ABSTRACT
The above citations from ancient times suggest that testosterone plays a role in behavior. Despite these early anecdotes, with the exception of studies on libido, there are few well-controlled studies examining the effect of testosterone on behavior. This is in contrast to the relatively large literature on estrogen in women, linking it to cognitive behaviors and perhaps to playing a role in Alzheimer’s disease.1,2
While testosterone has been strongly associated with the mythologic concept of the aggressive male, studies examining the effects of testosterone on behavior have yielded mixed results. Schaal et al3
found that high testosterone levels were more likely to be a marker of social success than to be associated with physical aggression. On the other hand, in free-ranging adolescent male non-human primates, cerebrospinal fluid levels of testosterone were associated with overall aggressiveness but not impulsivity.4 Administration of moderately high doses of testosterone for contraception has failed to reveal
adverse effects on male sexual and aggressive behavior.5 In a controlled trial supraphysiologic doses of testosterone failed to increase angry behavior in healthy eugonadal males.6 In males rendered hypogonadal with a GNRH antagonist there was not only a decrease in sexual desire and fantasies, but also a trend to increased aggression.7 In contrast, using a similar approach, Loosen et al8 found a reduction in outward-directed anger and no change in inward-directed behavior in hypogonadal males. Burris et al9 found that hypogonadal men were more angry than eugonadal men and that this anger decreased with testosterone therapy. A 48XXYY hypogonadal male had a reduction in long-standing aggressive fantasies and behaviors towards women.10
