Thirty-six studies were included. This included 19 RCTs (n=2,573), 3 CTs (n=154) and 13 PPTs (n=1,934).
Overall psychological well-being (5 studies): one PPT reported that a self-management intervention significantly improved negative and positive aspects of well-being. The other 4 studies (CTS and PPTs) found no significant difference when compared with controls, or over time.
Depression (15 studies, including 6 studies classified as RCTs): four (3 psychological and 1 educational intervention) of the 6 RCTs showed that the intervention improved depression compared with standard treatment or education.
Seven (all self-management interventions) of the 8 PPTs showed that the intervention improved depression over time. The other PPT (psychological intervention) showed no improvement over time.
Anxiety (8 studies including 7 RCTs): 2 RCTs (1 psychological stress-management and 1 educational intervention) showed that the intervention reduced anxiety compared with controls. Five RCTs (1 educational, 1 self-management and 3 psychological interventions) showed no reduction in anxiety compared with controls. The PPT showed improvement over time with the intervention.
Emotional adjustment (4 studies, including 1 RCT): the RCT found no significant difference between a self-management and an educational intervention. Three PPTs (1 psychological, 1 educational and 1 self-management intervention) found significant or borderline significant improvements over time.
Quality of life (20 studies): one of the 7 studies using either the SF-36 or SF-20 found improvement on all sub-scales at 6 months. Three of the 6 CTs using diabetes-specific measures found that the intervention improved quality of life compared with controls. All 3 PPTs using diabetes-specific measures of quality of life found improved quality over time with the intervention. Three studies used other generic measures. One of these found that a behavioural, diet and exercise, or diet alone intervention improved quality of life compared with education, while another found no difference between adding community resources or telephone follow-up to self-management.
No psychological intervention assessed quality of life.