A Little Logic Problem

Following problem has been taken from a German column called ``Logeleien von Zweistein'' and translated to English:
Psychiatrist Dr. Riddle has examined his patient Mr. Neuroman thoroughly. Now Mr. Neuroman asks: ``What is up with me, Doc?''. Dr. Riddle answers:
``Poor man, you are hysterical, or megalomaniac, or both. If you are megalomaniac without having a inferiority complex, you have obsessions. I can say for sure that you do not have both, obsessions and depressions. You do not have depressions in case of a inferiority complex. Please be informed that nobody can have depressions and be hysterical at the same time. In case of obsessions, you are not megalomaniac but you can safely assume a inferiority complex. However, if you have no obsessions, you suffer from depressions.''