Abstract: Six RCTs involving 439 participants with dementia were included in the review, but no studies of participants with MCI were identified. The studies included people with dementia living in the community or in nursing home care and were carried out in several countries. Only one of the studies was classified as low risk of bias. Five studies were at unclear or high risk of bias due to uncertainties around randomisation, blinding and selective reporting of results. The studies used the different psychological approaches of cognitive behavioural therapy (CBT), interpersonal therapy and counselling. Two studies were of multimodal interventions including a specific psychological therapy. The comparison groups received either usual care, attention-control educational programs, diagnostic feedback or services slightly above usual care. Meta-analysis showed a positive effect of psychological treatments on depression (6 trials, 439 participants, standardised mean difference (SMD) -0.22; 95% confidence interval (CI) -0.41 to -0.03, moderate quality evidence) and on clinician-rated anxiety (2 trials, 65 participants, mean difference (MD) -4.57; 95% CI -7.81 to -1.32, low quality evidence), but not on self-rated anxiety (2 trials, SMD 0.05; 95% CI -0.44 to 0.54) or carer-rated anxiety (1 trial, MD -2.40; 95% CI -4.96 to 0.16). Results were compatible with both benefit and harm on the secondary outcomes of patient quality of life, activities of daily living (ADLs), neuropsychiatric symptoms and cognition, or on carers' self-rated depressive symptoms, but most of the studies did not measure these outcomes. There were no reports of adverse events. We found evidence that psychological interventions added to usual care can reduce symptoms of depression and clinician-rated anxiety for people with dementia. We conclude that psychological interventions have the potential to improve patient well-being. Further high quality studies are needed to investigate which treatments are most effective and to evaluate the effect of psychological interventions in people with MCI.

Plain-language summary: This review identified six randomised controlled trials, including 439 participants, in which a psychological treatment for people with dementia was compared to usual care. Most participants had mild dementia, but one trial was conducted with nursing home residents who had more severe dementia. We found no trials of participants with MCI. The psychological interventions used were based on established psychological models such as cognitive behavioural therapy (CBT), counselling, and interpersonal psychodynamic therapy. In two trials, the psychological treatment was combined with other interventions. We found evidence that psychological treatments can reduce depressive symptoms in people with dementia. There was also some evidence from two trials that CBT may reduce clinician-rated anxiety symptoms in people with mild dementia. Due to the imprecision of our results, we could not tell whether psychological treatments had an effect on patients' quality of life, ability to perform daily activities, overall psychiatric symptoms, or cognition, or on carers' self-rated depressive symptoms, but most studies did not measure these outcomes. Although these results are promising, the small number of studies and the variation between them in the type and duration of treatment make it difficult to draw conclusions about the best way to provide psychological treatment for people with dementia who have symptoms of depression or anxiety. More high quality trials in this area would be beneficial, including trials involving participants with MCI.