Most drugs of abuse are addictive. Addiction is a chronic, relapsing disease characterized by compulsive drug seeking and use despite negative consequences and by long-lasting changes in the brain. People who are addicted have strong cravings for the drug, making it difficult to stop using. Most drugs alter a person’s thinking and judgment, which can increase the risk of injury or death from drugged driving or infectious diseases (., HIV/AIDS, hepatitis) from unsafe sexual practices or needle sharing. Drug use during pregnancy can lead to neonatal abstinence syndrome, a condition in which a baby can suffer from dependence and withdrawal symptoms after birth. Pregnancy-related issues are listed in the chart below for drugs where there is enough scientific evidence to connect the drug use to negative effects. However, most drugs could potentially harm an unborn baby.
Hormone replacement therapy has been shown to have other beneficial effects. In a study women taking estrogen through HRT showed that the estrogen positively affects the prefrontal cortex by boosting the working memory. This suggests that estrogen may play a key role in certain frontal lobe functions in women.  Women using HRT after menopause have no additional weight gain compared to women who do not use HRT.  Also women who use HRT with an estrogen component show positive effects in their sex life (mainly increasing their sex drive and sexual sensitivity) but the effects are inconsistent across women. These sexual improvements may dissipate after receiving some forms of HRT for extended periods of time.