Mood and Cognition
Leading experts in the field of brain research have observed that “sex steroids exert profound effects on mood and mental state.”30 Many studies have established a direct relationship between decreased testosterone levels and negative mood factors such as depression, anger, confusion, anxiety, and fatigue.31 Wang et al. found that testosterone replacement used to restore androgen balance in hypogonadal men improved many emotional parameters, including friendliness, energy levels, and sense of well-being.32 Significantly, these benefits were maintained over the course of a six-month period of therapy, precluding the possibility of a short-term placebo effect.
Testing to establish baseline testosterone levels prior to replacement therapy is crucial for effectively treating sex-hormone-related mood disorders in men. Researchers stress there is a clear “threshold effect,” i.e., that positive benefits on mood achieved by therapy are only realized when initially deficient hormone levels are brought into the “normal” range. Replacement therapy applied to men with normal levels, or therapy that triggers higher than normal levels, usually provide negligible clinical benefit and may even trigger potential adverse affects.
Testosterone is believed to strongly influence cognitive function in the brain, particularly visuo-spatialization skills. This relationship exhibits a curvilinear relationship: spatialization skills in men decrease as salivary testosterone levels become either too low or too high.33-34 An increase in visuo-spatial ability gained through testosterone therapy, however, may be accompanied by a slight drop in verbal fluency ability — which some researchers relate to possible sex-based differences in physiological cognitive processes.35
Various mechanisms could explain testosterone’s powerful effect on cognitive function: experimental studies have revealed androgen binding sites in the hypothalamus and other regions in the brain.36 Other researchers suggest that the aromatization of testosterone to estrogen impacts both serotonin transport and 5-hydroxytryptamine 2a receptors in the forebrain, which play pivotal roles in emotion, memory, and cognition.37
