Anxiety

Amygdala

The threat detector. Dense in androgen receptors, and the structure most implicated in the anger, vigilance and fear side of what these compounds do. Splitting it out of the limbic system matters because threat processing and reward processing sit in the same blob otherwise, and compounds pull them in opposite directions.

HPA Axis Activity

The stress axis: hypothalamus to pituitary to adrenal cortex, ending in cortisol. Relevant to mood twice over. A compound that blocks the glucocorticoid receptor removes the brake the axis runs on, and a compound that shuts down the gonadal axis leaves this one carrying more of the load.

Sympathetic Tone

How hard the fight-or-flight side of the nervous system is running. Androgens raise tyrosine hydroxylase and change adrenergic receptor density, so a compound can lift this without touching mood directly. It is the shared cause behind a cluster people treat as four separate problems: a higher resting pulse, night sweats, a short fuse, and sleep that will not come.

GABA-A Receptor

The brain's main calming channel. Some androgen metabolites sit on it as neurosteroids and change anxiety and sleep quality without touching the androgen receptor at all.