There is very little evidence regarding the effectiveness of psychological therapies for co-occurring GAD and AOD use disorders [1086]. Kushner and colleagues [1169] developed an integrated group CBT program for co-occurring anxiety and alcohol use disorders to address symptoms of anxiety, as well as the association between anxiety and the motivation to drink alcohol. The treatment was evaluated in an RCT of individuals in a residential treatment program for alcohol use disorders with co-occurring GAD, panic disorder, or SAD. Those randomised to receive the CBT program treatment experienced considerably better alcohol outcomes relative to the control group who received progressive muscle relaxation training, and both groups demonstrated a reduction in anxiety symptoms. However, only 38% of the sample had a principal diagnosis of GAD. Buckner and colleagues [1171] similarly developed an individual integrated CBT program for people with co-occurring anxiety and cannabis use disorders. In an RCT evaluating this program, people who received the integrated intervention were more likely to be abstinent from cannabis and reported greater reductions in anxiety severity following treatment compared to a control group receiving motivation enhancement therapy, and both groups used less cannabis, and reported fewer cannabis-related problems. However, only 25% of the sample had a principal diagnosis of GAD. Mindfulness-based interventions, comprising elements addressing relapse prevention, non-reactivity, and non-judgemental awareness have also shown promise among people with stimulant dependence and GAD [1178].
Based on a large body of evidence, the RANZCP guidelines recommend 8-12 sessions of face-to-face or guided digital CBT as the first-line treatment for GAD [1158]. Individual or group therapy have been found to be equally effective, but there is evidence to suggest that individual therapy is associated with greater treatment adherence, and greater and faster gains in worry reduction. Although other psychological therapies have been tested (e.g., applied relaxation, cognitive therapy, mindfulness and acceptance-based interventions, meta cognitive and psychodynamic therapies) there is insufficient evidence to recommend their use in the treatment of GAD at this time. For those experiencing moderate or severe GAD, or those who do not demonstrate sufficient improvement in response to CBT, the use of pharmacotherapies may be considered as an alternative or adjunctive treatment [1158].