Poor social and economic situations have a long-term impact on health. Long-term stress can be caused by social and psychological factors. Stress also has a negative impact on health. Stress causes your body to produce chemicals called "stress hormones". High levels of these hormones cause problems with blood sugar regulation, increase the risk of heart disease, and weaken the immune system. Stress is a major factor in many illnesses and injuries such as diabetes, heart disease, and cancer. Social support plays an important role in maintaining good health. Having someone you can talk to about stress or personal problems reduces the effect of those stresses on your health. Social support also gives you something positive to look forward to each day. A positive attitude helps keep depression at bay and may help you live longer. Social issues affect health care too. For example, women who use drugs illegally will often not seek treatment because they cannot afford to pay for it. This can lead to pregnancy and HIV/AIDS. Drug abuse also leads to violence, which affects how others respond to trauma (such as a car crash). This in turn can affect health care decisions later in life. Healthy relationships are essential for good mental health.