The basics - Depression

In most patients an underlying cause is not found, writes Dr Louise Newson.

Depression is a very common disorder in primary care and is still often underdiagnosed. A study by the WHO ranked depression the fourth leading global burden of disease and found it to be the largest non-fatal burden of disease.1

Depressive disorders are characterised by persistent low mood, loss of interest and enjoyment and reduced energy. This often impairs day-to-day functioning. Depression is more common in people aged 20-50 years, although 10 per cent of patients with depression have onset after the age of 60 years.

Depression probably affects as many men as women but in the elderly it is more prevalent in women

Depression has previously been thought of as much more common in women, but it is now considered that men are probably equally affected but less commonly diagnosed and treated. However, depression is more prevalent in elderly women than men (> 70 years).

NICE guidance on depression gives recommendations for the identification, treatment and management of depression for adults in both primary and secondary care.2

Aetiology
For most patients with depression, the underlying cause is not clearly established. For approximately 25 per cent of patients, their depression is associated with a precipitating event.

Depression is also more common in those with a chronic illness (for example, diabetes or cardiovascular disease).

The cause of depression is unknown but it seems to result from a complex interaction between external and internal stresses, genetic factors and biochemical changes in the brain.

There is no clear relationship between the apparent cause of the depression and the subsequent response to antidepressant drug treatment.

Screening
It is recommended that screening should be undertaken for depression in high-risk groups. These include patients with a past history of depression, significant physical illnesses causing disability or other mental health problems, such as dementia.

The QOF recommends that patients with diabetes and CHD are screened for depression. For this, NICE recommends that the following two questions should be used:

  • During the past month, have you been feeling down, depressed or hopeless?
  • During the past month, have you often been bothered by having little interest or pleasure in doing things?

Criteria for diagnosis
NICE recommends that the ICD-10 (International classification of mental and behavioural disorders) criteria are used for diagnosing and assessing the severity of depression (see box).

ICD-10 criteria for diagnosis of depression

Typical symptoms:

  • Depressed mood
  • Loss of interest and enjoyment
  • Increased fatigability

Common symptoms:

  • Reduced concentration and attention
  • Reduced self-esteem and self-confidence
  • Ideas of guilt and unworthiness
  • Bleak and pessimistic views of future
  • Ideas or acts of self-harm or suicide
  • Disturbed sleep
  • Diminished appetite

Symptoms should be present for a month or more and every symptom should be present for most of every day.

Not depressed (<4 symptoms), mild depression (4 symptoms), moderate depression (5-6 symptoms), and severe depression ([s40]7 symptoms, with or without psychotic symptoms).

Assessment of depression
There are three tools recommended to assess newly diagnosed patients. They each only take a few minutes to complete:the Patient Health Questionnaire (PHQ-9); the Hospital Anxiety and Depression Scale (HADS); and the Beck Depression Inventory, Second Edition (BDI-II).

The HADS and PHQ-9 have demonstrated reliability, validity and responsiveness to change in one study.3 However, they differed considerably in how they categorised severity of depression, which may then have implications for the treatment given.

Another study has shown that brief self-rated questionnaires are as good as clinician-administered instruments in detecting depression in primary care.

Management
The psychological, social, cultural and physical characteristics of the patient and the quality of interpersonal relationships should be considered when assessing the patient. These may affect the choice of treatment.

Mild depression
'Watchful waiting' may be beneficial for patients with mild depression who do not want an intervention. They should be reassessed within two weeks.

Advise about sleep hygiene, anxiety management and regular structured exercise.

A guided self-help programme could be considered based on cognitive behavioural therapy (CBT) or a brief psychological treatment (such as problem-solving therapy, brief CBT or counselling).

Antidepressants are not recommended for initial management of mild depression, but could be considered for patients with mild depression persisting after other interventions; patients whose depression is associated with psychosocial and/or medical problems or patients with a past history of moderate or severe depression.

Moderate-to-severe depression
Antidepressants should be offered as first-line treatment for moderate-to-severe depression. SSRIs should generally be considered first line.

Fluoxetine and citalopram are first choice. Sertraline should be used in those who have had a recent MI or have unstable angina. Discontinuation symptoms are more frequent with paroxetine. Venlafaxine can now be prescribed in primary care as a second-line treatment.

Psychological treatments should be offered to patients who do not want to take antidepressants.

Severe depression
In severe depression, a combination of antidepressant and a psychological intervention should be considered as the combination is more effective than individual treatments. ECT may be necessary for some patients.

Antidepressants
All patients who are prescribed antidepressants should be informed of potential side-effects and of the risk of discontinuation/withdrawal symptoms. They should also be informed about the delay in onset of effect and the need to take medication as prescribed.

Patients started on antidepressants who are not considered to be at increased risk of suicide should normally be seen after two weeks. Thereafter they should be seen regularly, for example, at intervals of two to four weeks in the first three months and at longer intervals thereafter.

Antidepressants should be continued for at least six months after remission of an episode of depression, because this greatly reduces the risk of relapse.

It is generally recommended that the dosage of antidepressant is gradually reduced over a four-week period, although some patients may require longer periods. Fluoxetine can usually be stopped over a shorter period due to its shorter half-life.

St John's wort
Although there is evidence that St John's wort may be beneficial, the advice is not to prescribe it or advise its use. There is still uncertainty about the appropriate dosages, variation in the nature of preparations and potential serious interactions with other drugs (including oral contraceptives, anticoagulants and anticonvulsants).

Computerised CBT
NICE recommends the use of computerised CBT to treat depression and anxiety. 'Beating the Blues' is for patients with mild and moderate depression. 'FearFighter' is for patients with panic and phobia.

Prognosis
The outlook for a patient with depression often depends on the severity of the depression. Studies have shown those with poorer prognosis include men, those with dysthymia, substance abuse, a past history of depression or anxiety and also the elderly.

  • Dr Newson is a GP in Solihull, West Midlands
  • Depression Awareness Week runs from 20 April. For more information visit www.depressionalliance.org

References

1. Ustun T B, Ayuso-Mateos J L, Chatterji S et al. Global burden of depressive disorders in the year 2000. Br J Psychiatry 2004; 184: 386-92.

2. NICE Guidance. Depression (Amended) April 2007.

3. Cameron I M, Crawford J R, Lawton K, Reid I C. Psychometric comparison of PHQ-9 and HADS for measuring depression severity in primary care. Br J Gen Pract 2008; 58: 32-6.

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