IntroductionThe present study replicates and extends a pilot study conducted by Baker, Bloggs and Lewin (2001) which showed that conducting and evaluating brief cognitive behaviour therapy (CBT) in a randomised controlled trial among regular amphetamine users was feasible.
Participants and procedureA total of 282 people were screened for the study between October 2001 and September 2002. Of these, 214 regular (at least weekly) users of amphetamines were enrolled in the study from the Newcastle region of New South Wales (n=98) and from the Greater Brisbane region, Queensland (n=116).
MeasuresData were collected on demographic characteristics, past and present alcohol and other drug use and mental health, treatment history, amphetamine related harm and severity of amphetamine dependence (see Section 3 for recommended instruments). A random sample of urine screens was obtained at 6-month follow-up.
DesignParticipants were randomly assigned to either an active intervention (two or four sessions of CBT in addition to a self-help booklet) or control condition (self-help booklet alone). The self-help booklet was developed by the National Drug and Alcohol Research Centre (NDARC, 2001). Assessments were scheduled at pre-intervention, post-intervention (five weeks following pre-intervention assessment) and six months following the post-intervention assessment. Assessments were conducted by interviewers who were blind to participants' intervention allocation.
Cognitive behaviour therapy conditionsThis treatment guide, revised and expanded from that used in the pilot study (Baker et al., 2001), and a self-help booklet (NDARC, 2001) guided intervention sessions that focused on developing skills to reduce amphetamine use. Four sessions were conducted individually and lasted 45-60 minutes. In the two-session CBT condition, the procedure and content of the first two sessions was the same as that for the four-session intervention. Top of page
Control groupSubjects allocated to the control condition were assessed at pre-intervention, post-intervention and 6 month follow-up and were given the same self-help booklet as the intervention conditions at pre-intervention (NDARC, 2001).
TherapistsTherapists were University graduates (three psychologists and one social worker). A week-long training session was held at the commencement of the project. This covered research procedures and role-plays of assessment instrument administration and intervention sessions. Videotaped feedback was used to enhance training. Session checklists were employed to guide weekly supervision provided by the chief investigators (AB, NKL).
Summary of main resultsDetailed results of the study will be reported separately.
At pre-intervention, the current sample comprised a group of regular amphetamine users with long histories of amphetamine use who had high levels of dependence on amphetamines, injecting risk-taking behaviour, polydrug use, depression, psychiatric illness and poor quality of life. Although only 35% of the initial sample were at an action stage for reducing amphetamine use, 71.5% (153/214) were retained at 6 month follow-up. Almost three-quarters (72.14%, 101/140) of participants assigned to intervention conditions attended all sessions. Thus, regular users of amphetamines, many of whom are ambivalent about change, can be recruited, treated and retained for follow-up evaluation.
The results of the present study indicated that overall there was a marked reduction in amphetamine use among this sample over time and this was not differentiated by intervention group. This reduction was likely to be related to commitment to being in the project and to the assessment process.
However, being in the intervention group was significantly associated with abstinence, which implies active therapy gave subjects an added incentive for abstinence. Approximately one-quarter (13/48, 27.1%) of the participants in the control condition were abstinent from amphetamines at the 6 month follow-up, compared to 49.4% (42/85) of those who participated in two or more intervention sessions. Adjusting for the effects of duration of regular amphetamine use, this represents a significant increase in the likelihood of abstinence among those receiving two or more intervention sessions [Adjusted Odds Ratio (AOR) = 3.00, p < .01, 99% Confidence Interval: 1.06 to 8.44]. Self-report data was confirmed by urinalyses among a random sample of participants.
In addition, being in the intervention group had a significant short-term beneficial effect on depression. There were no intervention effects on any other variables (HIV risk-taking, crime, social functioning and health).