Part 1: Anxiety And Depression

The Depression and Anxiety Epidemic

Mood disorders such as anxiety and depression are becoming increasingly prevalent in the Western countries of the developed World. The prevalence of anxiety within the general population has been estimated to be between 5 and 20 % in the general population, and in many cases anxiety is chronic. Further, it is estimated that 6 to 12 % of the population has a specific phobia, with phobias being the most common of any anxiety disorder. Fear of flying is a common phobia. People with anxiety disorders have been shown to have a significant reduction in the quality of life, with anxiety being as debilitating as physical disabilities and diseases. Sleep disturbances and general stress are a particular burden to those who suffer from anxiety.

Cases of depression are also increasing. The prevalence of major depression in Western countries may be around 10 %, with mild to moderate depression having a prevalence of around 6 % of the population. Some studies show that around half of those who experience a depressive episode recover within 3 months. However, the rate of recovery slows at 12 months, and by 24 months 20 % of subject may still be suffering from depressive symptoms. Like anxiety, depression can therefore become chronic and debilitating. Sleep disturbances and general stress are also common in those with depression.

In individuals with existing health complaints, the prevalence of anxiety and depression may be even higher. For example, the prevalence of depression may be as high as 57 % in cancer patients and as high as 25 % in pregnant mothers and those who have recently given birth. Anxiety disorder in those with diabetes may be as high as 27 %.

Anxiety and depression can therefore be considered widespread, chronic and debilitating disorders that affect a substantial proportion of the population of Western countries. The increase in anxiety and depression in Western society may relate to the way our lives have become more mentally stressful. Job stress, job shortages, debt, housing shortages, social breakdown, social isolation, and the constant fear peddled by the media and government provide a continual source of stress to the population. It is not surprising that mental health issues such as anxiety and depression are therefore increasing.

anxiety and depression

The prevalence of anxiety and depression is Western society are increasing. This may relate to the increasingly hectic and stressful lives we live.

At the same time as our lives have become more stressful, diet quality has declined. People living in the Western nations generally consume the typical Western diet, and this has been shown to lead to a slow and general deterioration in health. Therefore a situation has arisen whereby the diet of most individuals is not good enough to supply the necessary nutrients required, and this may be detrimentally affecting general health. It is known that stress increases the requirements for particular nutrients, and so a high stress environment, alongside a poor quality diet, may create the perfect storm for the development of mood disorders.

Studies show that about 10 to 15 % of adult population suffer from chronic insomnia. In addition to this, around 25 to 35 % of the adult population suffer from transient insomnia. Sleep disorders are common in both anxiety and depression, and in young adults poor sleep quality is most closely associated with major depressive disorder. However, anxiety is also strongly associated with poor sleep quality in young adults. The poor sleep quality associated with mood disorders can lead to lethargy, mental fatigue, physical fatigue and further deteriorations in mental health. Poor sleep patterns lower life expectancy and there is good evidence that this results from a general deterioration in health associated with a lack of good quality sleep.

What are Depression and Anxiety?

Depression is the most commonly diagnosed mood disorder in adults. While once depression was once seen as transient, is it now unfortunately being seen as a more chronic and therefore debilitating illness. Depression is generally characterised by a continual negative outlook in life that impinges on the ability to perform normally within society. This leads to a reduction in the quality of life for the individual.

The DSM is the ‘Diagnostic and Statistical Manual of Mental Disorders’ as used by psychiatrists for diagnostic purposes. In the DSM depression is defined by the presence of a number of symptoms that persist for a specific period of time. These symptoms include the presence of depressed mood, diminished interest in daily activities, weight change, insomnia or oversleeping, agitation, fatigue, feelings of worthlessness, diminished ability to concentrate and recurrent thoughts of death. Five or more of these symptoms persisting for the same 2 week period, as a change from previous functioning, in combination with depressed mood and loss of interest in pleasure, signifies the development of ‘major depressive disorder’ (MDD; commonly called depression).

The World Health Organisation (WHO) uses slightly different criteria to define depression. The WHO definition includes a loss of interest in activities, lack of emotional reactions, sleep disturbance, loss of appetite, motor retardation (muscle fatigue), weight loss, loss of libido, and decreased energy. The WHO also states that depression can include feelings of a lack of self worth and feelings of guilt. There may also be thoughts of self harm or suicide. However, despite small differences, the DSM and WHO definitions are broadly in agreement.

Anxiety is different to depression because it is characterised by feelings of uncontrolled uneasiness and fear, often with no apparent cause. A growing number of individuals suffer from an undiagnosed milder form of chronic anxiety for which they never seek medical attention. This low grade anxiety appears to be fairly common amongst the general population of the Western nations, and it is often put down to the stress of daily life. This sort of chronic low grade anxiety is termed the generalised anxiety disorder (GAD). Anxiety is a common disorder in the modern Western World, with estimates indicating that 7.3 % of people in the United States may be sufferers.

The DSM defines generalised anxiety disorder as excessive anxiety or worry, occurring on more days than not, with the symptoms lasting for at least 6 months. The individual finds it difficult to control the worrying feelings, and the anxiety is associated with three or more of the following; restlessness, being easily fatigued, having difficulty concentrating, irritability, muscle tension and sleep disturbance. These symptoms cause a significant impairment at work and home, and the disturbance is not attributable to a drug.

anxiety depression

Depression is characterised by feelings of helplessness, worthlessness or hopelessness. Anxiety is characterised by fear, agitation and worry. The increasingly authoritarian lives we live are undoubtedly contributing to the development of serious mood disorders in Western populations through the development of excessive levels of stress.

People with generalised anxiety disorder tend to suffer low levels of anxiety most days, and often they do not remember what triggered the anxiety or when it began. Evidence suggests that generalised anxiety disorder is characterised a low level chronic activation of the fear circuitry of the brain. This leads to a constant general feeling of discomfort and uneasiness that can impinge on a person’s life considerably. A similar condition called adjustment disorder with anxious mood (ADWAM) is a transient anxiety caused by an identifiable stressful event. Increasingly, young adults, teenagers and even children are suffering from generalised anxiety disorder and adjustment disorder with anxious mood.

Panic attacks are a paroxysmal (severe and acute) form of anxiety that can be transient but severe in nature. Panic attacks can be more debilitating in their negative effects than generalised anxiety disorder. It has been estimated that between 1 and 2 % of the population of the United States may suffer regularly from panic attacks with 35 % of the population having had at least one panic attack. Panic attacks can be hugely debilitating for the individual, and sufferers have an increased risk of mortality, particularly from cardiovascular disease and suicide.

Obsessive compulsive disorder (OCD), post traumatic stress disorder (PTSD) and phobias are also forms of severe anxiety. Severe anxiety often requires medical intervention including the use of psychiatric drugs, as the symptoms can overwhelm the resources of the individual and be highly debilitating. All anxiety can cause physiological changes such as sweating, rapid breathing, shaking, and hypertension, but these are most obvious in cases of severe anxiety. Irritable bowel syndrome and other chronic and ‘idiopathic’ gastrointestinal disorders may also be caused by anxiety.

What Causes Anxiety and Depression?

The causes of anxiety and depression are not always obvious. Post traumatic stress disorder and adjustment disorder with anxious mood are generally caused by specific events that can be recorded. For example combat soldiers can suffer from post traumatic stress disorder following harrowing experiences in battle. The death of a spouse may be the trigger of adjustment disorder with anxious mood. However, depression, generalised anxiety disorder, phobias, obsessive compulsive disorder and panic attacks are not so readily attributable to a known single event or series of events. Therefore identifying a cause is not easy, or often not possible at all.

One of the most likely causes of depression and the generalised anxiety disorder is chronic stress. Animal models of anxiety and depression often use stresses such as exposure to cold water, exhaustive physical activity, maze tests, lack of food, difficult living conditions, and general discomfort to cause anxiety and depression in animals. Our daily lives exposes us to similar stressors, and over time, without adequate recovery time, this may lead to the development of anxiety and depression. One of the key factors in these stressors is the lack of hope given for conditions to improve. Often the animals are shown no obvious way out of their predicament, and this ultimately leads to feelings of hopelessness and despair. These feelings may be pivotal in the development of anxiety and depression.

anxiety and depression

The cause of anxiety and depression are not always obvious. However, stress is a major contributory factor in both conditions. Removing stress from our lives is a great way to treat anxiety and depression, but this is not always possible. Minimising any stress should however be possible for most people and should be considered a pivotal strategy in dealing with anxiety and depression.

It stands to reason, that if the cause of anxiety and depression is chronic exposure to stress, the best way to treat them would therefore be to remove the stress. However, this is not alway possible as many stresses are inbuilt into our modern life. Most people are not able to avoid work, commuting, relationships, family deaths and money troubles, and so for most it is not possible to completely remove stress from one’s life. Further, life is full of uncertainty, and it is often this uncertainty that contributes significantly to the development of anxiety and depression.

Certain individuals appear more susceptible to anxiety and depression compared to others, and this may be due to genetic differences. However, increasingly it is being shown in scientific studies that factors such as general health, physical fitness and diet may play a significant role in building a resistance to stress, which may ultimately delay or deter the development of mood disorders such as anxiety and depression. Of these, diet and strong social ties including links to family and friends, appear to be a particularly important factor in the resistance to stress.

What Drugs are Used to Treat Depression?

The standard therapy for depression has changed over time, but generally involves the use of pharmaceutical drugs. The main targets of these drugs are chemicals in the brain called neurotransmitters. In particular, targets for pharmaceutical drugs include three neurotransmitters called serotonin, noradrenaline and dopamine. These three neurotransmitters are all linked to the control of mood. The drugs used to treat depression usually target one of these neurotransmitters and aim to increase its levels in the brain. Their use is based on the premise that low levels of serotonin, noradrenaline or dopamine are the cause of depression. However, this is not proven, and other neurotransmitters are also likely involved.

anxiety depression

Pharmaceutical drugs are often seen as magic bullets. Allopathic medicine thinks of mood disorders like a jigsaw puzzle with a single missing piece. Western medicine aims to replace this single missing piece and in doing so return the person to health. However, mood disorders are highly complex and are more like a jigsaw puzzle with multiple missing pieces. Often a single solution does not exist.

One of the older class of antidepressant drugs is the tricyclic antidepressants. Drugs such as Amitriptyline, Clomipramine, and Imipramine fall into this class. These drugs work by blocking the reuptake of serotonin or noradrenaline, or both, to neurones.This increases the length of time these neurotransmitters are active in the brain, as reuptake reduces the active effects of neurotransmitters. The main disadvantage of these drugs is that they are associated with a certain amount of sedation at higher doses. Many herbs have been shown to be as effective as the tricyclic antidepressants in randomised placebo controlled trials, but without the debilitating side effects which can include dry mouth, postural hypotension (low blood pressure on standing), blurred vision and weight changes.

Another older class of antidepressant is the monoamine oxidase (MAO) inhibitors. Monoamine oxidase is an enzyme that breaks down the monoamine neurotransmitters serotonin, noradrenaline and dopamine. Monoamine oxidase inhibiting drugs include Isocarboxazid, Phenelzine, Tranylcypromine and Moclobemide. Again, many herbs have been shown to be as effective as MAO inhibitor drugs in direct comparison trials but without the common side effects of monoamine oxidase inhibitors, which can include dry mouth, insomnia, dizziness and nausea.

The most recent class of drugs used to treat depression are the selective serotonin reuptake inhibitors (SSRIs), noradrenaline reuptake inhibitors (NRIs) or dopamine reuptake inhibitors (DRIs). These drugs prevent the reuptake of serotonin, noradrenaline, or dopamine from the spaces between neurones, and in doing so they potentiate the effects of these neurotransmitters for longer. They are thought to be superior to the tricyclic antidepressant class of drugs because they are more specific, but have a similar mechanism of action.

The SSRIs, DRIs and NRIs appear to have some beneficial effects in some individuals, but they are not a miracle cure for depression. They may be more effective that the tricyclic antidepressants and monoamine oxidase inhibitors for most people. However, in some cases the use of SSRIs have been shown to worsen depression in certain individuals. Often the use of antidepressant drugs is guess work, with adjustments having to be made by the medical expert as treatment progresses. Again, herbal preparations have been directly compared to the reuptake inhibiting class of drugs and been shown to be as or more effective, with the added benefit of being far safer.

Another common drug used as antidepressants is the serotonin receptor specific antagonists such as Mirtazapine. These drugs work by increasing levels of serotonin and noradrenaline, through blockade of the serotonin receptor. Activation of this receptor normally causes a reduction in the release of serotonin and noradrenaline, and so by blocking it, serotonin and noradrenaline levels in the brain increase.

Another class of drugs used to treat depression are the melatonin agonists such as Agomelatine. These drugs work by improving the sleep wake cycle through the alteration of the circadian rhythms by interaction with melatonin receptors. In this way it has a similar effect to taking the supplement melatonin. The effects of the serotonin receptor specific agonists and melatonin agonists over the long term is not clear, and they are not the first choice of drug for most individuals suffering from depression.

anxiety and depression

The main classes of drugs used to treat depression are the tricyclic antidepressants, the monoamine oxidase enzyme inhibitors (MAO inhibitors), the selective serotonin reuptake inhibitors (SSRIs), the noradrenaline reuptake inhibitors (NRIs), the dopamine reuptake inhibitors (DRIs), the serotonin receptors specific antagonists and the melatonin antagonists.

What Drugs Are Used To Treat Anxiety?

Although depression is difficult to treat with drugs, anxiety may be even more so. Research investigating the treatment of anxiety shows that several neurotransmitter systems may be involved in the development of anxiety including both the serotonin and noradrenaline systems. However, with anxiety the neurotransmitter systems may be involved in the development of anxiety in a different way compared to depression. The excitatory neurotransmitter systems of the brain, particularly that of noradrenaline, may be overstimulated in those people with anxiety and treatment may required inhibition of the release of noradrenaline.

To control the excitatory noradrenaline systems and reduce its stimulatory effect, an inhibitory neurotransmitter system is normally activated in the brain. This system, the gamma aminobutyric acid (GABA) system, when activated can calm the neuronal activity in the brain by inhibiting the excitatory noradrenaline systems. This GABA system is the target of many of the anti-anxiety (anxiolytic) drugs including benzodiazepines and barbiturates.

The benzodiazepine (Diazepam, Oxazepam, Lorazepam) and barbiturate (Allobarbital, Barbital, Pentobarbital) classes of drugs both work by binding to the GABA receptors in the brain directly. This activates the GABA system, and this in turn inhibits the excitatory neurotransmitter systems of the brain, producing a calming effect. The barbiturate drugs have largely been superseded by the benzodiazepines. This is because the barbiturates are highly addictive, and it is much easy to overdose on them. However benzodiazepines are also considered quite dangerous, as they are also addictive, and coadministration with alcohol can be highly dangerous. Further, the use of benzodiazepine drugs is controversial because only about 25 to 30 % of individuals respond positively to their use.

As a result of the detrimental effects of taking benzodiazepines, many of those with mild to moderate anxiety choose to use natural alternatives that have a better safety record. Herbal remedies are often self medicated in this way, and many have been shown to have highly beneficial effects in the treatment of generalised anxiety disorder (GAD). Many herbs also work by binding to the GABA receptor in the brain, and in this way are very similar in their mode of action to benzodiazepines and barbiturates. Direct comparisons of herbs with these drugs show that herbs can be equally effective in direct comparisons, but carry much fewer adverse effects and are much safer.

The generalised anxiety disorder is increasingly being treated by use of the same selective serotonin reuptake inhibitors employed in depression. This may be partly explained by the fact that anxiety and depression often go hand in hand and in effect the drug is being used to treat the depressive aspect of the mood changes in the individual. The use of SSRI’s at treating anxiety is not fully understood, and this is reflected in the rather inconsistent performance of such treatment protocols. Some people seem to benefit from SSRIs, whereas they have no effect in others. As stated above this may be due to the co-presence of anxiety and depression in some individuals, with the SSRIs providing relief from depressive symptoms in those individuals experiencing both disorders.

anxiety and depression

The most commonly used drugs to treat anxiety are the benzodiazepines, the barbiturates, and the selective serotonin reuptake inhibitors (SSRIs).

Why are mood disorders so difficult to treat?

The aetiology (cause on development) of mood disorders is highly complex. The reason for this may be that anxiety and depression are caused by different things in different people, and people experience and describe changes to mood subjectively. Therefore anxiety and depression are not distinct disorders with black and white definitions, but are really disorders that span a broad scale, with each person experiencing their particular disorder subjectively.

The experience of anxiety and depression is therefore difficult to define unless each individual is taken on a case by case basis and time is taken to understand the individual concerns and symptoms of the individual. Despite the obvious variation in mood disorders between individuals, allopathic medicine likes to treat the mood disorders as identical conditions. In this regard allopathic medicine tries to treat anxiety or depression by targeting single or small groups of chemicals with specific and often single action drugs. However, this ‘one drug for one biochemical change’ approach is often not helpful and this is reflected in the relatively poor efficiency of allopathic medicine to treat mood disorders.

anxiety and depression

Mood disorders are highly complex. They often contain multiple components and this stems from multiple causes. Stress is a common underlying theme in the development of mood disorders, but even identifying the stressful event that was the trigger or cause of the disorder can be difficult. In some individuals, a single stressful event may trigger anxiety or depression. In others, chronic stress from multiple sources can be the cause, often spanning decades. In the case of the latter, this makes it incredibly hard to identify the causative factor, and this makes it difficult to eliminate it.

For example, the traditional allopathic view of depression is that it is caused by a deficiency of serotonin in the brain. Modern medical treatments as a result centre on the use of selective serotonin reuptake inhibitors (SSRIs). Studies however show that these drugs are really no more effective than placebo treatments for depression. In fact in many people SSRIs have negative effects and this can increase the likelihood of suicide or the development of worsening depression. Some people complain of feeling wired and detached from reality when on the SSRI drugs. If this is the case are the SSRIs really helping treat the depression or are they simply numbing the cognitive ability of that person so that the ability to think clearly and cogently is diminished?

Part of the reason for this lack of efficacy for the SSRIs may be that serotonin deficiency is not the cause of depression in many individuals, and the fixation on drugs to increase serotonin levels has been a short-sighted exercise in barking up the wrong tree. It also typifies the allopathic medical approach of using a sledgehammer to crack a nut. The brain is very complex and it is unlikely that a single ‘fault’ can explain the myriad of changes experienced in mood disorders.

anxiety and depression

Using a sledgehammer to crack a nut will crack the nut. But does it really achieve what is intended? Allopathic medicine often makes claims about the efficacy of modern medicine to treat mood disorders, but in a similar way, are the end goals really in the best interest of the patient?

More recently focus in medicine has changed somewhat. In this regard the lack of efficacy of the SSRIs lead to the development of the NRIs and the DRIs. These new drugs are based on the theory that in some individuals, a deficiency of noradrenaline, adrenaline and dopamine might be the cause of depression. This was in effect a tacit admission by allopathic medicine that their first attempt might not have been a good attempt. The involvement of noradrenaline and dopamine imbalances in the development of depression will not come as a surprise to those who have long suspected that depression may be caused by a widespread imbalance in a number of neurotransmitter systems. This imbalance may in turn be caused by prolonged stress and the hormonal changes that accompany it.

Drugs can help alleviate anxiety is some individuals, but generally their use for anxiety has been questioned because of inconsistent results. Drug treatments for anxiety such as barbiturates and benzodiazepines are best used on those with severe anxiety who are at risk of self harm or suicide. In this respect they are often used as a last resort to stabilising a deteriorating mood. Evidence does not suggest they are effective at actually reversing the low mood and returning the individual to health. It is more that the drugs are able to numb the cognitive ability of the individual, in effect sedating them to th the point of stupor. Often patients have to take the drugs chronically, often for decades. Also there are a number of known side effects including dependence, tolerance, withdrawal and cognitive impairment.

Because of the difficulty of treating mood disorders with drugs, in combination with their side effects, there is an interest in the use of nutrition to offer an alternative and effective treatment, with fewer of the inherent problems of using drugs. In this respect the nutritional approach to treating mood disorders is far more effective than the allopathic medical approach because it takes a holistic view and does not attempt to target a single neurotransmitter subgroup. Instead the focus is on improving general health, which is hoped will lead to optimisation of all neurotransmitter groups. Further there is an understanding that stress is an important component in the development of anxiety and depression, and as such, strategies to ameliorate the detrimental effects of stress are pivotal to the nutritional approach to treating anxiety and depression.

anxiety and depression

Mood disorders are highly complex. They often contain multiple components and this stems from multiple causes. Stress is a common underlying theme in the development of mood disorders, but even identifying the stressful event that was the trigger or cause of the disorder can be difficult. In some individuals, a single stressful event may trigger anxiety or depression. In others, chronic stress from multiple sources can be the cause, often spanning decades. In the case of the latter, this makes it incredibly hard to identify the causative factor, and this makes it difficult to eliminate it.

The nutritional approach to treating anxiety and depression is achieved using combination therapy which includes the use of high quality diets, isolated amino acid, herbs and phytochemicals alongside other proven mood enhancing strategies including exercise and meditation. The nutritional approach aims to produce a synergistic rebalancing within the brain. This rebalancing is different to the allopathic medical approach because it aims to allow natural healing through a rebalancing effect.

For example, exercise is perhaps the single most beneficial treatment for certain forms of mild depression. Not only is the physical activity useful, but the social aspect of performing exercise is highly underrated. The use of single amino acid treatments in nutritional therapies has centred on the use of L-tryptophan and its metabolite 5-hydroxytryptophan, as well as L-tyrosine. These amino acids are beneficial because they are used by the brain to manufacture serotonin and the the catecholamine neurotransmitters noradrenaline, adrenaline and dopamine. They are superior to drugs because they supply substrates for neurotransmitter synthesis before the rate limiting step in the synthesis pathway. In this way the brain’s own natural feedback inhibition is still able to prevent excessive production of single neurotransmitter types, something which a drug treatments often bypass. High quality diets improve health generally and as physical health improves mental health often concomitantly follows. Meditation is effective at treating anxiety and depression because it offers a way for the individual to limit the detrimental effects of stress and this then allows the healing process to begin.

However, perhaps the most promising aspect of nutrition for the treatment of mood disorders is the use of herbal treatments. Often these treatments have been used historically in traditional medicine such as Traditional Chinese Medicine, Greco-Arabic Unani Traditional Medicine or Ayurvedic medicine. Their effects in such medical systems is well documented, but modern medicine has been slow to acknowledge the beneficial effects of these herbal treatments.

anxiety and depression

Mood disorders are an increasing burden on health care systems, with pharmaceutical drugs being the treatment of choice. But are pharmaceutical drugs the best option when trying to treat complex mood disorders? Evidence suggest that herbal medicine may offer a better solution for long term health in cases of mild to moderate depression and anxiety.

In many cases, modern allopathic medicine still considers such treatments as ineffective and worthless, despite voluminous scientific evidence to the contrary. However, modern science has shown many herbs to be highly effective in the treatment of mood disorders. In fact, direct comparisons of herbal treatments with the best drugs currently on offer to allopathic medicine shows that the herbal treatments are often as, or more effective than drugs, but possess none of the adverse effects associated with the drugs. This makes them excellent options for long term use and excellent choices for self medication in cases of mild to moderate anxiety or depression.

In fact, the wide availability of the herbs, in combination with their excellent safety records and their proven biochemical and physiological effects means they are increasingly being used by individuals to self medicate in the treatment of mood disorders. What started as a trickle has now become a flood, as more people turn to safer and more natural alternatives to the sledgehammer approach of allopathic medicine.

The effects of the herbal treatments stem from the presence of particular phytochemicals (plant chemicals) within the herbs. In many cases these phytochemicals have been identified and isolated, and their effects in animals and humans documented. Herbs often contain multiple classes of phytochemicals, with each phytochemical group possessing a different biochemical effect. This provides a wide ranging and more delicate treatment effect compared to a single action drug, and this explains not only the beneficial effects but the lack of side effects inherent with herbal treatments. Nature has therefore provided a cornucopia of medicinally active and safe compounds in plants that can be used to treat mood disorders. In the following sections of this book, some of these herbs and the phytochemicals they contain will be discussed and their beneficial uses at treating mood disorders explored.


American Psychiatric Association. 2013. Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC.
Bijl, R. V., Ravelli, A. and van Zessen, G. 1998. Prevalence of psychiatric disorder in the general population: results of the Netherlands Mental Health Survey and Incidence Study (NEMESIS). Social Psychiatry and Psychiatric Epidemiology. 33(12): 587–595
Doghramji, K. 2006. The epidemiology and diagnosis of insomnia. American Journal of Managed Care. 12(8): S214-S220
Gotlib, I. H., Whiffen, V. E., Mount, J. H., Kenneth, M. and Cordy, N. I. 1989. Prevalence rates and demographic characteristics associated with depression in pregnancy and the postpartum. Journal of Consulting and Clinical Psychology. 57(2): 269-274
Grigsby, A. B., Anderson, R. J., Freeland, K. E., Clouse, R. E. and Lustman, P. J. 2002. Prevalence of anxiety in adults with diabetes: a systematic review. Journal of Psychosomatic Research. 53(6): 1053-1060
Kessler, R. C., Ruscio, A. M., Shear, K. and Wittchen, H. U. 2010. Epidemiology of anxiety disorders. Current Topics
In Behavioural Neuroscience. 2: 21-35
Lepine, J. 2002. The epidemiology of anxiety disorders: Prevalence and societal costs. Journal of Clinical Psychiatry. 63(14): 4-8
Massie, M. J. 2004. Prevalence of depression in patients with cancer. Journal of the National Cancer Institute Monographs. 32: 57-71
Mendlowicz, M. V. and Stein, M. B. 2000. Quality of life in individuals with anxiety disorders. American Journal of Psychiatry. 157(5): 669–682
Riolo, S. A., Nguyen, T. A., Greden, J. F. and King, C. A. 2005. Prevalence of depression by race/ethnicity: findings from the National Health and Nutritional Examination Survey III. American Journal of Public Health. 95(6): 998-1000
Spiker, J., de Graaf, R., Bijl, R. V., Artjan, A., Beekman, T. F., Ormel, J. and Nolen, W. A. 2002. Duration of major depressive episodes in the Duration of major depressive episodes in the general population: results from The Netherlands Mental Health Survey and Incidence Study (NEMESIS). British Journal of Psychiatry. 181: 208-213