Personality traits play an increasing role in research on the vulnerab
ility to mental disorders. Problems of their assessment are dealt with
here with special reference to work of our own in this area. Personal
ity inventories for self-rating or informants' rating are appropriate
instruments for retrospective as well as prospective investigations. T
hey should be short and, at the same time, suites for the assessment o
f the main dimensions of personality, the ''Big Five''. The Munich Per
sonality Test (MPT) and the Six Factor Test (SFT) serve as examples in
this context. They were already successfully applied in clinical and
outpatient settings and in ''high-risk'' studies. In retrospective inv
estigations, a newly developed method for the operationalized diagnosi
s of personality types from case history data can be used as well. On
the basis of this approach, we have recently developed a Biographical
Personality Interview (BPI) which, in combination with personality inv
entories, can be regarded an optimal device for the assessment of prem
orbid personality in psychiatric patients.