An example biological vulnerability might be a family history of psychosis or a physical illness or disability.

"Susceptibility genes" have been identified for the development of schizophrenia and bi-polar disorder (e.g. Craddock, O Donovan and Owen (2005)

There is also evidence to suggest that people with chronic health problems are more likely to have mental health problems (and vice versa) - e.g. Mental Health Foundation, 2020)

Example biological protective factors might include good phyiscal health or compliance with medication.

Example psychological vulnerabilities might include low self esteem or experiencing abuse or trauma in childhood.

For example, low self esteem has been linked to the maintenance of persecutory delusions and hallucinations in people with schizophrenia

(Garety, Kuipers, Fowler, Freeman and Bebbington, 2001)

Example psychological protective factors might include participating in regular mindfulness or relaxation exercises or high self esteem and self efficacy.

Example social vulnerabilities might include isolation, low income, housing issues

A history of homelessness is common in patients with psychosis using inner urban mental health services and is associated with poorer engagement with psychiatric services. (Holmes et al, 2005)

Example social protective factors might include having stable housing and income, a supportive social network.

Notice that the persons vulnerability threshold remains the same; a persons vulnerability to mental health problems is likely to be due a combination of biological and early life experiences.

Day to day stressors cause varying amounts of stress; some of these may tip over the persons "vulnerability threshold" (leading to the development of psychotic symptoms).

Protective factors such as medication or psychological or social factors can "protect" against high levels of stress.