What is depression?

Although depression is a very common condition, with lifetime prevalence as high as 17% in the western world, it is both under-recognised and under-treated. Approximately two thirds of people with depression may never be appropriately diagnosed and properly treated, either because they fail to seek medical care or because their symptoms are misdiagnosed.

Key facts

Depression – a global disease

What is depression?

Who suffers from depression?

What are the symptoms?

The causes of depression

The economic burden of depression

Management of depression

Therapeutic options in depression

References

 

Key Facts:

• Depression is a common illness that affects one in every five women and one in every ten men during their lifetimes.
• According to the WHO, depression is today a leading cause of disability globally.
• Depression is a major cause of suicide.
• Depression is under-diagnosed and under-treated.
• People with depression are less likely to comply with their treatment regimen compared to other patient groups.
• SSRIs offer both good tolerability and efficacy in the treatment of depression.
• Cipralex, the Serotonin Dual Action antidepressant with fast onset of action offers superior efficacy and good tolerability.

Depression – a global disease

Clinical depression should not be confused with the occasional bout of the 'blues' that everyone experiences from time to time. Depression is a recognised mental disorder with quantifiable symptoms that often have a serious impact on the person's quality of life, physical well-being and productivity in society.

As the incidence of depression rises, it is on the verge of becoming globally one of the most debilitating diseases this century. According to the World Health Organisation (WHO), major depression (i.e. severe depressed mood that is episodic in nature and recurs in 75-80 per cent of cases) is now the leading cause of disability world-wide with a lifetime prevalence of 17 per cent in the western world (ref.1), thus ranking fourth among the ten leading causes of global disease burden (ref.4). In addition, the WHO states that depression is the most common mental disorder leading to suicide and they project that, at its present rate of growth, depression will be the second leading contributor to global disease burden by 2020.

Most cases of depression are treated in the primary care setting by general practitioners (ref.4, ref.5). However, poor treatment duration or poor compliance have led to the illness being under-recognised as well as under-treated. Only 33 per cent of those who suffer from clinical depression during their lives will receive effective treatment (ref.2).

Clearly, these statistics call for greater awareness of depression among healthcare professionals, patients and their families or carers. This is why organisations like the WHO are dedicating awareness weeks and campaigns to highlight the problem and to improve the standard of treatment for patients.

What is depression?

Clinical depression is a mental condition in which patients the individual suffers from an intense change in mood, which is often disproportionate to events occurring in their lives. The change in mood can present itself as 'sadness' in the patient, but may also involve other emotions, such as restlessness, agitation, lack of energy or a feeling of emptiness. Patients People suffering from depression experience these feelings persistently -: usually, though not always, following a stressful event.

Who suffers from depression?

People of all ages, gender and race can suffer from depression, although it is more common in adult women. Women are, however, more likely to seek treatment for depression and are twice as likely as men to be treated for the condition. The gender difference in treatment rates tends to disappear in the elderly (ref.4) while the elderly continue to be at high risk of depression, the average age of onset is becoming increasingly younger (ref.6).

What are the symptoms?

The symptoms of depression impact upon patients both mentally and physically, typically preventing sufferers from leading normal lives. Symptoms may be chronic or recurrent, depending on the type of depression and, in severe cases, can lead to suicide. Symptoms may include any, or a combination of, the following: (ref.3)

• Lowered mood / sadness
• Lack of energy / fatigue
• Reduced enjoyment in previously pleasurable activities
  Loss of sexual interest
• Interrupted sleep patterns, insomnia, oversleeping, early morning waking
• Loss of appetite or over-eating
• Lack of self-esteem
• Irritability / lack of concentration
• Persistent headaches or other pains that do not respond to treatment
• Thoughts of death or suicide attempts

The causes of depression

The causes of depression are not yet fully understood, with each case usually involving a number of contributing factors. However, an imbalance in the levels of chemical messengers (neurotransmitters) in the brain is implicated. Neurotransmitters, for example serotonin, carry messages from one cell to another in the brain. Many antidepressant drugs increase the level of brain neurotransmitters, such as serotonin.

Depression can occur independently, or be triggered by stressful or emotional situations (e.g. bereavement, loss of a job or severe illness), with the initial reaction to these events persisting and developing into prolonged depression.3 Depression can also be associated with specific chronic conditions, such as Alzheimer's disease, Parkinson's disease, heart disease, stroke, cancer and AIDS. (ref.2, ref.3, ref.4).

Diseases that impair quality of life may also lead to depression (ref.4). A WHO study showed that people with persistent pain were over four times more likely to have depressive disorder than those without pain (ref.7). Furthermore, depression in the elderly is often associated with diseases that significantly reduce quality of life, like arthritis (ref.8, ref.9).

Physiological factors like hormonal changes can also lead to depression. Fluctuating hormonal levels that occur during pre-menstruation, pregnancy or while taking oral contraception may explain the higher incidence of depression in women (ref.10).

Research is also pointing to a genetic basis that may increase the likelihood of an individual developing depression, (ref.3) although people with no family history of the disease also experience depression. 

The economic burden of depression

In addition to the severe clinical symptoms that depression imposes on the individual, the economic costs to society are extensive. People suffering from depression use 50-100 per cent more health care resources than people who are not depressed (ref.11, ref.12, ref.13). In the early 1990s, it was estimated that treating people with depression in England and Wales cost the NHS £417 million, with only 11 per cent of this accounting for the cost of drugs (ref.14). The direct costs of depression in the United States (e.g. the costs of drugs, hospitalisation and psychiatric therapy) have been estimated at $2.1 billion. (ref.15)

Medication costs form a relatively small part of the total direct costs of depression, with hospital admissions and healthcare services making up the bulk of the costs (ref.14). However treatment failure caused by patient non-compliance, in part due to the adverse effects of some medications, has a significant impact on depression costs. In addition, inadequate duration of therapy - i.e. patients who stop taking their medication too early - also contributes to this economic burden (ref.15).

Conversely; optimal antidepressant therapy reduces both the direct and indirect costs of depression. A good tolerability profile, in addition to efficacy, is a key factor in successful therapies, as it encourages people to keep taking their medication as prescribed. Effective and tolerable antidepressants help to improve compliance, thereby minimising the risk of relapse and reducing the overall economic depression burden.

However direct costs are only the tip of the iceberg, as much of the high cost of depression is due to the indirect costs of the disease, such as lost productivity and loss of time from work (ref.15) US economists have estimated that these indirect costs, which result from the impact of depression on person's ability to function in their usual role, reach an astonishing $14.2 billion (ref.15).

Management of depression

Not only is depression under-diagnosed and under-treated (ref.17), but studies have shown that people with depression are less likely to comply with taking medication than other patient groups (ref.4, ref.16). Many people stop taking antidepressants too soon, partly because of side effects of some drugs, which can lead to a relapse of the depressive symptoms, (ref.18) while others stop taking their medication too soon because they "feel better." As one doctor who suffers from depression explains:

“Every time you take an antidepressant, it is a reminder that you are "weird", that your thought patterns are abnormal, and that to function normally you depend on medication. Because you are desperate to seize any hope that you have returned to 'normal' is it any surprise that medication is stopped sooner than recommended?” (ref.19).

As a direct result of depression, patients tend to be trapped in a downward spiral that exacerbates the condition. For instance, fatigue, deteriorating sexual relations and the social stigma associated with depression can all lead to worsening of the depression. Therefore, it is essential that clinical depression is identified as quickly as possible and that appropriate treatment is administered.

Therapeutic options in depression

Depression can be effectively controlled in 40-80 per cent of people with medication, psychotherapy, or a combination of the two (ref.2). Psychotherapy concentrates on developing the individual's self-understanding and addressing events in their life that may contribute to the depression.

Antidepressant drugs are generally effective for approximately three in every five people with depression (ref.20). Although it is not absolutely clear exactly why they have a positive effect on the condition, many antidepressants work by increasing levels of neurotransmitters in brain synapses.

Two classes of antidepressants have been used for more than 30 years - the tricyclics (TCAs) and the monoamine oxidase inhibitors (MAOIs). However, the discovery in the 1980's that increasing the level of serotonin at brain synapses relieves symptoms of depression led to the development of a new class of drugs - serotonin re-uptake inhibitors (SSRIs) that selectively block the re-uptake of serotonin. Although SSRIs provide equivalent efficacy levels compared to TCAs, MAOIs they have demonstrated much improved safety and tolerability and are the first line treatment recommended today. Mostly as second line treatment serotonin and noradrenalin re-uptake inhibitors (SNRIs) are in use. SNRIs non-selectively increase brain levels of noradrenalin and serotonin using various mechanisms, but are often less well tolerated than SSRI.

Tolerability is a particular issue among people with depression, as adverse side effects can cause patients to discontinue their course of treatment and relapse into depression. SSRIs are also safer in overdose, (ref.2) which is particularly relevant given that people with depression typically experience suicidal thoughts and 15-20 per cent go on to commit suicide (ref.4). Suicide remains one of the common and avoidable outcomes of depression.

The introduction of Cipralex, a new powerful antidepressant, is the latest development in antidepressant therapy. Cipralex, the active S-enantiomer of citalopram, offers greater efficacy and faster onset of action than its predecessor, but with the same excellent tolerability. It also shows a low potential for interacting with other drugs, which is an important consideration when treating depressed patients with co-morbid conditions, like the elderly (for further information see Cipralex backgrounder).

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References:

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