Methamphetamine use and acquisitive crime: Evidence of a relationship

Methamphetamine is a drug of concern in Australia, with availability and purity on the rise (ACC 2014). The Australian Criminal Intelligence Commission (ACIC; formerly Australian Crime Commission; ACC) has identified methamphetamine as presenting a risk to the Australian community in a number of ways, including through its link with engagement in property crime (2015). Recent data from the Drug Use Monitoring in Australia (DUMA) program indicates methamphetamine use among police detainees has risen 23 percentage points, from 14 percent in 2009 to 37 percent in 2014 (Goldsmid & Brown 2015). If methamphetamine use is associated with an increased likelihood of engagement in property crimes, as the ACIC suggests, then a commensurate rise in property crime—at least among offender populations—can be anticipated. Identifying the factors and motivations that lead to methamphetamine-driven offending could assist law enforcement and government to predict and combat future crime trends.

There is substantial empirical evidence of an association between illicit drug use and offending (Makkai 2003; Bennett & Holloway 2005; Best, Sidwell, Gossop, Harris & Strang 2001). Specifically, methamphetamine use has been associated with an increased risk of engagement in violent (Darke et al. 2009; Brecht & Herbeck 2013) and property offences (Gizzi & Gerkin 2010), although not all illicit drug users engage in crime (Morgan 2014). The current study aims to explore the relationship between methamphetamine use and offending, with a focus on offender populations as represented by people in police detention at the time of interview.

Reliance on unconventional and illegal income

The economic model of crime suggests the likelihood of engaging in crime, especially property crime, increases with the increased frequency of substance abuse or addiction (White & Gorman 2000), probably due to the need for income to support illicit drug purchases. If this is the case, it could be expected that methamphetamine users would report a greater reliance on unconventional and illegal sources of income than non-users.

Wilkins and Sweetsur (2010) provide some support for this assertion, reporting that the level of spending on amphetamines by a sample of New Zealand police detainees was positively associated with their reported earnings from property crime and drug dealing (examined separately)—that is, greater income from property crime and drug dealing corresponded with greater spending on amphetamines. Furthermore, an Australian study of police detainees found a higher rate of property offences was recorded for heavy amphetamine users at the time of arrest, compared with non-users and moderate users (Bradford & Payne 2012).

Polydrug use

Polydrug use is the concurrent or sequential use of multiple psychoactive substances (Wilkinson et al. 1987). Based on data derived from the English and Welsh Arrestee Drug Abuse Monitoring program, Bennett and Holloway (2005) reported the mean number of acquisitive offences reported by a detainee was positively associated with the number of different drug types the detainee had consumed in the past year. Polydrug users who used heroin, crack and cocaine and many other drug types had higher offending rates than heroin, crack and cocaine users who used fewer other drugs (Bennett & Holloway 2005). With high rates of polydrug use among methamphetamine users (Pennell, Ellett, Rienick & Grimes 1999; Gately et al 2012), it is important to tease out whether it is the use of a specific substance such as methamphetamine, or the combined use of multiple substances—perhaps as a marker of overall engagement with the illicit drug market—that is associated with engagement in acquisitive crime in a sample of Australian offenders.

Causal nature of use/offending association

Four models have been proposed to explain drug use and offending associations. These are:

• the ‘drug-crime’ model (where use of illicit drugs leads to engagement in crime to fund further illicit drug use);
• the ‘crime-drug’ model (where criminal activity leads to engagement in illicit drug use);
• the ‘common-cause’ model (where crime and drug use are not directly associated but instead related through a common sociological or psychological cause, such as delinquency or age); and
• the ‘coincidence model’, which argues there is no causal association between drug use and crime (White & Gorman 2000).

Determining the exact causal nature of the association is complex, and the problem remains unresolved within criminological literature. To add to this complexity, not all illicit drug users engage in criminal offending; of those who do, some are drug users prior to offending and some are offenders prior to becoming illicit drug users (Morgan 2014).

In the absence of a comprehensive longitudinal study, understanding how offenders perceive the part illicit drug use plays in their offending may provide insight into its role as a motivating factor. Restricting this investigation to methamphetamine-using offenders and examining their motivations for offending across crime types allowed the study to determine whether motivations for acquisitive offending are unique to individual offenders or, rather, common to all offenders who use methamphetamine.

Examinations that have adopted a similar approach have identified that offending among methamphetamine users appears to be primarily motivated by financial need. For example, Gizzi & Gerkin (2010) reported 28 percent of crimes committed by regular methamphetamine users were described by those users as committed to financially support their use of methamphetamine. In addition, intoxication appears to be a factor in offending. A 2013 study of a sample of Australian injecting drug users reported 24 percent of those who committed property offences were under the influence of methamphetamine at the time of offending (Sutherland, Sindicich & Burns 2014). It is therefore of interest to examine whether methamphetamine users detained for violent, property and/or drug offences report their crimes were motivated by financial need and/or intoxication.

Current study

The current study aimed to:

• compare the proportion of income derived from crime by police detainees who use methamphetamine with that of those who do not;
• examine whether polydrug use and the use of specific licit and illicit substances is associated with engagement in acquisitive crime by a sample of police detainees; and
• examine, across crime types, the motivations for offending of police detainees who use methamphetamine.

Method

The data presented in this study are derived from the Drug Use Monitoring in Australia (DUMA) program (Makkai 1999). Every quarter, the DUMA program conducts interviews with police detainees, at selected police stations and watch houses across Australia, about their drug use and criminal offending. In 2013, data was collected in Perth, Adelaide and Brisbane and at two Sydney sites, Kings Cross and Bankstown. All police detainees present at a participating watch house during data collection were eligible to participate, with the exclusion of those who had been in custody for more than 96 hours (and who therefore had not had recent contact with the drug market) and those who were unfit for interview due to a high level of intoxication, mental illness or violent or aggressive tendencies. Interviews took place over a four-week period at each site. For further details on interviewee recruitment procedures, refer to Makkai (1999).

Procedures for gaining access to detainees vary between jurisdictions, but generally involve police introducing detainees to DUMA interviewers. DUMA interviewers identify themselves as representatives of the research project and independent of police, and advise detainees their participation will be anonymous and confidential. If a detainee consents to participate, an interview is conducted at the police station or watch house, in a private room where the information they provide cannot be overheard by police.

A total of 1,146 police detainees were interviewed for the DUMA program in quarters 3 and 4 of 2013. Of these, 35.8 percent of detainees (n=410) reported using methamphetamine in the 30 days prior to their detention by police. This is a sufficiently large sample to allow comparison between detainees who used methamphetamine and those who did not. The 736 detainees who reported they had not used methamphetamine in the previous 30 days were labelled as non-users for the purpose of this examination; only 390 detainees reported no use of any illicit drug in the previous 30 days.

Measures

Demographic variables

Respondents were asked to provide basic demographic information including gender, age and Indigenous status.

Alcohol and illicit drug use

Respondents were asked on how many of the previous 30 days they had used methamphetamine/speed/ice, alcohol, cannabis, heroin or ecstasy. Responses were recoded so that any number of days of use was coded to the affirmative (1) and no days of use as an absence of use in the previous 30 days (0). Respondents were also asked whether they had used cocaine and inhalants in the previous 30 days. Responses to these items were coded as use in the past 30 days (1) or an absence of use in the past 30 days (0).

Income from crime

Income from crime was measured via two self-report items. The first asked respondents how much of their income in the previous 30 days came from crime. Possible responses were:

• all of it (1);
• most of it (2);
• about half of it (3);
• some of it (4); and
• none of it (5).

The second item asked how the respondent obtained income or supported themselves in the previous 30 days. Respondents could choose more than one response. Available responses were from:

• family or friends (1);
• welfare or government benefits (2);
• full-time work (3);
• part-time work (4);
• other income (such as superannuation or savings; 5);
• sex work (6);
• shoplifting (7);
• drug dealing or other drug crime (8); and
• other crime (such as theft, fraud, burglary and robbery; 9).

Criminal offending

The charge(s) for which the detainee was being held in police custody at the time of interview was recorded for each respondent. Based on the Australian Bureau of Statistics (ABS) Australian and New Zealand Standard Offence Classification (ANZSOC) scheme, each charge was coded into one of eight categories, which included:

• violent offences;
• property offences;
• drug offences;
• traffic offences (including drink-driving);
• breaches; and
• other lesser offences.

Respondents were then classified based on the most serious charge for which they were being detained at the time of interview.

Perceived role of substance use in offending

Respondents were asked to what extent they thought methamphetamine/speed/ice had contributed to the incident that led to their detention. Response alternatives were:

• not at all (1);
• a little (2);
• a lot (3); and
• don’t know (9).

If the response indicated the detainee believed methamphetamine/speed/ice had played a part in their current offending, they were asked to describe its role. Respondents could select one or more of the following responses:

• they needed money to buy methamphetamine/speed/ice;
• they were high on methamphetamine/speed/ice at the time of the offence;
• they were ‘hanging out’ for methamphetamine/speed/ice; or
• there was some other reason related to the use of these drugs.

Respondents who selected the final option were requested to specify this other reason.

Results

Profile of methamphetamine-using detainees

There were 206 women (18%) and 944 men (82%) in the sample. The over-representation of men in the sample is representative of the gender distribution of the general Australian police detainee population from which the sample was taken. The average age of detainees was 31.45 years (SD=10.11). Table 1 shows the demographic characteristics, sources of income, and alcohol and other drug use of methamphetamine users and non-users.

When comparing detainees who reported the use of methamphetamine in the previous 30 days with those who did not, there were no significant differences in terms of gender or age. However, a higher proportion of methamphetamine users in detention were Indigenous than non-Indigenous.

Methamphetamine users were more likely than non-users to report using cannabis, heroin, ecstasy and/or cocaine in the 30 days prior to interview (see Table 1). There were no significant differences between users and non-users in the use of alcohol or inhalants.

Source: AIC Drug Use Monitoring in Australia 2013 [computer file]

a: Includes cannabis, heroin, methamphetamine, ecstasy, cocaine, LSD and inhalants

Income

Proportion of income from crime

The study used the proportion of income detainees reported having sourced from crime to compare how methamphetamine-using detainees and those who did not use methamphetamine engaged in crime to generate an income. Detainees who had used methamphetamine in the previous 30 days (M=4.35, SD=1.14) reported sourcing a significantly higher proportion of their income from crime in over the same period than did non-users ([M=4.87, SD=0.56], t[1115]=10.18, p<0.001).

Income from legal and illegal activity

Table 1 lists the sources of income reported by methamphetamine users and non-users (detainees could nominate multiple income sources). A greater proportion of methamphetamine users than non-users reported obtaining income from family and friends, welfare, sex work, shoplifting, drug dealing and drug-related crime, and other crime. A higher proportion of those who did not use methamphetamine reported an income from full-time employment than did methamphetamine users.

Criminal offending

Acquisitive crime

An acquisitive crime variable was created to represent whether a detainee reported receiving an income from shoplifting, drug dealing and other crime in the previous 30 days (1) or from none of these sources (0). A logistic regression analysis was then conducted to examine whether polydrug use or the use of a particular illicit drug was associated with obtaining an income from acquisitive crime in the previous 30 days while controlling for the use of other illicit substances (see Table 2). The model was significant: methamphetamine, heroin and cannabis use were significantly associated with engaging in acquisitive crime, after controlling for other drug use. The likelihood of a methamphetamine user reporting income from acquisitive crime was approximately four and a half times higher than of a non-user doing so; the likelihood of a heroin user reporting income from acquisitive crime was approximately four times higher than that of a non-user; and the likelihood of a cannabis user reporting income from acquisitive crime was almost two times higher than that of a non-user.

Current offence classification

To further examine differences in the offending patterns of methamphetamine users and non-users, detainees were classified by the most serious offence for which they were detained at the time of interview. Table 3 shows the proportion of methamphetamine users and non-users in each of the most serious offence classifications.

Methamphetamine users were significantly more likely than non-users to be classified by most serious offence as a property or drug offender. Non-users were more likely than methamphetamine users to be classified as traffic or disorder offenders. There were no statistically significant differences between the proportion of methamphetamine users and non-users classified as violent or breach offenders.

Source: AIC Drug Use Monitoring in Australia 2013 [computer file]

Note: χ²(6)=146.82, p<0.001; percent of correct predictions 84.73%; AUC=0.76; Pseudo R2=0.15

a: Includes cannabis, heroin, methamphetamine, ecstasy, cocaine, LSD and inhalants

Source: AIC Drug Use Monitoring in Australia 2013 [computer file]

Source: AIC Drug Use Monitoring in Australia 2013 [computer file]

Role of methamphetamine in offending

Methamphetamine-using detainees in custody for drug offences (64%) were more likely than other offender types to report methamphetamine had contributed a little or a lot to their current offending. It is likely many drug offenders recognised the role methamphetamine played in their current offending due to the drug-defined nature of the offence. High rates of attribution were also reported among violent offenders (58%), property offenders (50%) and breach offenders (44%).

If detainees indicated methamphetamine use had played a role in their current offending, they were asked to describe that role (see Table 4). Detainees could select multiple responses. Of the possible responses, detainees were most likely to describe the role of methamphetamine in their offending as related to intoxication (‘high on it’). The responses of those who selected ‘other’ (n=102) were grouped into the following broad categories:

• 58 referred to being held by police on methamphetamine-related drug charges;
• 30 related to being intoxicated;
• six related to peer-group influences;
• five referred to either ‘hanging out for’ (experiencing withdrawal symptoms) or ‘coming down from’ (the effects of the drug wearing off) methamphetamine,
• five referred to mental health issues related to drug use; and
• two referred to a need for money.

As it cannot be determined whether these comments duplicated responses already provided in the table, they have not been added to the relevant categories.

Discussion

This study provides further evidence of an association between methamphetamine use and criminal offending, particularly with property and drug-related crime. Both methamphetamine users and heroin users were approximately four times more likely than non-users to report obtaining income from acquisitive crime. These associations were maintained even when polydrug use and the use of other illicit drugs was controlled for. Methamphetamine users’ reports indicate intoxication and the need for money were the most common motivations for engaging in property crime. Drug-related crime was reported to be most commonly related to intoxication.

Cannabis users were almost twice as likely as non-users to report generating income from acquisitive crime. Given those detainees who reported no cannabis use also reported no use of any other illicit drug (including heroin, ecstasy, cocaine, inhalants and methamphetamine) in the previous 30 days, this could indicate that the use of illicit drugs almost doubles the likelihood of a police detainee engaging in acquisitive crime. This may be driven by the illicit drug use itself, or by the demographic and socioeconomic factors that increase the likelihood of both illicit drug use and offending.

Polydrug use

A higher proportion of methamphetamine users than non-users reported using cannabis, heroin, ecstasy and cocaine. In fact, rates of polydrug use among methamphetamine users were much higher than those of non-users. This may be indicative of the nature of methamphetamine use and the associated practice of counteracting the effects of methamphetamine withdrawal by consuming other substances; it may also be that detainees who use methamphetamines tend to be those whose characteristics and circumstances lead them towards higher overall levels of substance use. Further research into the socio-demographic characteristics, attitudes and life experiences of methamphetamine users could illuminate this possibility. Alternatively, it may be that illicit drug users whose drug of concern is something other than methamphetamine (eg heroin, cocaine or cannabis) may have used methamphetamine due to its ready availability.

Regardless of influencing factors, polydrug use is associated with a number of health concerns over and above those associated with consumption of individual substances. This health risk requires monitoring.

When controlling for use of individual illicit drugs, polydrug use was not significantly associated with engagement in acquisitive crime. This contradicts Bennett and Holloway’s (2005) finding that polydrug use is linked to a higher rate of acquisitive crime. Methodological differences between the studies may explain these contradictory findings. Bennett and Holloway examined the association between crime rates and the number of drug types consumed, whereas the current study utilised discrete variables of use versus non-use. Alternatively, it may be that geographical and temporal differences in the use and availability of methamphetamine may limit the comparability of Bennett and Holloways’ earlier England and Wales-based findings with the more recent Australian findings.

Causal nature of use/offending association

The behavioural and psychological consequences of intoxication were the most commonly cited ways in which detainees reported methamphetamine use influenced their offending, followed by the need for money to buy drugs. To the extent that this model best describes the perceived motivation for offending reported by methamphetamine users, the finding supports a drug/crime model, with the use of methamphetamine leading to intoxication and, consequently, to offending.

If methamphetamine influences offending via intoxication, it could be expected that methamphetamine users would commit a greater number of expressive crimes, such as violent and disorder offences, than do non-users. There was, however, no significant difference in the rates of violent and breach offence crimes committed by methamphetamine users and non-users, and methamphetamine users were less likely than non-users to be categorised as disorder offenders. It is possible that, for some users, the effects of methamphetamine intoxication are expressed through their behaviour when interacting with police rather than in the commission of their primary offence. For example, methamphetamine users arrested for property offences may react more aggressively during and after the arrest than non-users, without this behaviour constituting a violent offence. Further research into the experiences of police and other front-line services, and the attributions of methamphetamine-using offenders, could inform this issue.

Limitations

This study was limited in relying on retrospective, self-report data. Detainees may have under-reported their engagement in illegal activities to avoid implicating themselves in offending that had not yet come to the attention of police. However, the anonymous and confidential way in which the questionnaire was administered would have mitigated this risk to some extent, as would the structure of the items. It is unlikely that concerns about disclosure would have unduly influenced one group of illicit drug users more than another. Self-reports of illicit drug use in this study are also likely to be conservative estimates of the true extent of illicit drug use (Wish 1997).

Caution should be taken in generalising the findings to non-offending populations. Methamphetamine users involved in crime are likely to differ from those who are not in the frequency of their use and the purity of the substance they consume. A substantially greater proportion of police detainees have used methamphetamine than the general population (AIHW 2014), and detainees are more likely than those not involved in crime to have been in recent and regular contact with the drug market.

Finally, this study was cross-sectional and, as such, the findings can provide only limited insight into the causal relationship between methamphetamine use and offending.

Conclusion

In conclusion, the findings show that recent use of methamphetamine is an effective indicator of an increased risk of engaging in acquisitive crime. How methamphetamine use leads to offending remains unclear; however, methamphetamine users reported their offending is commonly precipitated by intoxication or motivated by the need for money. Recognising the impact of methamphetamine use on offending could assist police and government policymakers to proactively direct resources and implement strategies to combat any potential rise in offending which may be associated with a rise in the use of methamphetamine among offender populations.

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Matthew Willis is a Research Manager at the Australian Institute of Criminology.

Susan Goldsmid is a Principal Research Analyst at the Australian Institute of Criminology.