1. Aetiology, epidemiology and clinical features
Depression is estimated to affect between 5 and 10 per cent of the general population. It is associated with an increased risk of suicide and the risk of illnesses such as heart disease, diabetes and stroke.
It is more frequent in women during the reproductive years but, after the age of 55, the sex ratio equalises. At least 50 per cent of people who have an episode of major depression will go on to have at least one further episode. Those experiencing early-onset depression (aged 20 or below) are particularly vulnerable to recurrence.
Depression can present with a wide range of symptoms. It may be difficult to distinguish depressive illness from normal sadness.
An important distinction is that symptoms must be present for at least two weeks to make a diagnosis.
Commonly, somatic symptoms are the main complaint of depressed patients. These include headache, abdominal pain and musculoskeletal pains. Depression is also associated with symptoms such as a change in appetite and lack of energy. Other psychological symptoms include feelings of worthlessness or excessive guilt and, in some cases, suicidal thoughts. Most patients present with a combination of both psychological and somatic symptoms.
NICE issued guidelines on the treatment and care of people with depression in December 2004, based on a stepped-care model (see below).
Five-step care model from NICE
- Recognition of depression.
- Managing recognised depression in primary care — mild depression.
- Managing recognised depression in primary care — moderate to severe depression.
- Involvement of specialist mental health services including crisis teams — treatment-resistant, recurrent, atypical and psychotic depression, and those at significant risk.
- Depression needing inpatient care.
Of the 130 cases of depression per 1,000 of the population, only 80 will consult their family doctor.
Even when depressed patients do present to a GP, they may not be correctly diagnosed.
Of those who do seek advice, over half are not diagnosed with depression. This is mainly because most patients present with physical symptoms and do not consider themselves to be mentally unwell.
The highest detection rates are from GPs who have an accurate concept of psychiatric disorders.
GPs with an empathetic interviewing technique and who are sensitive to emotional cues are also more likely to diagnose depression promptly.
Screening for depression
NICE recommends screening in high-risk groups. Screening should include the use of at least two questions concerning mood and interest, such as ‘During the last month, have you often been bothered by feeling down, depressed or hopeless?’ and ‘During the last month, have you often been bothered by having little interest or pleasure in doing things?’
The quality framework rewards practices for screening among patients with diabetes and coronary heart disease.
The International Classification of Diseases (ICD-10) criteria can help diagnosis and assess severity. There are 10 symptoms (see below).
Symptoms should be present for at least two weeks. Every symptom should be present almost every day. If there are four symptoms present, this suggests the depression is mild. Five or six symptoms represent moderate depression, and seven or more — with or without psychotic symptoms — suggest severe depression.
Criteria for diagnosis of depression
- Low mood.
- Loss of interest/enjoyment.
- Disturbed sleep.
- Reduced appetite/weight loss.
- Reduced energy/fatigue.
- Reduced concentration/attention.
- Ideas of guilt/low self-worth.
- Thoughts of self-harm.
- Reduced self-esteem/confidence.
3. Treatment options
The main treatment options are pharmacotherapy and psychological therapies such as cognitive behavioural therapy (CBT) and counselling.
NICE guidance recommends problem-solving therapy, brief CBT and counselling in mild and moderate depression. In moderate, severe and treatment-resistant cases, the treatment of choice is CBT. The recently published Layard report has recommended that availability of CBT be increased significantly and pilot projects evaluating increased provision were commenced in 2006.
Antidepressants should not be used for the initial treatment of mild depression, but should be routinely offered to all patients with moderate depression. Compliance is helped by telling the patient about the delay in onset of effect, potential side-effects and the duration of treatment.
Patients without increased suicide risk should be reviewed two weeks after starting treatment. Treatment should continue for at least six months after remission.
SSRIs should be used routinely in primary care — they are as effective as tricyclic antidepressants but less likely to be stopped due to side-effects. If a patient develops agitation, consider switching to an alternative, or add a benzodiazepine with a review in two weeks. Avoid long-term use of benzodiazepines because of their potential for dependence. If the response is inadequate and there are no significant side-effects, gradually increase the dose according to the summary of product characteristics.
If there has been no response after a month, consider a different SSRI or mirtazapine. Other issues to consider are the patient’s sex, age and co-existing health problems.
Many patients with milder depression respond to advice on sleep hygiene and anxiety management with a period of ‘watchful waiting’.
The patient should be reviewed after about two weeks. A structured exercise programme over 10–12 weeks and a guided self-help programme based on CBT can help. Problem solving, brief CBT or counselling sessions for 10–12 weeks should be considered for all ages.
Moderate to severe depression
can be treated in primary care; antidepressants should be routinely offered. A programme of 16–20 structured psychological interventions is effective.
CBT is the treatment of choice for moderate, severe and treatment-resistant depression, for patients who refuse drugs, or those who have not responded to other treatments.
Antidepressants and suicide
The MHRA Expert Working Group concluded that, for a small number of people, there may be an increase in suicidal thoughts and behaviour with all antidepressant treatment, including SSRIs. Patients thought to have an increased suicide risk, or those under 30, should be seen after a week and then at regular intervals until the risk is no longer significant.
Factors that make it appropriate to refer patients include a poor or incomplete response to treatment (defined as failure to respond to two or more antidepressants given sequentially), a relapse within one year of a previous episode, a specific request from the patient or relatives and self-neglect.
Consider urgent referral in patients with active suicidal plans and psychotic symptoms accompanying more than 10 symptoms. Inpatient treatment should be considered for people who are severely depressed.
New advances in treatment
Complete remission is increasingly recognised as the optimal outcome of the acute phase of antidepressant therapy. However, only about one patient treated in three achieves this goal.
Treating a broader range of depressive symptoms may result in more patients achieving full remission.