In 2000, a WHO study concluded that depression was the top non-fatal disease and the fourth ranked disease overall globally.
Prevalence has increased in patients with a chronic physical disease to 5 to 10 per cent in primary care and up to 14 per cent in those requiring secondary care input for their condition.
Research has shown that up to 90 per cent of patients with chronic diseases such as COPD have depression.
1. Diagnosis and screening
Diagnosis is not always straightforward. Studies have demonstrated that 50 to 70 per cent of patients fail to have their depression diagnosed in primary care. It is thought that this is in part due to the majority of cases presenting with primarily somatic rather than cognitive or biological features of depression. This may reflect the stigma of depression and patients' unwillingness to be honest about their mental state.
In addition to clinicians tailoring consultations to account for somatisation, screening for depression, particularly in those with chronic diseases may further improve yield and this is reflected in the chronic disease domains of the QOF.
Furthermore, one should not discount that treating the underlying chronic disease may have a positive cognitive impact.
The possibility of a physical disease masquerading as depression should be considered and hypercalcaemia, thyroid disease, diabetes, dementia are a few conditions which, when treated, may resolve the patient's mood disturbance.
Screening questions for depression as recommended in NICE guidance are:
- During the last month, have you often been bothered by:
- Feeling down, depressed or hopeless?
- Having little interest or pleasure in doing things?
2. Risk assessment
Once depression has been diagnosed, risk assessment and disease severity should be considered before a management strategy is formulated. Risk assessment influences whether the patient requires immediate assessment or admission to an acute facility. Reasons for this are usually suicidal or homicidal risk, or indeed psychosis.
The welfare of the patient's dependants should also be considered. A history of failed suicide and self-harm and co-existing mental health problems, such as alcohol and drug abuse, anxiety and obsessive-compulsive disorder, should be explored.
The affect in depression tends to be mood congruent and auditory hallucinations are usually in the second person. This is in contrast to schizophrenia, where mood incongruency and auditory hallucinations tend to be in the third person.
When appropriate, the patient should be probed for the presence of delusions. Delusional systems often have religious qualities. Paranoid and nihilistic delusions are not uncommon in severe depression.
Assessment of disease severity is required in order to aid initial and ongoing management. Ultimately this is done using clinical judgment although questionnaires are used to objectively quantify severity and assess response to treatment. A clear understanding of the effect of depression on the patient's day-to-day life and ability to function is crucial.
3. Stepped care
NICE describes a 'stepped care' model which clearly defines treatment strategies according to disease severity. Disease severity is classified by NICE according to DSM-IV. The management of depression must, where possible, be shared and agreed by doctor and patient to ensure maximum adherence.
The patient's experience of previous treatments should be understood by the clinician as this often influences further treatment decisions. There will be instances where extreme symptoms require a more paternalistic approach.
In addition sleep hygiene and exercise should be encouraged in conjunction with advice regarding smoking and alcohol.
Low intensity psychological interventions have been advocated in sub-threshold, mild and moderate depression. These include problem solving therapy, counselling, cognitive behavioural therapy (CBT) and computerised CBT, which has a good evidence base. Marital therapy may also be appropriate.
4. Pharmacological treatment
Pharmacological treatment should not be used for sub-threshold or mild disease unless this is pervasive or associated with physical illness, psychological interventions have failed or the patient has a past history of at least moderate disease.
Uncomplicated patients who initially present with moderate severity may be tried on high-intensity psychological treatment prior to antidepressants.
SSRIs are the drug of choice and are the safest antidepressants in overdose. Sertraline is advocated in patients who have recently had an MI. Venlafaxine poses a greater risk in overdose than SSRIs, and tricyclic antidepressants confer the greatest risk. MAOIs should only be prescribed in secondary care.
Patients should be reviewed one to two weeks after commencement of antidepressants depending on disease severity. If the initial antidepressant fails to work or needs to be changed for another reason, it can be swapped with the help of tables found in MIMS.
Antidepressants should be continued for six months after recovery to reduce risk of relapse. Except for fluoxetine, most antidepressants may be reduced over a four-week period, although drugs with a shorter half-life such as venlafaxine require a longer tailing off period.
- Dr Thakkar is a GP in Wooburn Green, Buckinghamshire
- NICE. Depression. The treatment and management of depression in adults. CG90. London, NICE, 2009. http://guidance.nice.org.uk/CG90
- Timonen M, Liukkonen T. Management of depression in adults. BMJ 2008; 336: 455-9.