The purpose of this study is to investigate the effects between Standard Cognitive Behavioural Therapy [CBT(S)] and Brief Cognitive Behavioural Therapy [CBT(B)] on locus of control among drug abusers. The quasi-experimental design with two treatment group [CBT(S) and CBT(B)] and one control group (CG) and four repeated measurements (pre, post1, post 2, and post 3) were employed in this study. The sample of 108 drug abusers was chosen using purposive sampling procedure. Sample was then distributed randomly into three groups; CBT(S), CBT(B) and control group (KW). Each group consisted of 36 samples. Data were collected with standardized psychometric instruments, Internal Control Index. Data were analysed using two-way ANOVA repeated measurement. Result demonstrated significant differences among group CBT(S), CBT(B) and CG on locus of control mean score [F(2, 13.38)=200.4, p<.05]. The impact of study shows that CBT(S) and CBT(B) intervention are able to increase locus of control among the drug abusers.
