The stress vulnerability model was proposed by Zubin and Spring (1977). It proposes that an individual has unique biological, psychological and social elements. These elements include strengths and vulnerabilities for dealing with stress.

In the diagram above person “a” has a very low vulnerability and consequently can withstand a huge amount of stress, however solitary confinement may stress the person so much that they experience psychotic symptoms. This is seen as a “normal” reaction. Person “b” in the diagram has a higher vulnerability, due to genetic predisposition for example. Person “c” also has genetic loading but also suffered the loss of mother before the age of 11 and was traumatically abused. Therefore persons “a” and “b” take more stress to become “ill”.

This model is obviously simplistic. However it does help with the understanding of psychosis. Vulnerability is not a judgmental term but a different way to approach the variables involved. We all have a different capacity to take on stress depending on how vulnerable we are. At different times in our lives we can be anywhere on the curve, depending on these variables. 
Increasing coping skills or altering environmental factors (family, work, finance, housing etc.) and specialist help can reduce vulnerability and build resilience. Attending a peer group may help to build self-efficacy, self-esteem and self-acceptance all of which may be protective against relapse and form a buffer to demoralisation. It gives hope!