FIGURE 2.

Hypothetical sex-related mental disorder on exposure to high altitude (HA). Stress and hypoxia decrease the availability of 5-HT at HA; brain synthesis of the latter already being lower in women than in men. Moreover, estrogen (E)-mediated support of 5-HT is blocked by stress. The lack of 5-HT diminishes brown adipose tissue (BAT)–dependent heat generation. Metabolic energy already being reduced by hypoxia, and possibly also by goiter, which may consequently generate a tradeoff in order to prioritize the energy requirements of thermoregulation, possibly at the expense of synapse repair. Memory consolidation thereby being interfered could allow mood changes to surge; the latter, in turn, additionally enhancing stress and insomnia. A vicious circle may thus be installed, potentially triggering the generation of mental disorders. Line thickness indicates the magnitude of effects.