• Children and adolescents
• Older adults
• Women who are pregnant or may become pregnant.

Children and adolescents

Most medications used to treat young people with mental illness are safe and effective. However, many medications have not been studied or approved for use with children. Researchers are not sure how these medications affect a child's growing body. Still, a doctor can give a young person an FDA-approved medication on an "off-label" basis. This means that the doctor prescribes the medication to help the patient even though the medicine is not approved for the specific mental disorder or age.

For these reasons, it is important to watch young people who take these medications. Young people may have different reactions and side effects than adults. Also, some medications, including antidepressants and ADHD medications, carry FDA warnings about potentially dangerous side effects for young people. See the sections on antidepressants and ADHD medications for more information about these warnings.

More research is needed on how these medications affect children and adolescents. NIMH has funded studies on this topic. For example, NIMH funded the Preschoolers with ADHD Treatment Study (PATS), which involved 300 preschoolers (3 to 5 years old) diagnosed with ADHD. The study found that low doses of the stimulant methylphenidate are safe and effective for preschoolers. However, children of this age are more sensitive to the side effects of the medication, including slower growth rates. Children taking methylphenidate should be watched closely.^15,16,17

In addition to medications, other treatments for young people with mental disorders should be considered. Psychotherapy, family therapy, educational courses, and behavior management techniques can help everyone involved cope with the disorder. Click here for more information on child and adolescent mental health research.

Older adults

Because older people often have more medical problems than other groups, they tend to take more medications than younger people, including prescribed, over-the-counter, and herbal medications. As a result, older people have a higher risk for experiencing bad drug interactions, missing doses, or overdosing.

Older people also tend to be more sensitive to medications. Even healthy older people react to medications differently than younger people because their bodies process it more slowly. Therefore, lower or less frequent doses may be needed.

Sometimes memory problems affect older people who take medications for mental disorders. An older adult may forget his or her regular dose and take too much or not enough. A good way to keep track of medicine is to use a seven-day pill box, which can be bought at any pharmacy. At the beginning of each week, older adults and their caregivers fill the box so that it is easy to remember what medicine to take. Many pharmacies also have pillboxes with sections for medications that must be taken more than once a day.

Women who are pregnant or may become pregnant

The research on the use of psychiatric medications during pregnancy is limited. The risks are different depending on what medication is taken, and at what point during the pregnancy the medication is taken. Research has shown that antidepressants, especially SSRIs, are safe during pregnancy. Birth defects or other problems are possible, but they are very rare.^18,19

However, antidepressant medications do cross the placental barrier and may reach the fetus. Some research suggests the use of SSRIs during pregnancy is associated with miscarriage or birth defects, but other studies do not support this.²⁰ Studies have also found that fetuses exposed to SSRIs during the third trimester may be born with "withdrawal" symptoms such as breathing problems, jitteriness, irritability, trouble feeding, or hypoglycemia (low blood sugar).

Most studies have found that these symptoms in babies are generally mild and short-lived, and no deaths have been reported. On the flip side, women who stop taking their antidepressant medication during pregnancy may get depression again and may put both themselves and their infant at risk.^20,21

In 2004, the FDA issued a warning against the use of certain antidepressants in the late third trimester. The warning said that doctors may want to gradually taper pregnant women off antidepressants in the third trimester so that the baby is not affected.²² After a woman delivers, she should consult with her doctor to decide whether to return to a full dose during the period when she is most vulnerable to postpartum depression.

Some medications should not be taken during pregnancy. Benzodiazepines may cause birth defects or other infant problems, especially if taken during the first trimester. Mood stabilizers are known to cause birth defects. Benzodiazepines and lithium have been shown to cause "floppy baby syndrome," which is when a baby is drowsy and limp, and cannot breathe or feed well.

Research suggests that taking antipsychotic medications during pregnancy can lead to birth defects, especially if they are taken during the first trimester. But results vary widely depending on the type of antipsychotic. The conventional antipsychotic haloperidol has been studied more than others, and has been found not to cause birth defects.^23,24

After the baby is born, women and their doctors should watch for postpartum depression, especially if they stopped taking their medication during pregnancy. In addition, women who nurse while taking psychiatric medications should know that a small amount of the medication passes into the breast milk. However, the medication may or may not affect the baby. It depends on the medication and when it is taken. Women taking psychiatric medications and who intend to breastfeed should discuss the potential risks and benefits with their doctors.

Decisions on medication should be based on each woman's needs and circumstances. Medications should be selected based on available scientific research, and they should be taken at the lowest possible dose. Pregnant women should be watched closely throughout their pregnancy and after delivery.