Seven trials (942 patients) were included in the review. Sample size ranged from 19 to 327 patients. Methodological quality scores on the PEDRO scale ranged from 5 to 9 points. Five trials reported adequate follow-up. Intention-to-treat analyses were performed in two trials.
Motivational interviewing was associated with significant reductions in alcohol use in three studies where the intervention was used in a single session, three sessions, and for sessions over four to six hours, compared with treatment as usual and an educational intervention. Effect sizes from baseline to first follow-up ranged from -0.90 (95% CI -1.50 to -0.30) to -0.71 (95% CI -1.07 to -0.35). Non-significant reductions were also observed with motivational interviews and cognitive behavioural therapy in two studies compared with treatment as usual. One trial found no significant differences between groups in quantity of alcohol use but found significant decreases in frequency of alcohol use.
Some control treatments were associated with decreases in alcohol use, including assessment with substance misuse service referrals (effect size -0.66, 95% CI -1.05 to -0.26), and assessments and provision of self-help booklets (effect size -0.68, 95% CI -1.08 to -0.29).
The intervention groups in two trials experienced reductions in psychiatric symptoms at 12 months follow-up; in one trial motivational interviewing and cognitive behavioural therapy administered over 10 sessions was associated with significantly less depression at six months follow-up and improved function at 12 months. In another trial, significantly lower psychiatric symptom scores were observed at 18 months for the experimental group of motivational interviewing and cognitive behavioural therapy (data not reported for these outcomes)