Depression and Anxiety: Overview and Risk Factors

Sadness, anxiety, and mood swings occur normally in the course of any eventful life. However, they become problematic when they are severe enough to interfere with normal functioning, relationships, work or school performance, and other important activities of daily life.

Depression and anxiety are distinct disorders, but there are many similarities between them. They are discussed together here because their nutritional considerations are similar.

Depression is a common syndrome marked by sadness and a feeling of hopelessness. Additional symptoms may include poor concentration, feelings of guilt, sleep disturbances, appetite disturbances, sexual dysfunction, and hallucinations. The cause of depression is believed to involve abnormal levels of neurotransmitter chemicals in the brain (e.g., serotonin and norepinephrine), abnormal hormone levels (e.g., cortisol), genetic traits, and environmental and psychological factors.

Anxiety is marked by tension, excessive worry, and irritability. The brain chemicals norepinephrine, serotonin, and gamma-aminobutyric acid (GABA) may be involved in its development, and both genetic and environmental factors are believed to play a role.

Risk Factors

The following factors are associated with increased risk:

• Gender: Females are more likely to be diagnosed with depression.
• Family history
• Inadequate social supports: Examples include living alone or having few friends.
• Stressful life events: These might include retirement or the death of a loved one.
• Medical illness: Some studies show that up to 30 percent of patients who visit a physician with a physical symptom had either a depressive or anxiety disorder. Common medical illnesses associated with depression include heart disease, cancer, neurologic disease, and hormonal disease (e.g., hypothyroidism). Common medical illnesses associated with anxiety include heart disease, arrhythmias, congestive heart failure, mitral valve prolapse, asthma, chronic obstructive pulmonary disease, hyperthyroidism, hypoglycemia, Cushing's syndrome, Parkinson's disease, and cancer.
• Medications: Drugs associated with anxiety include bronchodilators (e.g., Albuterol), antidepressants, various blood pressure medications, steroids, psychostimulants (e.g., Ritalin), over-the-counter medications that contain caffeine, and pseudoephedrine (Sudafed).
• Drug intoxication or withdrawal: Drugs that may contribute to anxiety include caffeine, alcohol, cannabis, cocaine, methamphetamine, and nicotine. Some medications that are used to treat anxiety, such as benzodiazepines (e.g., alprazolam or Xanax), can cause rebound anxiety, in which individuals feel more anxious after the medication wears off than they did before taking it. This often leads to a cycle of increasing use.

Suicide is a risk in depressive illnesses, as in other psychiatric conditions. The risk factors for suicide include:

• A history of suicide attempts
• Suicidal thoughts
• Family history of suicide or attempts
• Access to weapons
• Substance abuse
• Underlying medical illness
• Male gender
• Increasing age

Diagnosis

A detailed history and physical examination are necessary for all patients. This should include psychiatric history, medication use, substance abuse, and social history. A physical examination should rule out disorders that are associated with depression or anxiety, especially heart and hormonal diseases. Particular attention should be paid to medications, as many can contribute to depressive and anxiety disorders.

All patients should be asked about suicidal thoughts. In patients thought to be at risk, immediate psychiatric attention is necessary.

Laboratory testing is generally not necessary, except to evaluate for medical disorders (e.g., EKG, thyroid function tests, blood counts, and blood chemistries). Urine testing may also be necessary.

The criteria for diagnosis of a major depressive disorder include at least five of the following symptoms occurring on most days within a two-week period and causing significant interference with daily life:

• Depressed mood
• Diminished interest in or pleasure from most activities
• Significant weight loss or gain, or change in appetite
• Altered sleep (too much or too little)
• Fatigue or loss of energy
• Feelings of worthlessness or excessive guilt
• Diminished ability to think or concentrate
• Recurrent thoughts of death or suicide

The criteria for diagnosis of an anxiety disorder include at least three of the following symptoms:

• Excessive worry
• Restlessness
• Fatigue
• Difficulty concentrating or mind going blank
• Irritability
• Muscle tension
• Sleep disturbance

Treatment

• A wide variety of antidepressant and anti-anxiety medications are available. In many cases, several weeks of therapy are necessary before the medications take effect. Successful relief of symptoms occurs in about half of patients.
• Psychotherapy may be effective used alone or in combination with medications. Treatment with a combination of medication and psychotherapy may improve the results, especially in persons with chronic depression.
• Some studies suggest that exercise may be as helpful as medications for the treatment of depression.
• Hypnosis, meditation, exercise, relaxation techniques, and avoiding caffeine are helpful in treating anxiety disorders.
• There is evidence that depression and anxiety disorders are associated with nicotine; thus, quitting smoking may be helpful.

Depression and Anxiety: Nutritional Considerations

Diet may influence mood in several ways. For example, certain amino acids and other nutrients act as building blocks in the production of brain chemicals. Dietary carbohydrate and protein can influence the rate at which brain chemicals are built. Further, weight loss in obese persons is associated with improvement in mood.

Diabetes is associated with depression. Poor control of blood sugar may worsen depression and decrease the effectiveness of antidepressant medications. Studies have shown that depression often improves as blood sugar improves. In addition, individuals who are depressed are at an increased risk for diabetes.

The following nutrients are under investigation for their role in depression and/or anxiety:

• Folate and other B-vitamins: Low blood levels of folate and vitamin B₁₂ are associated with depression and may decrease the effectiveness of antidepressant medications. Increased dietary (and perhaps supplemental) intakes of these vitamins may be important in preventing or treating depression. Limited evidence suggests that elderly patients with depression respond better to antidepressant medication when given supplemental vitamins B₁, B₂, and B₆, compared with antidepressant treatment alone. These observations may help explain why consuming a traditional Chinese diet, which is high in folate, is associated with lower rates of depression.
• Omega-3 fatty acids: Depression is associated with lower levels of omega-3 fatty acids. Some, but not all, studies have found that in countries where intake of these fatty acids is higher, depression is less common. Controlled clinical trials have found improvements in depression when fish oils were administered along with standard antidepressants. It is not known whether botanical sources of omega-3s, such as flax oil, have the same effect.
• Botanical treatments: St. John's Wort is effective in as many as 50 to 70 percent of patients with mild depression. However, they have not shown to be effective in patients with severe depression. Passion flower (Passiflora incarnata), chamomile (Matricaria recutita), and lemon balm (Melissa officianalis) contain flavonoids that may have anti-anxiety effects. Kava is an herbal treatment with evidence of a significant anti-anxiety effect. However, it is no longer available, due to reports of liver failure in rare cases when high doses were taken.

The following treatments may be helpful, but require more study:

• S-adenosylmethionine (SAMe): SAMe is involved in the production of certain brain chemicals and proteins. In limited trials, SAMe has shown effects similar to those of medication in treating depression and may have fewer side effects.
• Inositol: Inositol is a substance found in many foods, including whole grain cereals and legumes. Limited studies have suggested that supplements at doses of 12 to 18 grams per day may reduce anxiety symptoms as effectively as anti-anxiety medications, with a low incidence of side effects.