Does the ‘gateway’ matter? Associations between the order of drug use initiation and the development of drug dependence in the National Comorbidity Study Replication

Abstract

Background-The 'gateway' pattern of drug initiation describes a normative sequence, beginning with alcohol and tobacco use, followed by cannabis, then other illicit drugs. Previous work has suggested that 'violations' of this sequence may be predictors of later problems but other determinants were not considered. We have examined the role of pre-existing mental disorders and sociodemographics in explaining the predictive effects of violations using data from the US National Comorbidity Survey Replication (NCS-R).

Tobacco, Cannabis, and Other Illicit Drug Use Among Finnish Adolescent Twins: Causal Relationship or Correlated Liabilities?

“…These gateway theories for tobacco, and particularly for cannabis use, have been a source of recent and lively debate (e.g., Anthony, 2002;Kandel et al, 2006;Kenkel and Mathios, 2002;Lynskey, 2002;Maccoun, 2006). Although most researchers emphasize the co-occurrence of use of various substances and agree with the normative se-quence (Degenhardt et al, 2009)-beginning with licit drugs, such as alcohol and tobacco, followed by cannabis, then other illicit drugs-they differ in respect to how these phenomena can be explained. As a plausible alternative to the gateway theory, a common factor model, has been postulated (Morral et al, 2002), which may, for instance be refl ected in an individual's propensity to associate with others who use drugs (Lynksey et al, 1998), or by a common genetic vulnerability underlying any substance use (Lynskey, 2002).…”

Impulsivity, Sensation Seeking and Anhedonia as Possible Explanations for Cannabis Abuse Comorbidity among First Psychotic Episode Inpatients

“…However, despite the significant prevalence of substance use disorders in schizophrenia and its clinical implications, little is known about why these two disorders are so predominantly comorbid. This phenomenon has sparked extensive research into the nature of the relationship [2,3] and the resolution of this connection is more difficult than it would seem. It is hard to distinguish between the cause and the effect of the comorbidity owing to such methodological issues as the ascertainment and sampling of study populations, the setting of criteria regarding questionable clinical severity, and the use of varying diagnostic standards [4].…”

Stimulant use disorders and psychosis: prevalence, correlates and impacts

“…Cannabis use not only accompanies stimulant use, it typically precedes it, in a so-called "gateway" pattern (Degenhardt et al, 2009a). In the US National Comorbidity Study…”

“…Replication, more than 96% of drug users used cannabis before using other illicit drugs (Degenhardt et al, 2009a). The second Australian national survey of psychosis found that more than 98% of people with psychosis who used stimulants had previously used cannabis (Power et al, 2014).…”

“…Rates of stimulant use may also be influenced by the subtype or stage of psychosis; several studies of people with a first episode of schizophrenia-spectrum or affective psychosis have reported rates of stimulant use or dependence between 15% and 30% (Hides et al, 2006;Mauri et al, 2006;Rabinowitz et al, 1998;Ruiz-Veguilla et al, 2009;Sara et al, 2013;Wade et al, 2005). Cannabis use often precedes or accompanies stimulant use (Degenhardt et al, 2009a;Power et al, 2014) and cannabis disorders are one of the strongest predictors of later stimulant disorder (Degenhardt et al, 2007c). Therefore in examining stimulant use disorders it is also important to measure and control for cannabis use disorders.…”