Table 1.

List of studied resilience factors.

Resilience factor	Definition
Active coping (e.g., problem-solving)	Coping as a set of intentional, goal-directed efforts to minimize physical, psychological and social harm of stressors [83]; active coping as utilization of psychological and behavioral efforts that use own resources to handle a stressor [100].
Cognitive emotion regulation (e.g., positive reframing)	Conscious thoughts by means of which individuals regulate their emotions in response to stressors [26]. Positive reframing, as a type of reappraisal, describes thinking about negative or challenging situations in a positive way (e.g., thinking about the benefits or upsides of a negative event) [101].
Humor	Humor represents the capacity to perceive or express the amusing aspects of situations [102].
Hardiness	Hardiness is an ability to handle unexpected changes (challenges) with ease, combined with a sense of meaning in daily life (commitment) and personal control (control) [92].
Locus of control/control beliefs	Locus of control represents the degree to which people believe that they have control over outcomes in their lives [6]. A strong internal locus of control reflects the belief that outcomes are primarily a result of own action, an external locus of control is associated with viewing external factors as primary causes of outcomes.
Optimism	Optimism reflects the extent to which people hold generalized favorable expectancies for the future [4].
Religiosity or spirituality	Religiosity and spirituality describe any feeling, thought, and behavior that arises from the search for the ‘sacred’. Religiosity also includes group or social practices, while spirituality refers to personal beliefs and experiences [103].
Self-efficacy	Self-efficacy describes an individual’s subjective perception of his or her capability to perform a specific behavior or to achieve something [5].
Sense of coherence	Sense of coherence is the key component of the salutogenesis concept [14]. Individuals with high levels of sense of coherence perceive their lives as comprehensible, manageable and meaningful [80]. Comprehensibility describes the perception of the environment as predictable, structured, and explicable. Manageability refers to the belief that available internal and external resources are sufficient to meet situational demands, and meaningfulness describes the belief that challenges are worthy of engagement and coping.
Sense of mastery	Sense of mastery describes a person’s belief that they are able to control important circumstances in their life [104].
(Perceived) social support	Perceived social support describes the network of social resources perceived by an individual [105].
Dispositional resilience	Dispositional resilience is a personality trait that helps individuals to cope with adversity and achieve successful adjustment and development in the face of stressors [106]. The concept is closely related to hardiness [92] .

The selection of resilience factors is based on an updated summary of resilience factors presented in Kunzler et al. [11]. and Schäfer et al. [26]. Other concepts that are discussed as resilience factors are hope (closely related to optimism), meaning and purpose in life (closely related to the meaningfulness component of sense of coherence), positive emotions/affect and self-esteem, with the latter two being investigated as resilience factor, resilience mechanism and resilience outcome [107, 108]. Recently introduced concepts like regulatory flexibility [93] were not included as they have not been examined in systematic reviews on resilience factors yet.