tennant
Research on the neuropsychology of substance use in schizophrenia has been steadily growing over the past decade. However, significant gaps remain in the knowledge of individual substances and their relationship to cognition in the schizophrenia spectrum disorders. Approximately 65 studies to date have directly examined this relationship. Of these, approximately 20 have focused on nicotine, 15...
Cannabis use and psychosis: the origins and implications of an association
Advances in Psychiatric Treatment October 31, 2007 John Macleod 6 citations
Evidence for the effectiveness of treatment or secondary prevention of psychotic illness such as schizophrenia is often disappointing. This situation reflects our limited understanding of the aetiology of psychosis. There is good evidence that both genetic and environmental factors are implicated but the precise identity of these is unclear. Cannabis use is one candidate as a possible,...
Genetic dissection of behavioural and autonomic effects of Delta(9)-tetrahydrocannabinol in mice.
PLoS Biology October 2007 Krisztina Monory, Heike Blaudzun, Federico Massa et al.
Marijuana and its main psychotropic ingredient Delta(9)-tetrahydrocannabinol (THC) exert a plethora of psychoactive effects through the activation of the neuronal cannabinoid receptor type 1 (CB1), which is expressed by different neuronal subpopulations in the central nervous system. The exact neuroanatomical substrates underlying each effect of THC are, however, not known. We tested locomotor,...
Functional imaging studies in cannabis users.
The Neuroscientist October 2007 Linda Chang, Edward P Chronicle
Cannabis remains the most widely used illegal drug in the United States. This update examines the available literature on neuroimaging studies of the brains of cannabis users. The majority of studies examining the acute effects of delta-9-tetrahydrocannabinol (THC) administration used PET methods and concluded that administration of THC leads to increased activation in frontal and paralimbic...
Cannabis-related psychosis: Presentation and effect of abstinence.
Indian Journal of Psychiatry October 2007 Vani Kulhalli, Mohan Isaac, Pratima Murthy
The correlation between cannabis and negative mental health outcomes has been unequivocally established. Nevertheless, there is still a great need to research different dimensions of cannabis-related disorders, among which the study of cannabis-related psychosis is very important. There is a dearth of research regarding phenomenology and effect of abstinence, particularly from India. This study...
DOI: 10.4103/0019-5545.37665 (opens in new tab)
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Cannabis
Drug-induced psychoses
Sex differences in the effects of delta9-tetrahydrocannabinol on spatial learning in adolescent and adult rats.
Behavioural Pharmacology September 2007 Young May Cha, Katherine H Jones, Cynthia M Kuhn et al.
Like other recreational drugs, cannabinoids may produce different effects in men and women. In this study we measured the effects of delta9-tetrahydrocannabinol (THC) on spatial learning in two groups that are underrepresented in drug research--females and adolescents. In the first experiment, adolescent (postnatal day 30) and adult (postnatal day 70) rats of both sexes were treated...
Cellular mechanisms underlying the anxiolytic effect of low doses of peripheral Delta9-tetrahydrocannabinol in rats.
Neuropsychopharmacology September 2007 Tiziana Rubino, Mariaelvina Sala, Daniela Viganò et al.
We investigated the effect of low doses of intraperitoneal Delta(9)-tetrahydrocannabinol (THC) on anxiety behavior in rats using the elevated plus maze (EPM). An anxiolytic effect was obtained in a range of doses between 0.075 and 1.5 mg/kg, the 0.75 dose being the most effective. Pretreatment with the CB1 receptor antagonist AM251 fully reversed THC's effect, suggesting CB1 receptors were...
Lack of behavioral sensitization after repeated exposure to THC in mice and comparison to methamphetamine.
Psychopharmacology September 2007 Stephen A Varvel, Billy R Martin, Aron H Lichtman
Recent evidence has provided support for the incentive-sensitization model of addiction, where repeated stimulation of neural reward circuits leads to a long-lasting sensitization of mesolimbic dopaminergic activity. This phenomenon has been demonstrated with many drugs of abuse, most often by measuring progressively increased activating effects of drugs on locomotor activity, thought to...
Anandamide levels in cerebrospinal fluid of first-episode schizophrenic patients: impact of cannabis use.
Schizophrenia Research August 2007 F Markus Leweke, Andrea Giuffrida, Dagmar Koethe et al.
Previous studies have shown that cerebrospinal fluid (CSF) from schizophrenic patients contains significantly higher levels of the endogenous cannabinoid anandamide than does CSF from healthy volunteers. Moreover, CSF anandamide levels correlated inversely with psychotic symptoms, suggesting that anandamide release in the central nervous system (CNS) may serve as an adaptive mechanism...
The toxicology of cannabis and cannabis prohibition.
Chemistry & Biodiversity August 2007 Franjo Grotenhermen
The acute side effects caused by cannabis use are mainly related to psyche and cognition, and to circulation. Euphoria, anxiety, changes in sensory perception, impairment of memory and psychomotor performance are common effects after a dose is taken that exceeds an individually variable threshold. Cannabis consumption may increase heart rate and change blood pressure, which may have serious...
The fatty acid amide hydrolase C385A (P129T) missense variant in cannabis users: studies of drug use and dependence in Caucasians.
American Journal of Medical Genetics. Part B, Neuropsychiatric Genetics July 5, 2007 Rachel F. Tyndale, Jennifer I Payne, Alexandra L Gerber et al.
A genetic variation in fatty acid amide hydrolase (FAAH), C385A (P129T), has been previously associated with risk for problem street drug use. FAAH is a mammalian enzyme that inactivates neuromodulatory-signaling lipids including the endogenous cannabinoid 1 receptor agonist anandamide. We investigated in adult Caucasians (N = 749) whether this FAAH variant altered the risk for trying, regular...
Cannabis use and symptom experience amongst people with mental illness: a commentary on Degenhardt et al.
Psychological Medicine July 1, 2007 John Macleod
A high proportion of people who have a serious mental illness also use non-prescribed psychoactive drugs. This association is perhaps most apparent, and possibly also has the greatest implications for health, in relation to tobacco use. In fact recognition of the special relationship between mental illness and smoking was recently reflected in exemption of psychiatric units from legislation to...
A comparison of symptoms and family history in schizophrenia with and without prior cannabis use: implications for the concept of cannabis psychosis.
Schizophrenia Research July 2007 J Boydell, K Dean, R Dutta et al.
There is considerable interest in cannabis use in psychosis. It has been suggested that the chronic psychosis associated with cannabis use, is symptomatically distinct from idiopathic schizophrenia. Several studies have reported differences in psychopathology and family history in people with schizophrenia according to whether or not they were cannabis users. We set out to test the hypotheses...
Visual scan paths in first-episode schizophrenia and cannabis-induced psychosis
Journal of Psychiatry and Neuroscience July 1, 2007 Philip J. Benson, Ute Leonards, Robert Lothian et al. 38 citations
OBJECTIVE: Patterns of successive saccades and fixations (scan paths) that are made while viewing images are often spatially restricted in schizophrenia, but the relation with cannabis-induced psychosis has not been examined. We used higher-order statistical methods to examine spatiotemporal characteristics of scan paths to determine whether viewing behaviour was distinguishable on a continuum....
MDMA attenuates THC withdrawal syndrome in mice.
Psychopharmacology July 2007 Clara Touriño, Rafaël Maldonado, Olga Valverde
3, 4-Methylenedioxymethamphetamine (MDMA) and cannabis are widely abused illicit drugs that are frequently consumed in combination. Interactions between these two drugs have been reported in several pharmacological responses observed in animals, such as body temperature, anxiety, cognition, and reward. However, the interaction between MDMA and cannabis in addictive processes such as physical...