The stress-diathesis model explains how nature and nurture come together in the development of psychological disorders. It describes how a disorder or behaviour trait is the result of an interaction between genetic predisposition, vulnerability and stress, usually caused by life events and factors. Schizophrenia is caused by stress diathesis; children may inherit the gene for schizophrenia, so have a genetic predisposition to develop it. The environment can trigger the activation of the gene, for example by stress or smoking cannabis.