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Chronic drug exposure and drug withdrawal induce expressive neuronal plasticity which could be considered as both functional and pathological responses. It is well established that neuronal plasticity in the limbic system plays a pivotal role in relapse as well as in compulsive characteristics of drug addiction. Although increases in FosB/DeltaFosB expression constitute one of the most important forms of neuronal plasticity in drug addiction, it is unclear whether they represent functional or pathological plasticity. It is of noteworthy importance the individual differences in the transition from recreational use to drug addiction. These differences have been reported in studies involving the ethanol-induced locomotor sensitization paradigm. In the present study we investigated whether sensitized and non-sensitized mice differ in terms of FosB/DeltaFosB expression. Adult male outbred Swiss mice were daily treated with ethanol or saline for 21 days. According to the locomotor activity in the acquisition phase, they were classified as sensitized (EtOH_High) or non-sensitized (EtOH_Low). After 18 h or 5 days, their brains were processed for FosB/DeltaFosB immunohistochemistry. On the 5th day of withdrawal, we could observe increased FosB/DeltaFosB expression in the EtOH_High group (in the motor cortex), in the EtOH_Low group (in the ventral tegmental area), and in both groups (in the striatum). Differences were more consistent in the EtOH_Low group. Therefore, behavioral variability observed in the acquisition phase of ethanol-induced locomotor sensitization was accompanied by differential neuronal plasticity during withdrawal period. Furthermore, distinct patterns of FosB/DeltaFosB expression detected in sensitized and non-sensitized mice seem to be more related to withdrawal period rather than to chronic drug exposure. Finally, increases in FosB/DeltaFosB expression during withdrawal period could be considered as being due to both functional and pathological plasticity.

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This paper aims to evaluate the anti-emetic efficacy of cannabinoids in cancer patients receiving chemotherapy using a systematic review of literature searched within electronic databases such as PUBMED, EMBASE, PSYCINFO, LILACS, and 'The Cochrane Collaboration Controlled Trials Register'. Studies chosen were randomized clinical trials comprising all publications of each database until December 2006. From 12 749 initially identified papers, 30 fulfilled the inclusion criteria for this review, with demonstration of superiority of the anti-emetic efficacy of cannabinoids compared with conventional drugs and placebo. The adverse effects were more intense and occurred more often among patients who used cannabinoids. Five meta-analyses were carried out: (1) dronabinol versus placebo [n=185; relative risk (RR)=0.47; confidence interval (CI)=0.19-1.16]; (2) Dronabinol versus neuroleptics [n=325; RR=0.67; CI=0.47-0.96; number needed to treat (NNT)=3.4]; (3) nabilone versus neuroleptics (n=277; RR=0.88; CI=0.72-1.08); (4) levonantradol versus neuroleptics (n=194; RR=0.94; CI=0.75-1.18); and (5) patients' preference for cannabis or other drugs (n=1138; RR=0.33; CI=0.24-0.44; NNT=1.8). The superiority of the anti-emetic efficacy of cannabinoids was demonstrated through meta-analysis.

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This study ensued from clinical observations based on spontaneous accounts by crack abusers undergoing their first psychiatric assessment, where they reported using cannabis in an attempt to ease their own withdrawal symptoms. Throughout a period of nine months, the researchers followed up on 25 male patients aged 16 to 28 who were strongly addicted to crack, as diagnosed through the Composite International Diagnostic Interview (CIDI), according to CID-10 and DSM-IV diagnostic criteria. Most of the subjects (68%, or 17 individuals) ceased to use crack and reported that the use of cannabis had reduced their craving symptoms, and produced subjective and concrete changes in their behavior, helping them to overcome crack addiction. The authors discuss some psychological, pharmacological and cultural aspects of these findings.

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Nos últimos anos tem sido observado aumento do uso de crack (uma forma de cocaína fumada) em pesquisas epidemiológicas e em apreensoes policiais. Até o presente, nao havia dados brasileiros relacionando a procura de tratamento para a dependência de cocaína com as vias habituais de administraçao. Objetivo. Analisar as modificaçoes das vias de administraçao da cocaína em uma populaçao de 245 pacientes atendidos em dois serviços ambulatoriais especializados (PROAD e UDED), na cidade de Sao Paulo, entre os anos de 1990 e 1993. Métodos. Dados de entrevistas padronizadas realizadas na admissao dos pacientes aos serviços foram estudados e determinada a prevalência de uso das diferentes vias de administraçao de cocaína. Resultados. A percentagem de pacientes que relataram uso de cocaína fumada (crack) aumentou de 17 por cento, em 1990, para 64 por cento em 1993 (p<0,01). O uso de cocaína aspirada nao variou durante esse período, permanecendo a via mais freqüentemente relatada (80 por cento), enquanto a via endovenosa variou de 40 por cento, em 1990, para 18 por cento, em 1992, e para 28 por cento, em 1993. Conclusoes. As implicaçoes do aumento de usuários de crack que procuram tratamento sao discutidas em funçao do planejamento de tratamento e de programas de prevençao, com ênfase no risco de transmissao do vírus HIV.

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Unsubstantiated reports suggest that the availability and use of crack are increasing in São Paulo. To investigate this claim we used the databases from two outpatient clinics for drug users at a public hospital and examined the changes in the reported routes of administration of cocaine among 245 patients who had attended between 1990 and 1993. The proportion reporting crack use increased from 17% in 1990 to 64% in 1993 (p < .01). It does not seem that this increase was simply due to changes in demographic variables. Treatment policies need to be reviewed and HIV harm-reduction programs should focus more on the risks of sexual transmission.

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