Table 1.

Adult neurogenesis.

Positive regulators	Negative regulators
Estrogen	Persistent emotional stress
Testosterone	Adrenal steroids like cortisol
A low stress environment	Sleep depravation
Sleep	Alcohol abuse
Physical activity	Excitatory inputs mediated by N-methyl-D-aspartate (NMDA)
SSRI’s	Limited learning opportunities and a relatively deprived environment
Mood stabilizing psychotropics/antiepiletics	Environmental complexity and intellectually enriched environments
Intellectual activity and learning