Cannabis affects the severity of schizophrenic symptoms: results of a clinical survey

Abstract

SynopsisData on the history of cannabis use and a spot urine test for cannabinoids were obtained for 137 schizophrenics in treatment. Subjects who were using cannabis during the 6-month observation period presented with a significantly higher degree of delusional and hallucinatory activity than those who did not. Moreover, the group using cannabis made a higher average number of visits to the hospital during the same period. The status of cannabis use appeared to contribute to such variance more than did other relevant factors (age, stage of the illness, amount of medication prescribed, occasional use of other psychoactive substances).

The endocannabinoid system: a physiological perspective on its role in psychomotor control

“…Heavy cannabis use may precipitate a toxic psychosis in individuals with a previous history of psychotic illness (Negrete et al, 1986;Andréasson et al, 1987;Linszen et al, 1994). This observation has led to propose a 'cannabinoid hypothesis of schizophrenia', which postulates that the psychotic symptoms of this disease result from a over-activity of the endogenous cannabinoid system (Emrich et al, 1997).…”

Development of CIE-10 and DSM-IV cannabis disorders / Desarrollo de la CIE-10 y el DSM-IV para trastornos por cánnabis

“…Aducen que sólo tendría sentido postulando la necesidad de una personalidad premórbida para la esquizofrenia, concepto que ha ido perdiendo adeptos en las últimas décadas. Si los cannabistas tienden a presentar síntomas positivos de esquizofrenia y además de aparición aguda (Cleghorn et al, 1991;Knudsen y Vilmar, 1984;Negrete et al, 1986;Treffert, 1978;Weil, 1970), entonces no cabe pensar en una fase prodrómica tan importante y dilatada como para permitir instaurarse un cannabismo duradero y causar así esquizofrenia, por intenso que haya sido el consumo (Allebeck et al, 1993). A menos que se aduzca una personalidad premórbida de muy prolongada latencia, difícil de demostrar.…”

“…En los años 80 fue defendida con gran vehemencia por Juan Carlos Negrete (Negrete, 1988), catedrático de psiquiatría en Montreal (Canadá). Su grupo hizo uno de los pocos estudios caso-control entonces disponibles, pero los síntomas psicóticos fueron evaluados retrospectivamente, utilizando archivos hospitalarios (Negrete et al, 1986). Un estudio anterior (Rottanburgh et al, 1982) también controlado adolecía del breve periodo de observación de una semana.…”

“…Desde el punto de vista sintomatológico (Linszen et al, 1994), los estudios sobre cánnabis y esquizofrenia concuerdan en tres importantes hallazgos: 1) que al consumirse cánnabis hay incremento de síntomas psicóticos positivos, siendo este incremento dosisdependiente (Cleghorn et al, 1991;Knudsen y Vilmar, 1984;Negrete et al, 1986;Treffert, 1978;Weil, 1970);…”

Schizophrenia, Co-occurring Substance use Disorders and Quality of Care: The Differential Effect of a Managed Behavioral Health Care Carve-out

“…In persons with schizophrenia, co-occurring SUDs have been associated with more severe symptoms (Alterman, Erdlen, & Murphy, 1982;Barbee et al, 1989;Hays & Aidroos, 1986;Negrete et al, 1986), greater risk of suicide (Cohen, Test, & Brown, 1990;Landmark, Cernovsky, & Merskey, 1987), more frequent psychotic relapses (Linszen, Dingemans, & Lenior, 1994;Sokolski et al, 1994), and more frequent inpatient hospitalization (Carpenter, Heinrichs, & Alphs, 1985;Drake & Wallach, 1989;Hunt, Bergen, & Bashir, 2002)-even if adherent to medications (Hunt, Bergen, & Bashir, 2002). Additionally, longstanding barriers to treatment and support services for patients with co-occurring psychiatric disorders and SUDs have been documented (Substance Abuse and Mental Health Services Administration, 2002).…”