Addiction (1996) 91(1), 81-87

RESEARCH NOTE

Psychological morbidity and route ofadministration among amphetamine users inSydney, Australia

WAYNE HALL, JULIE HANDO, SHANE DARKE & JOANNE ROSS

National Drug and Alcohol Research Centre, New South Wales, Australia

AbstractA sample of 301 amphetamine users were interviewed about their experiences of psychological symptoms priorto, and subsequent to, their initiation of amphetamine use. Psychological morbidity was common, with 44%scoring greater than a conservative cut-off of 8 on the General Health Questionnaire. The most commonlyreported symptoms subsequent to the onset of amphetamine use were depression (79%), anxiety (76%),paranoia (52%), hallucinations (46%) and violent behaviour (44%). All these symptoms increased inprevalence after the onset of amphetamine use. Route and frequency of amphetamine administration weresignificant independent predictors of overall psychological morbidity, while route of administration was relatedto the experience of hallucinations, violent behaviour and paranoia. The avoidance of injection as a route ofadministration and the use of amphetamines less than weekly are recommended as steps that users can taketo reduce the psychological sequelae of amphetamine use.

Introduction dependence syndrome that is characterized by aThe increased prevalence of injecting am- prolonged withdrawal syndrome in which de-phetamine use among illicit drug users in Aus- pression, lethargy and irritability contribute to atralia during the late 1980s''^ has raised a high rate of relapse to use after abstinence;'*'' anumber of health concerns. First, injecting am- paranoid psychosis in which loosening of associ-phetamine users could transmit HIV and other ations, delusions and auditory hallucinations areinfectious diseases, such as hepatitis B and C, by the most common symptoms*"* and episodes ofneedle-sharing and unsafe sexual behaviour.^ extreme, apparently unmotivated violence.'Secondly, given experience in previous epi- In a previous study we examined the relation-demies of injecting amphetamine use, there was ship between these adverse outcomes of am-reason to expect that a substantial minority of phetamine use and injection as a method ofinjecting amphetamine users would develop administration.'" One-third of a sample of 231severe adverse psychological effects caused by amphetamine users reported symptoms of de-chronic heavy amphetamine use. These include a pendence on amphetamine which were associ-

Correspondence to: Professor Wayne Hall, National Drug and Alcohol Research Centre, University of New SouthWales, 2052, NSW, Australia.

0965-2140/96/010081-07 $8.00 © Society for the Study of Addiction to Alcohol and other Drugs

Carfax Publishing Company

82 Wayne Hall et al.

ated with the use of amphetamines two or moretimes per week, especially by injection. Therewere also high rates of symptoms of "paranoia"and "aggression" which were related to fre-quency of amphetamine use, route of adminis-tration, and to symptoms of dependence. Thepsychological symptoms, however, were assessedby dichotomous self-report items so it wasdifficult to assess their severity. It was not poss-ible, for example, to distinguish between transi-ent, relatively normal experiences of suspicionand paranoid ideation of psychotic intensity, orbetween brief episodes of anger and explosiveuncontrolled aggressive outbursts.

The aim of the current study was to replicateand extend the findings of previous research byexamining the relationship between route of ad-ministration and the prevalence and severity ofadverse effects of amphetamine use among am-phetamine users. In the current study more de-tailed questions were asked about psychologicalsymptoms presumptively related to am-phetamine use. These were: whether the symp-toms had occurred prior to amphetamine use,how long they lasted, whether they only occurredafter amphetamine use, and how disruptive andsevere each was.

MethodProcedureStructured face-to-face interviews were conduc-ted with 301 amphetamine users. All subjectswere volunteers who were paid A$20 for theirparticipation in the study. Recruitment tookplace from February to September of 1993, bymeans of advertisements placed in rockmagazines, local newspapers, needle exchanges,local coffee shops, by word of mouth and an-nouncements over a radio station. Only 5% ofsubjects were referred to the study through treat-ment centres. To be eligible subjects had to haveused amphetamines at least monthly for the pre-ceding 6 months and to live in the Sydney re-gion.

Interviews were conducted in a location deter-mined by the subject. Interview sites rangedfrom pubs, coffee shops, parks and shoppingcentres to peoples' homes and the researchers'work-place. Subjects were guaranteed, both atthe time of screening and interview, that anyinformation they provided would be kept strictly

confidential and anonymous. All interviews wereconducted by one of three interviewers and tookbetween 45 and 60 minutes.

MeasuresA structured interview was constructed that ex-amined demographics, drug use history, am-phetamine use history, transitions betweenroutes of amphetamine administration (seeDarke et a/.") and psychological symptoms.Current drug use was measured using the OpiateTreatment Index (OTI)'^ and global psychologi-cal functioning was assessed by the GeneralHealth Questionnaire (GHQ)'^. Subjects wereasked whether they had experienced any of anumber of psychological symptoms either beforeor after they had first used amphetamines.

The psychological symptoms included: anxi-ety, panic attacks, depression, attempted suicide,mania, violent behaviour, hallucinations andparanoia. Efforts were made to clearly describethe type of symptom that was being inquiredabout in each case (questionnaire available fromthe authors). For example, a panic attack wasenquired about as follows: "did you feel thatyour heart was pounding, that you were havingtrouble breathing, and were hyperventilating andyou were sweaty, shaky and frightened?". Para-noia was described as "feeling that people werespying on you, following you around, plottingagainst you or trying to hurt you"; hallucinationswere described as seeing or hearing "things thatother people around you couldn't see or hear";and manic behaviour was defined as experienc-ing "mood swings where you went straight fromfeeling depressed to feeling elated" and "yourthoughts raced, you couldn't keep still, youcouldn't sleep and you were easily distracted".

Subjects who reported that any of these symp-toms had occurred since having used am-phetamines were asked whether it had onlyoccurred while they were under the infiuence ofthe drug. They were also asked about the lengthof time each symptom lasted, and how severe thesymptom had been on a 5-point Likert scale(1 = not severe, 5 = extremely severe).

AnalysesA series of statistical analyses were performed toexamine the relationships between pattern ofamphetamine use and the risk of experiencing

Amphetamines and psychological morbidity 83

psychological symptoms. Multivariate analyseswere used to explore relationships betweensymptoms and patterns of amphetamine use,controlling for other characteristics that pre-dicted experience of these symptoms, includingreports of psychological symptoms precedingamphetamine use. Multiple linear regressionswere performed on an index of the severity ofpsychological symptoms, and multiple logisticregression analyses were performed on a smallnumber of categorical symptom outcomes (e.g.experienced hallucinations or not), using the ap-proach suggested by Hosmer & Lemeshow.'* Allanalyses were conducted using SYSTAT.'^

one-quarter (23%) reported use on 60 or moredays, and 13% on 90 or more days. -

Routes of amphetamine administrationTwo-thirds of the sample (67%) reported havinginjected amphetamine at some time during thepreceding 6 months. A quarter of the samplereported having both injected and snorted orswallowed amphetamines in the previous 6months, while 42% reported that injection hadbeen the sole method employed. The remainderof the sample (33%) had exclusively snorted orswallowed the drug.

ResultsSample characteristicsThe sample consisted of 301 subjects, of whom53% were male. The mean age was 25 years,with males being on average older than females(26 vs. 23 years, £299 = 5.1, p<0.001). Subjectswere recruited from all regions of Sydney. Themean number of years of school education was10.6, with 39% of subjects having completed 12years of schooling. The majority of subjects(64%) had no tertiary education, with 26% hav-ing completed a trade or technical course andonly 10% having acquired a university or collegedegree. Only 12% of subjects were in full-time,and 19% in part-time/casual employment. Mostsubjects (79%) were not currently in treatment,and two-thirds (68%) had never been in drugtreatment. Methadone maintenance was themost common form of therapy for those cur-rently in treatment (73%).

Other drug usePolydrug use was common: the median numberof drug types ever used was eight (range 4-10drug types), with a median of six drug classesused in the last 6 months (range 3-10 drugclasses). The use of cannabis (100% ever usedand 93% used in the last 6 months), alcohol(99% ever used and 94% in the last 6 months)and tobacco (97% ever used and 92% in the last6 months) was almost universal. The use ofhallucinogens, benzodiazepines, opiates and co-caine were also very common, with 95%, 74%,68% and 66%, respectively, having used them.Just over half (56%) the sample had injectedopiates, 51% in the last 6 months with a medianfrequency of once a week. The median numberof drug classes ever injected was 3 (range 1-6drug classes), and median number of drugclasses injected in the last 6 months was 2 (range1-6 drug classes injected).

Amphetamine useThe mean age of first amphetamine use was 17.4years (SD 4.0; median 17 years, range 12-59years) and the median age for the commence-ment of regular use was 18.0 years (range 10-59years). The median length of time since firstamphetamine use was 5 years (range 0-27years).

The median number of days on which am-phetamines were used in the 6 months prior tointerview was 24 (range 6-180 days), which cor-responds to approximately weekly use. Less than10% of subjects (9%) had used amphetamines 6times or less in the preceding 6 months, while

Psychological adjustmentThe mean GHQ score for the sample was 8 (SD6.9; range 0 = n28). Two thirds (67%) obtainedGHQ scores of 4 or greater (the usual cut-off forpsychological "caseness"). Just under half (44%)obtained scores of 8 or greater, a more conserva-tive cut-off that was used in our previous studyto take account of the fact that many of theafter-effects of amphetamine use are difficult todistinguish from the symptoms of minor psycho-logical morbidity assessed by the GHQ.

Adverse psychological symptomsThe symptoms of depression, anxiety, paranoia

84 Wayne Hall et al.

*p<0.05.

Table 1. Psychological symptoms among regular amphetamine users

Symptom

AnxietyPanic'DepressionSuicideManiaViolenceHallucinationParanoia

Before tstuse (%)

48It6223253913t9

After 1stuse (%)

7633792250444652

After speeduse episode (%)

4858583748356t59

Duration ofsymptom

24 hours1-2 hours2-3 days

—t-2 days

—30-60 minutes

t-2 hours

Severityof symptom

3.33.43,2—3.03.09t.6*3.0

McNemarchi-'square

64.4*5t.6*25.5*o.ot50.5*4,0*

89.3*

and mania were reported by half or more of thesample (Table 1). With the exception of suicideattempts, the prevalence of which remained low,all symptoms were reported at a higher rate afterthe person first used amphetamines (as assessedby McNemar chi-square tests). In the case ofanxiety and depression the rates of symptomsbefore amphetamine use were substantial, as onewould expect for non-specific symptoms of psy-chological distress. The mean severity ratings ofthose who experienced each symptom after usingamphetamine were 3 or greater on a 4-pointscale, with approximately half reporting"extremely" high levels of anxiety (48%), panic(55%) and depression (47%).

The duration of the symptoms and their per-ceived relationship to amphetamine use varied inpredictable ways (see Table 1). Hallucinationslasted for 30-60 minutes on average (corre-sponding to the duration of acute drug effects),with 40% experiencing auditory hallucinations,11% visual hallucinations and 46% experiencingboth auditory and visual hallucinations. Symp-toms of panic and paranoia typically lasted 1-2hours, although in 20% of cases symptoms ofparanoia was reported as lasting for 2 or moredays. Symptoms of anxiety, depression and ma-nia typically lasted for 1-2 days, probably as partof the "come-down" after heavy use. In the caseof anxiety (48%), panic (58%), depression(58%), mania (48%), hallucinations (61%) andparanoia (59%), half or more of the respondentsreported that the symptoms mainly occurred af-ter using amphetamine. In the case of violenceand attempted suicide, only one-third of thosewho experienced the symptom reported that theyoccurred after amphetamine use.

A principal components analysis (PCA) of the

ratings of the severity of each of the symptoms(excluding attempted suicide) indicated that thefirst PCA accounted for 42% of the variance,and all symptoms had loadings of greater than0.40 on this factor. A simple sum of the averageseverity ratings of each symptom (with zero forthose who did not report the symptom) pro-duced an index of the severity of psychologicalsjmiptoms which was used in subsequent multi-variate analyses of the correlates of psychologicalsymptoms.

Predictors of adverse psychological symptomsOverall symptom severity. Univariate analyses

indicated that the symptom severity index wasinversely related to education, and positively re-lated to a history of polydrug use, the frequencyof amphetamine use in the past 6 months, inject-ing as the usual route of administration, and thenumber of psychological symptoms reportedprior to initiating amphetamine use. When allthese variables were entered into a multiple lin-ear multiple regression analysis (see Table 2) asimpler model emerged in which only a smallnumber of variables predicted overall psychologi-cal morbidity. These were: a history of psycho-logical symptoms prior to amphetamine use (1.7units for each symptom experienced prior toinitiating amphetamine use), injection as theusual route of administration (2.0 units higher ininjectors), and frequency of amphetamine use inthe past 6 months (means of 9.1, 9.5, 10.9 and11.6 for each quartile of frequency of use,namely, less than 14 times, 14-24 times, 24-48times and greater than 48 times). Polydrug usedid not independently predict the severity of

Amphetamines and psychological morbidity 85

Table 2. Multivariate predictors of the index of severity ofpsychological symptoms

Variable Beta t

Usual route t,88 2,8t <0,001Frequency 0,9t 3,06 < 0,001

Prior symptoms (M) t,67 8,24 <0,001

R^ = 0.26 F(3,294) = 33.57.Usual route: t = swallowing or snorting; 2 = injecting

half ormore ofthe time; frequency: 1 = less than 14 days;2 = 14 to 24 days; 3 = 24 to 48 days; 4 = more than 48days in the last six months; prior symptoms = number ofpsychological symptoms experienced prior to am-phetamine use; Beta = unstandardised beta weight.

symptom index when included with these othervariables in the multiple regression analysis.

Specific psychological symptoms. Three specificpsychological symptoms that are most character-istic of severe psychological disturbance (halluci-nations, violent behaviour and paranoia) wereseparately analysed by multiple logistic re-gression. As expected, reports of all three symp-toms after beginning amphetamine use werestrongly associated with a history of having ex-perienced each prior to amphetamine use. Multi-variate logistic regression analyses indicated that,in addition, all three symptoms were predictedby injection as the usual route of administration:hallucinations (odds ratio (OR) = 2.14 [95%confidence interval (CI): 1.29, 3.55]); violentbehaviour (OR =2.20 [95% CI: 1.27, 3.80]);and paranoia (OR= 1.80 [95% CI: 1.08, 2.96]).

DiscussionThe main findings of the study were: that therewas a high prevalence of psychological morbidityamong a sample of amphetamine users; that theprevalence of most psychological symptoms re-portedly increased after the initiation of am-phetamine use; and that the severity of thesesymptoms was related to the frequency of am-phetamine use and injection as the usual route ofadministration. Just under half the sample (44%)showed psychological morbidity suggestive of apsychiatric diagnosis using a stringent GHQ cut-off of 8. These results confirm our earlier findingthat a transition to injecting is correlated withserious psychological symptoms in amphetamineusers.

These findings presuppose that the self-reported data on drug use and psychologicalsymptoms are valid. How reasonable is this pre-sumption? Research on illicit opiafe users hasshown that self-reported drug use can be reason-ably reliable and valid when users are givencredible assurances, that their anonymity will beprotected and that any information they supplywill be kept in the strictest confidence.'^"'^''^ Inthe present study, as in our previous study,efforts were made to establish rapport withusers, and to provide credible assurances ofconfidentiality to encourage honest disclosure ofdrug use and other socially stigmatised behav-iour.

In terms of the validity of the self-reportedpsychological symptoms, special efforts weremade to clarify the meaning of each of the symp-toms for interviewees, as explained above. Thereis necessarily less confidence in the validity of theretrospective assessments of whether psychologi-cal symptoms had been experienced prior toamphetamine use, which may have been as longas 6 years before interview. There was someconcurrent support for the validity of thesesymptoms: the reports of depressive and anxietysymptoms were more highly correlated with thetotal GHQ score (correlations of 0.25 and 0.32,respectively) than were reports of these symp-toms prior to amphetamine use (correlations of0.17 in both cases). The validity of the set ofpsychological symptoms was additionally sup-ported by the PCA results, which indicated sub-stantial degree of unidimensionality, and by thefinding that the symptoms score was correlatedwith the route and frequency of amphetamineuse, findings that would be unlikely to occur ifthe symptoms were unreliably measured.

Our confidence in the validity of the psycho-logical symptom data is enhanced by the factthat our present findings have broadly replicatedthose in our earlier study' which used crudermethods of assessment, in that there was a highprevalence of psychological morbidity amongamphetamine users that was related to the fre-quency of use and the usual route of administra-tion. Our results also support the clinicalobservations of the high prevalence of suchsymptoms among heavy injecting amphetamineusers in the late 1960s and early 1970s.''"'

We may seem to be going beyond the data inconcluding that the pattern of injecting am-phetamine use is a cause of the psychological

86 Wayne Hall et al.

symptoms, since our data is cross-sectional andretrospective self-report data. Can we excludethe possibility that the relationships we observedwere not due to other factors, such as polydruguse, and the possibility that more psychologicallytroubled individuals are more likely to becomeheavily involved in injecting amphetamine use?

The findings of both the present study and ourprevious study'" indicate that the relationshipbetween amphetamine use and psychologicalsymptoms is unlikely to be due to polydmg use.Although polydmg use was common in bothsafhples and its extent was correlated with psy-chological symptom severity in univariate analy-ses, the multiple regression analyses in bothstudies indicated that the relationship betweenpsychological symptoms and the route and fre-quency of amphetamine use was independent of,and hence not explained by, polydrug use.

It was also unlikely that the relationshipbetween psychological symptoms andamphetamine use can be explained by thehypothesis that troubled individuals are morelikely to take up this pattern of amphetamineuse. A history of prior psychological symptomswas related to the reported experience of symp-toms since commencing amphetamine use, asone would expect. However, a prior history ofsymptoms did not explain the relationship be-tween symptoms and amphetamine use since therelationship persisted when prior symptoms wascontrolled for in multivariate logistic and linearregression analyses.

The strongest reason for inferring that chronicamphetamine use causes severe psychologicalsymptoms of the type we observed is provided byan abundance of clinical and experimental evi-dence. In 1959 the English psychiatrist Connell*documented a large number of cases of paranoidpsychoses that occurred among chronic am-phetamine users, including people without anyevidence of a personal or family predisposition todevelop a psychosis. American investigators alsodocumented the association between paranoidpsychoses and heavy chronic amphetamine use,especially by injection.'*''* Subsequently, otherresearchers demonstrated in studies that wouldnowadays be regarded as unethical that thesymptoms of "amphetamine psychosis" could bereproduced by the injection of large doses ofamphetamine in amphetamine addicts," andmost critically by the repeated injection of largedoses of amphetamine in normal volunteers.^"

The major novelty in the present study wasthat we can be more confident that these psycho-logical symptoms were of sufficient severity andduration to distress many of the users who ex-perienced them. Together with other observa-tions, these findings reinforce our previousrecommendations that amphetamine users'"should be encouraged to avoid injecting the drugand to avoid regular use by whatever route. Thisrecommendation is specially salient for peoplewith a prior history of severe psychological symp-toms.

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