Khat Use Is Associated with Impaired Working Memory and Cognitive Flexibility

Rationale Khat consumption has increased during the last decades in Eastern Africa and has become a global phenomenon spreading to ethnic communities in the rest of the world, such as The Netherlands, United Kingdom, Canada, and the United States. Very little is known, however, about the relation between khat use and cognitive control functions in khat users. Objective We studied whether khat use is associated with changes in working memory (WM) and cognitive flexibility, two central cognitive control functions. Methods Khat users and khat-free controls were matched in terms of sex, ethnicity, age, alcohol and cannabis consumption, and IQ (Raven's progressive matrices). Groups were tested on cognitive flexibility, as measured by a Global-Local task, and on WM using an N-back task. Result Khat users performed significantly worse than controls on tasks tapping into cognitive flexibility as well as monitoring of information in WM. Conclusions The present findings suggest that khat use impairs both cognitive flexibility and the updating of information in WM. The inability to monitor information in WM and to adjust behavior rapidly and flexibly may have repercussions for daily life activities

Effects of alcohol preload on attentional bias towards cocaine-related cues

Background Drug and alcohol users have an ‘attentional bias’ for substance-related cues, which is likely to reflect the incentive-motivational properties of those cues. Furthermore, administration of an alcohol preload increases attentional bias for alcohol and tobacco-related cues in heavy drinkers and tobacco smokers, respectively. The present study investigated attentional bias for cocaine cues in cocaine users and non-users following administration of either alcohol or placebo. Method Thirty-two regular cocaine users and 40 non-users took part. Participants were administered alcohol or placebo, and administration was double blind. After drink administration, a Visual Probe task and Modified Stroop task were used to assess attentional bias. Subjective craving and alcohol outcome expectancies were also measured. Results There was a significant interaction between group and drink type on the visual probe task indicating that cocaine users who had received alcohol had increased attentional bias for cocaine pictures compared to non-users and cocaine users who received placebo. The cocaine Stroop revealed no differences between cocaine users and non-users, and no effects of alcohol in either group. Conclusions Alcohol preload in regular cocaine users increases attentional bias for cocaine cues. However, cocaine users who received placebo did not show attentional bias for cocaine stimuli. Future research should investigate the effects of alcohol preload on attentional bias in cocaine-dependent individuals

Lichamelijke gevolgen van druggebruik

Overmatig gebruik van alcohol, tabak en drugs veroorzaakt op termijn lichamelijke gezondheidsschade. Roken verhoogt het risico op longkanker en overmatig alcoholgebruik is geassocieerd met levercirrose en tumoren in de mondholte, slokdarm en de lever. De medische behandeling daarvan brengt kosten met zich mee. Ten opzichte van drugsgebruik zijn de gezondheidsschade en de behandelingskosten van overmatig alcohol- en tabakgebruik hoger. Dat komt vooral doordat relatief veel mensen roken (27 procent van de Nederlandse bevolking) of overmatig alcohol gebruiken (84 procent drinkt, waarvan 10 procent overmatig). Drugs worden daarentegen door relatief weinig mensen (recent gebruik is 0,1 tot 4,2 procent) en meestal gedurende enkele jaren gebruikt. Op individueel niveau is de lichamelijke gezondheidsschade van overmatig alcohol- en tabakgebruik vergelijkbaar met die van recreatief gebruik van de harddrugs heroïne en crack. In het algemeen leidt alleen intensief gebruik van drugs en genotmiddelen tot grote lichamelijke gezondheidsschade. Lichamelijke gevolgen van drugs zijn beperkt Deze conclusie blijkt uit een literatuuronderzoek van het RIVM. Hierin wordt een overzicht gegeven van de lichamelijke gezondheidsschade van zeventien recreatieve drugs, alcohol en tabak. Het onderzoek is uitgevoerd in opdracht van ZonMw, dat ook onderzoek heeft laten doen naar de psychische, verslavende en sociale effecten van drugs. Deze gevolgen zijn waarschijnlijk vaak groter dan de lichamelijke gezondheidsschade. Lichamelijke gevolgen van de vier meest gebruikte drugs Van de vier meest gebruikte drugs, cocaïne, cannabis, amfetamine en ecstasy, lijkt het gebruik van ecstasy niet te leiden tot ernstige lichamelijke gezondheidsschade. Het roken van cannabis is positief geassocieerd met longkanker en COPD. Het gebruik van heroïne, cocaïne en crack kan leiden tot infectieziekten, AIDS en tuberculose; het gebruik van vuile naalden veroorzaakt hierbij de meeste problemen. Cocaïne-, crack- en (herhaald) amfetaminegebruik is gerelateerd aan hart- en vaatziekten. Van alle drugs is kans op een (fatale) hartaanval het grootst bij het snuiven van cocaïne. Ook het gebruik van khat en anabole steroïden wordt in verband gebracht met hart- en vaatziekten, maar het bewijs hiervoor is vrij zwak. Urologische complicaties door regelmatig gebruik van het narcosemiddel ketamine worden in de literatuur gemeld, maar ze komen weinig voor. Orale kankervormen kunnen ontstaan door intensief khatgebruik. Tot slot hebben vrijwel alle problematische gebruikers van harddrug tandheelkundige aandoeningen. Voor de meeste drugs is het moeilijk om aan te geven wat het verband is tussen het gebruik en de ziekten die daaruit voortvloeien. De drugs worden namelijk vaak in combinatie met andere drugs, en met tabak en alcohol gebruikt (polydrugsgebruik). Vooral de mate waarin en wijze waarop de middelen in het verleden zijn gebruikt, is nauwelijks bekend. Deze kennis is nodig om een verband te kunnen leggen tussen ziekten en het gebruik van de verschillende genotsmiddelen.Excessive use of alcohol, tobacco and illicit drugs cause long term physical health damage. Smoking can cause lung cancer, and alcohol abuse may lead to liver cirrhosis and tumors in the oral cavity, esophagus and liver. The medical treatment of the diseases leads to financial costs. The health effects and treatment of alcohol and tobacco use are higher as compared to those of illicit drugs use. This is mainly due to the relatively large number of people smoking (27 percent of the Dutch population) or excessive alcohol use (84 percent drink, of which 10 percent drink excessive). Illicit drugs are, however, used by relatively few people (recent use is 0.1 to 4.2 percent) and mostly used for only some years. At the individual level, the physical health effects of alcohol and tobacco use are similar to those of recreational use of hard drugs heroin and crack. In general, only the intensive use of illicit drugs i.e. the abuse of drugs leads to great physical health damage. Physical effects of drugs are limited This emerged from a literature review of the RIVM, which gives an overview of the physical health damage of seventeen recreational drugs, alcohol and tobacco. The study was commissioned by ZonMw, that has also initiated research to the psychological and social effects of illicit drugs. The latter consequences are often greater than the physical health damage. Physical effects of the four most commonly used drugs Of the four most commonly used illicit drugs, like ecstasy, cocaine, cannabis, amphetamine, ecstasy seems not to lead to serious physical health damage. Cannabis smoking can cause lung cancer and COPD. The use of heroin, cocaine and crack can cause infectious diseases, AIDS and tuberculosis; the use of dirty needles caused the most problems here. Cocaine, crack and (repeated) amphetamine use is related to heart disease. Of all illicit drugs, risk of (fatal) heart attack is greatest when snorting cocaine. The use of khat and anabolic steroids is associated with cardiovascular disease, but the evidence is fairly weak. Urological complications by regular use of the anesthetic ketamine are reported in the literature, but they are rare. Oral cancers can be caused by intensive use khat. Finally, almost all the problematic hard drug users suffer from dental disease. For most illicit drugs, it is difficult to indicate the association between the use and the diseases caused by them, because the drugs are frequently combined with other drugs, tobacco and alcohol (poly drug use). In particular, the extent to which and how the illicit drugs are used in the past, is hardly known. This knowledge is necessary to link disease to the use of various drugs.ZonM