Half-life: The time it takes for half of the medication to leave the body. For instance, Paxil has a short half-life, leaving the body in about a day, whereas Prozac, which has a longer half-life, takes a week.
Black-box warning: The most serious type of label applied to prescription drugs by the Food and Drug Administration (FDA). For instance, the FDA requires that all antidepressants carry a black-box warning about the potential increased risk of suicidal symptoms in 18- to 24-year-olds.
Side effects: Adverse effects caused by medication.
Discontinuation syndrome: One or more side effects that occurs when individuals stop taking medication abruptly, including dizziness, headache, insomnia and numbness. For more on discontinuation syndrome, see here and here.
Antidepressants: A group of medications used to treat mood disorders, including depression, by acting on neurotransmitters in the brain – namely dopamine, serotonin and norepinephrine. The following are types of antidepressants: selective serotonin reuptake inhibitors (SSRIs); serotonin and norepinephrine reuptake inhibitors (SNRIs); tricyclic antidepressants (TCAs); and monoamine oxidase inhibitors (MAOIs).
Antipsychotics (or neuroleptics): Developed in the mid-1950s, these medications are known as traditional or typical antipsychotics. They treat severe mental disorders such as schizophrenia by reducing symptoms such as hallucinations and delusions. Antipsychotics have a risk of extrapyramidal side effects, including tremors, slurred speech, akathisia (shakiness and fidgeting) and tardive dyskinesia (involuntary movements). Other medications, including Prozac, Zoloft and Lithium, also may cause tardive dyskinesia.
Atypical (or “second generation”) antipsychotics: Developed in the 1990s, this group of medications also treats psychotic symptoms. It’s the first line of treatment for schizophrenia and may be prescribed to treat the manic phase of bipolar disorder. Overall, tardive dyskinesia and extrapyramidal symptoms occur less often with atypical antipsychotics. However, recent studies suggest that Abilify may cause akathisia.
Atypical antipsychotics also may raise the risk of obesity, diabetes and high cholesterol. Clozapine is an effective atypical antipsychotic, but is usually prescribed when other medications don’t work, because of its ability to reduce white blood cells (which fight infection) in some people.
Monoamine oxidase inhibitors (MAOIs): Used in the 1950s, MAOIs were the first antidepressants on the market. They work by metabolizing dopamine, norepinephrine and serotonin to help boost mood. These medications typically are prescribed when other antidepressants haven’t worked, because they require stringent dietary restrictions.
Selective Serotonin Reuptake Inhibitors (SSRIs): This group of newer antidepressants acts on the neurotransmitter serotonin by blocking its reuptake (reabsorption). It’s believed that higher levels of serotonin in the brain will help mood. The most famous SSRI is Prozac, which was introduced in 1987. Common side effects include sexual problems, trouble sleeping, nausea, dizziness and weight gain. Mayo Clinic offers advice on reducing SSRI side effects.
Serotonin norepinephrine reuptake inhibitors (SNRIs): A class of medications that inhibits the reuptake of both serotonin and norepinephrine. Common side effects resemble those for SNRIs but typically cause fewer sexual problems. Effexor (venlafaxine) can cause high blood pressure at high doses, so it’s important to have your blood pressure checked regularly.
Tricyclic antidepressants (TCAs): An older group of medications, TCAs are prescribed when newer antidepressants are ineffective to treat depression. They’re also prescribed for bipolar disorder. TCAs either work on serotonin, norepinephrine or both (called “dual action”). They may not be safe for individuals with heart disease and may be fatal in overdose.
Mood stabilizers: These medications help to regulate mood and are prescribed for bipolar disorder and borderline personality disorder. Examples include lithium and anti-seizure medications, such as Depakote, Tegretol and Lamictal. Side effects include weight gain and nausea.
Benzodiazepines: A group of fast-acting medications, including Xanax, Ativan and Valium, that treats anxiety, panic disorder, insomnia and sometimes bipolar disorder. Benzodiazepines act on the gamma-aminobutyric (GABA) receptors, inducing relaxation. When used for a long time or in high doses, benzodiazepines may cause physical dependence. Stopping abruptly can trigger severe symptoms, including anxiety, irritability, difficulty sleeping, muscle cramps and confusion.
Stimulant medication: Medications used to treat attention deficit hyperactivity disorder (ADHD), including methylphenidates (Ritalin) and amphetamines (Adderall). Stimulant medications increase dopamine levels, affecting the core symptoms of ADHD: inattention, impulsivity and hyperactivity. Side effects include reduced appetite and sleeping problems, but these tend to go away after several weeks or after adjusting the dose.
Serotonin: Chemical in the brain that regulates mood, sleep, sex drive, appetite, memory and learning, body temperature and behavior.
Dopamine: Neurotransmitter that controls pleasure-seeking, emotion, attention and movement.
Norepinephrine: Neurotransmitter that regulates blood pressure, heart rate and respiration.