Abstract: The review includes 16 studies (eight new studies included in this update) representing data from 556 participants. Studies are diverse in their design and their methods. They cover interventions with generic approaches, as well as interventions developed specifically to target disease-specific symptoms and problems in people with cystic fibrosis. These include cognitive behavioural interventions to improve adherence to nutrition or psychosocial adjustment, cognitive interventions to improve adherence or those associated with decision making in lung transplantation, a community-based support intervention and other interventions, such as self-hypnosis, respiratory muscle biofeedback, music therapy, dance and movement therapy, and a tele-medicine intervention to support patients awaiting transplantation. A substantial proportion of outcomes relate to adherence, changes in physical status or other specific treatment concerns during the chronic phase of the disease. There is some evidence that behavioural interventions targeting nutrition and growth in children (4 to 12 years) with cystic fibrosis are effective in the short term. Evidence was found that providing a structured decision-making tool for patients considering lung transplantation improves patients' knowledge of and expectations about the transplant, and reduces decisional conflict in the short term. One study about training in biofeedback-assisted breathing demonstrated some evidence that it improved some lung function measurements. Currently there is insufficient evidence for interventions aimed at other aspects of the disease process. Currently, insufficient evidence exists on psychological interventions or approaches to support people with cystic fibrosis and their caregivers, although some of the studies were promising. Due to the heterogeneity between studies, more of each type of intervention are needed to support preliminary evidence. Multicentre studies, with consequent funding implications, are needed to increase the sample size of these studies and enhance the statistical power and precision to detect important findings. In addition, multicentre studies could improve the generalisation of results by minimizing centre or therapist effects. Psychological interventions should be targeted to illness-specific symptoms or behaviours to demonstrate efficacy.

Plain-language summary: We looked for studies of psychological treatments in individuals of all ages with cystic fibrosis and their families which aimed to reduce anxiety and depression, to improve adjustment, quality of life, and even medical outcomes, as well as knowledge, skills, and decisions regarding care. The review includes 16 studies with a total of 556 participants. Even though there many different psychological interventions, only a few have been evaluated for individuals with CF and their families. Due to the lack of high quality studies, it is not possible to currently show which psychological treatments are most helpful to those with cystic fibrosis and their caregivers. Five out of the 16 studies we found evaluated behavioural interventions to improve dietary intake. We found that in children aged 4 to 12 years receiving a nutritional intervention plus behavioural management training, consumed about 276 per day more than children just receiving the nutritional intervention. We also found that a structured decision-making tool for adults considering lung transplantation improved their knowledge, assisted in setting realistic expectations, and reduced indecision. In summary, there is some evidence that behavioural interventions targeting specific illness-related symptoms and behaviours can work. More studies on psychological interventions with more people are urgently needed. There are several ongoing randomised controlled studies aimed at improving adherence to prescribed treatments, but final results are not yet available. We recommend multicentre studies to provide evidence for which interventions are most effective for the key issues faced by people with cystic fibrosis and their caregivers.