Objectives: The drug-related locus of control scale (DR-LOC) is a new instrument for assessing a person’s belief of “being in control” in situations involving drug abuse. It consists of 16-item pairs presented in a forced-choice format, based on the conceptual model outlined by Rotter. The model characterizes the extent to which a person believes that the outcome of an event is under their personal control (internal locus of control) or the influence of external circumstances (external locus of control).
Methods: A total of 592 volunteers completed the DR-LOC and the Rotter’s I-E scale. Approximately half of the respondents were enrolled in a drug treatment program for opiates, stimulants and/or alcohol dependence (n=282), and the remainder (n=310) had no history of drug dependence.
Results: Factor analysis of DR-LOC items revealed 2 factors reflecting control beliefs regarding (i) the successful recovery from addiction, and (ii) decisions to use drugs. The extent to which a person attributes control in drug-related situations is significantly influenced by their personal or professional experiences with drug addiction. Drug-dependent individuals have a greater internal sense of control with regard to addiction recovery or drug-taking behaviors than health professionals and/or non-dependent control volunteers.
Conclusions: The DR-LOC has shown to effectively translate generalized expectancies of control into a measure of control expectancies for drug-related situations, making it more sensitive for drug-dependent individuals than Rotter’s I-E scale. Further research is needed to demonstrate its performance at discriminating between heterogeneous clinical groups such as between treatment-seeking versus non–treatment-seeking drug users.
*Department of Psychiatry
†Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, UK
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This work was funded by an MRC research grant and conducted within the Behavioural and Clinical Neuroscience Institute, (supported by a joint award from the Medical Research Council and the Wellcome Trust).
The authors declare no conflict of interest.
Reprints: Karen D. Ersche, PhD, Department of Psychiatry, University of Cambridge, Herchel Smith Building, Cambridge CB2 0SZ, UK (e-mail: firstname.lastname@example.org)