Sigmund Freud skriver til sin venn og kollega Wilhelm Fliess om hvordan han forstår sin egen angstnevrose

Sigmund Freud skriver til sin venn Wilhelm Fliess i Berlin (her gjengitt i engelsk oversettelse -- originalen er på tysk):

« ... it occurs to me that the limits of repression in my theory of neuroses, that is to say, the time after which sexual experiences no longer have a posthumous but an actual effect coincide with the second denfition. It is only now that I dare to understand my anxiety neurosis: the menstrual period as its physiological model; the anxiety neurosis itself as an intoxication, for which an organic process must furnish the physiological foundation. The unknown organ (the thyroid or whatever it may be) probably will not, I hope, remain unknown to you for long. I was greatly delighted with the male menopause as well; in my "Anxiety Neurosis" I boldly anticipated it as the last condition [giving rise to anxiety neurosis] in men. (Masson, 1985, s. 174)