COVID-19 was first identified in December 2019. As long as this type of coronavirus was new, the main way for governments to avoid the spread of the infection was enforced quarantine. Besides public health protection, quarantine can have a psychological impact on the residents, with main symptoms being angst, anxiety, depressive, and PTSD symptoms. As it has been found that character strengths can promote subjective wellbeing, the purpose of the study was to examine this relationship under the new situation of quarantine in the Greek population in adults who were in quarantine for at least two weeks. The total sample consisted of 354 participants who were aged 18–72-years-old. A total of 263 participants were women (74.3%), 91 were men (25.7%), and 94.6% of them were highly educated. The sample was a convenience sample. The tools used were PANAS, PERMA and finally VIA-114GR. The data analysis was completed using SPSS software version 26.0 (IBM Corp. Released 2019. IBM SPSS Statistics for Windows, Version 26.0. Armonk, NY, USA: IBM Corp) and EQS 6.1 (Multivariate Software Inc.: Encino, CA, USA, 2006). The results showed that love, curiosity, persistence, hope, and zest are strongly associated with subjective wellbeing, even in conditions such as quarantine, and can support specific aspects of it.

Background: Dementia is a global condition affecting over 55 million people. Since there is no treatment, non-pharmacological interventions aim to delay its progression in a safe and cost-effective way. The extant literature suggests that Positive Psychology Interventions (PPIs) can probably be effective for this purpose. The systematic review aims to assess the effectiveness of PPIs as non-pharmacological interventions for mild cognitive decline related to dementia by evaluating their effectiveness in cognitive functions and brain functioning in people with Subjective Cognitive Decline (SCD), Mild Cognitive Impairment (MCI), and mild Alzheimer’s disease dementia (AD). Methods: A comprehensive search conducted in the databases Scopus, PubMed, ScienceDirect and PsychINFO (December 2024–March 2025) published between 2015 and 2025 to identify records that met inclusion criteria: studies included patients with SCD, MCI and mild AD dementia, implemented PPIs, Randomized controlled trials (RCTs) and pre–post intervention studies with measurable outcomes, assess at least one of the following: cognitive functions and brain functioning. Results: The systematic review included 12 studies (N = 669 participants) that can answer the research question. Only mindfulness interventions were identified. Findings suggest that different types of mindfulness interventions, such as the Mindfulness Awareness Program (MAP) and Mindfulness Training (MT), may be efficient for improving specific cognitive functions (e.g., working memory and attention) and influencing biological pathways related to cognitive decline. However, long-term efficacy has not been demonstrated, and results are mixed and unclear. Conclusions: Μindfulness interventions seem promising for enhancing cognition and brain functioning in older adults with cognitive decline, although the data is limited. However, limitations such as the heterogeneity of the studies and the diversity of the interventions make it necessary for more systematic and organized research to be conducted on the implementation of such interventions. At the same time, it is proposed to examine the effectiveness of other constructs of positive psychology, such as character strengths (CS).