Mood Disorders - Depression
What is it?
For psychiatric purposes, a mood is defined as a sustained emotion. Depression and elation are the types of moods most commonly seen in mood disorders; others include anxiety and anger. Clinical depression and mania are diagnosed when feelings of sadness or elation are overly intense, continue beyond the expected impact of a stressful life event, or arise without apparent or significant life stress. Difficulty in functioning in everyday life is another characteristic differentiating mood disorders from normal emotional reactions.
Depression
Originally a strictly medical term, the word 'depression' has become common in everyday speech and is regularly used to refer to feelings ranging from everyday disappointments to major loss. However, it is important to distinguish between this understandable reaction to life events, and clinical depression. The dividing line is not a clear one as not everyone who is depressed experiences every symptom of the illness, and the severity of symptoms can vary according to the individual involved.
Clinical depression is the most common psychiatric problem in our society and takes several forms including major depression, dysthymia, cyclothymia, bipolar disorder and seasonal affective disorder (SAD). Research suggests that as many as 10 per cent of patients who visit a doctor are experiencing depression serious enough to affect their physical condition. The rate of major depression may be as high as one in four women and one in eight men. Sometimes depression is appropriate to a life event, such as bereavement, and does not need medical treatment.
Symptoms of mood disorders - depression
Symptoms of depression include persistent sad or empty mood, loss of interest or pleasure in everyday activities, decreased energy, fatigue, poor appetite with weight loss, increased appetite with weight gain, altered sleeping patterns, physical hyperactivity or inactivity, feelings of worthlessness, diminished ability to think or concentrate, aches and pains, and recurrent thoughts of death or suicide.
At least two weeks of lowered mood is considered to be the minimum period to warrant a diagnosis of major depression. Someone with minor depression may not feel bad all the time but may still feel a sense of gloom, and minor disappointments may affect them deeply. Major depression is more severe and health may be affected by self-neglect. The risk of suicide is high.
Diagnosis of mood disorders - depression
In an effort to build a framework for the study and treatment of mental illness, psychiatrists have defined criteria for diagnosing disorders such as clinical depression. One of the best known sets of criteria is contained in the Diagnostic and Statistical Manual of Mental Disorders published by the American Psychiatric Association. It is now in its fourth edition and is known as DSM- IV.
Causes of mood disorders - depression
Depression and other mood disorders are complex problems, the causes of which are not well understood. It seems likely that any explanation or approach that emphasizes only one factor as the cause of depression is misleading and simplistic. However, sometimes depression can occur due to another disorder or as a drug side effect, and in these cases it is known as secondary depression. Where there is no clear physiological cause, the disorder is known as primary depression and it seems likely that the disorder will have several contributory causes. Research has focussed on biological factors such as heredity, hormonal abnormalities, medication side effects, disease-related effects, nutritional deficiencies and psychological and social causes. Changes in brain levels of neurotransmitters, chemicals which serve as communication links between nerve cells, are often seen in depressed patients. For example, levels of noradrenaline and serotonin are reduced.
Treatment of mood disorders - depression
Treatment of mood disorders such as depression is a complex process and may involve psychotherapy and drug treatment. Drugs which have antidepressant effects usually alter levels of neurotransmitters, serotonin and noradrenaline, which are involved in the transmission of nerve impulses in the brain. There are several types and they have slightly different effects in the body. People respond differently to the various types of antidepressant drugs; and a person's symptoms, age, whether or not they have a physical illness, suicide risk, and response to previous medication may help to play a role in deciding what drugs are given. Types of antidepressant drugs include heterocyclic antidepressants, monoamine oxidase inhibitors and selective serotonin re-uptake inhibitors.
An appropriate exercise program is an important part of any treatment of depression.The effects of exercise in improving the symptoms of depression are well-documented. Several studies have shown that exercise can improve mood and increase the ability to handle stress. A nutritious diet, exercise, limiting alcohol and tobacco, and effective stress reduction techniques are also important in the treatment of depression.
Mood Disorders - Depression and diet
Many substances in food may affect mood by altering the levels of various neurotransmitters in the brain. It is possible that nutritional factors play a part in many mental illnesses and even marginal nutrient deficiencies can change the structure and function of the brain and nervous system, and affect behavior. Memory loss, confusion and fatigue can be the consequences of a poor diet. Nutrient intake may have a powerful effect on a person's mood, behavior and ability to learn before the better known physical symptoms of deficiency are obvious.
Almost any nutrient deficiency can result in depression. Many depressed people show signs of nutrient deficiencies but it is unclear in many cases whether these deficiencies are an actual feature of the disease or are secondary to malnutrition. When a mood disorder is caused by a nutrient deficiency, increased intake usually reverses the symptoms; although in certain cases, permanent damage may occur.
Food allergies may also be linked to depression, and eliminating offending foods from the diet may help to relieve symptoms. Avoiding caffeine-containing drinks and food additives is also advisable.
Carbohydrates and protein
Carbohydrate-rich foods raise brain levels of tryptophan and therefore serotonin, which can lead to feelings of wellbeing. It is no coincidence that people often crave carbohydrate-rich foods when they are feeling sad. This is particularly common in those suffering from SAD and premenstrual syndrome. In contrast to carbohydrates, high protein foods seem to decrease the levels of serotonin in the brain. Some research suggests that the amino acids, tyrosine and phenylalanine can help to improve the symptoms of depression. Foods high in these amino acids include turkey, chicken, and milk; and they are also available as supplements.
There is some research to suggest that diets high in sugar can aggravate depression. It may be that some people are particularly susceptible to the effects of sugar on mood while others are relatively unaffected. It is unclear exactly how sugar exerts these effects but anyone suffering from depression may find it helpful to try and cut down or eliminate sugary foods.
Vitamins, minerals and mood disorders - depression
B vitamins
Inadequate intake of zinc, vitamin B6, iodine, vitamin B12 and folic acid during early life may impair nervous system development and permanently alter function and behavior. Deficiencies of folic acid and vitamin B12 cause defects in red blood cell production and function, which can lead to a reduction in the amount of oxygen reaching the brain. This can lead to fatigue, depression and mental problems.
Serotonin is manufactured in the brain from the amino acid, tryptophan with the help of vitamin B6, vitamin B12 and folic acid. Thus serotonin levels are related to the availability of tryptophan and these vitamins.
While virtually any vitamin or mineral deficiency can affect mood, and many depressed people show signs of nutrient deficiencies, B vitamin deficiencies may be particularly common and are often found in psychiatric patients. Researchers involved in a 1991 study measured the B complex vitamin status at time of admission of 20 geriatric and 16 young adult nonalcoholic patients with major depression. Twenty-eight per cent of the patients were deficient in riboflavin, vitamin B6, and/or vitamin B12. However, the degree of vitamin deficiency did not appear to be related to the severity of the disorder.1
In a randomized placebo-controlled study published in 1992, researchers at Harvard Medical School assessed the effects of 10 mg each of vitamins B1, B2, and B6 in 14 geriatric inpatients with depression who were taking antidepressant drugs. The results showed that those patients taking the vitamins showed greater improvement in scores on ratings of depression and cognitive function when compared with placebo-treated patients.2
Thiamin
Thiamin plays an important role in nerve function and release of the neurotransmitter, acetylcholine, which affects several brain functions. Thiamin deficiency can lead to depression, psychosis, apathy, anxiety and irritability. Alcoholics and binge drinkers are especially prone to thiamin deficiency as alcohol depletes body stores. Thiamin has been used to treat some of the symptoms associated with alcohol abuse; such as the reduction in certain brain chemicals involved with memory and thought processes.
In a study done in Wales in 1997, researchers gave 120 young adult women either a placebo or 50 mg thiamin, each day for two months. The women were not thiamin-deficient. Before and after taking the tablets, mood, memory and reaction times were assessed. The women taking the thiamin reported that they felt more clearheaded, composed and energetic.3
Riboflavin
Riboflavin is essential for the proper development of nerves and blood cells, iron metabolism, the activation of vitamin B6 and the conversion of tryptophan to niacin. Deficiency may contribute to depression.4
Niacin
Niacin deficiency leads to anxiety, depression, insomnia, and eventually dementia. Niacin may exert beneficial effects due to increases in levels of the amino acid, tryptophan, which is a building block for both niacin and serotonin. Niacin supplements have been used with tryptophan to treat depression and some researchers report improvement in symptoms.
The psychiatric symptoms of the niacin deficiency disease, pellagra resemble the symptoms of schizophrenia and large doses of niacin have been used to treat schizophrenia. Studies have shown mixed results.
Vitamin B6
Vitamin B6 deficiency can cause the mental symptoms of irritability and depression. Vitamin B6 is vital for the healthy development and function of the nervous system. It is necessary for the conversion of tryptophan to serotonin, and even a marginal deficiency may affect neurotransmitter levels.
Vitamin B6 deficiency is often found in depressed people and several studies have shown that mood improves when vitamin B6 supplements are given. As estrogen may suppress vitamin B6 metabolism, supplements may be beneficial for pregnant women, and for those on the contraceptive pill or hormone replacement therapy (HRT) who suffer from mood swings and depression. Vitamin B6 is also used to treat stress conditions.
Folate
Folate deficiency leads to confusion, forgetfulness, insomnia, irritability, depression and mood changes. It is often seen in those affected by psychiatric disorders, particularly depressive illness, and may play a part in causing or aggravating psychiatric disturbances.
Borderline low or deficient folate levels have been detected in as many as 38 per cent of adults diagnosed with depressive disorders.5 Low folate levels have also been linked to poorer response to the antidepressant drug, Prozac. In a study published in 1997, researchers examined the relationships between levels of folate, vitamin B12, and homocysteine in 213 depressed patients taking Prozac. The results showed that people with low folate levels were more likely to have melancholic depression and were significantly less likely to respond to the drug.6 Folic acid supplements may improve mood in depressed people, especially those who are taking drugs which interfere with folic acid metabolism.
Vitamin B12
Vitamin B12 deficiency eventually leads to a deterioration in mental functioning, to neurological damage, and to a number of psychological disturbances including memory loss, dementia, moodiness, confusion and delusions. Vitamin B12 is involved in the manufacture of myelin, the fatty sheath protein which insulates the nerves. It is also essential in the formation of neurotransmitters and in the normal functioning of blood cells.
Vitamin B12 deficiency is more common in the elderly than in younger people, with around 15 per cent of elderly men and women affected. Supplementation can prevent irreversible neurological damage if started early, and have been shown to improve mental function. Elderly people with vitamin B12 deficiency may show psychiatric or metabolic deficiency symptoms even before anemia is diagnosed. Screening for low vitamin B12 levels is necessary in elderly people with mental impairment, although it has also been found that deficiency states can still exist even when blood levels are higher than the traditional lower reference limit for vitamin B12.
Iron
Iron deficiency is associated with fatigue and depression and has also been implicated in emotional, social and learning difficulties in children and adults. Iron is also involved in the production of several brain neurotransmitters.
Selenium
Selenium supplements may improve mood and reduce anxiety, fatigue and depression in those whose intake is low. A 1996 study done at the USDA Human Nutrition Research Center in San Francisco suggests that people with low selenium levels might experience depressed moods, supporting the idea that selenium plays a special role in the brain. However, the study did not find improvements with selenium supplementation in people eating a typical American diet.7
Herbal medicine and mood disorders - depression
St John's wort (Hypericum perforatum) is a well-known herbal treatment for depression. In a study published in 1996 in the British Medical Journal, researchers from Germany and America analysed the results of 23 clinical trials that looked at St John's wort in the treatment of depression.8 The trials involved 1757 patients with mild to moderately severe depression. They specifically investigated whether St John's wort was more effective than a placebo, whether it was as effective as standard antidepressant drugs, and whether it had fewer side effects than those drugs. When the results of the trials were put together, they showed that St John's wort extracts were significantly better than placebo. Fifty-five per cent of patients given St John's wort found that their symptoms improved, whereas only 22 per cent of patients in the placebo group showed improvement. Other herbs that can be used to treat depression and strengthen the nervous system include vervain (Verbena officinalis), oat straw (Avena sativa), skullcap (Scutellaria laterifolia) and lemon balm (Melissa officinalis). Kava (Piper methysticum) has been used to treat anxiety.