Masterclass: A complete GP's guide to depression

In the next of our Masterclass series, mental health specialist GP Dr Peter Bagshaw explains the latest knowledge and best practices in the treatment of depression in primary care. This series features content from our Pulse reference site, which helps GPs make diagnoses. We are expanding this service to include advice on the management and treatment of conditions.

Definition/diagnostic criteria

Depression is characterized by persistent feelings of sadness, worthlessness, loss of interest or pleasure in activities, and changes in sleep, appetite, or energy levels.

In the WHO International Classification of Diseases 11th Revision (ICD-11), depression is defined as:

‘The presence of depressed mood or decreased interest in activities that occur most of the day, almost every day, for at least two weeks, accompanied by other symptoms such as reduced ability to concentrate, low self-esteem or inappropriate guilt, hopelessness about the future, recurrent thoughts of death or suicidal ideation, significantly interrupted or excessive sleep, significant changes in appetite, psychomotor agitation or retardation, and reduced energy or fatigue.‘

Traditionally, depression is divided into four subgroups: subthreshold, mild, moderate and severe. However NICE describes less severe depressiondefined as depression with a score of less than 16 on the Patient Health Questionnaire (PHQ-9) scale, more severe depression score of 16 or more, chronic depressive symptoms and psychotic depression. Bipolar disorder is treated separately, here and in NICE guideline on depression in adults (NG222).

Epidemiology

Depression affects around 1 in 10 people in the UK, and around 1 in 4 over 65s (of whom an estimated 85% are untreated). It can occur at any age and is more common in women. Risk factors include personality, genetic predisposition, pregnancy and childbirth, menopause, loneliness, coexisting diseases, alcohol and drug dependence.

Diagnosis

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Patients generally present with the symptoms described above, although older people often present with physical symptoms or delusions rather than describing a low mood. PHQ-9 is the standard scale for rating severity and patients should always be asked about suicidal ideation.

The differential diagnosis is broad and may include:

Diseases of the central nervous systemfor example, Parkinson’s disease, dementia, multiple sclerosis.
Endocrine disordersfor example, hyperthyroidism, hypothyroidism.
Drug-related conditionsfor example, cocaine abuse, side effects of some CNS depressants.
infectious diseasefor example, infectious mononucleosis.
Sleep-related disorders.
Other psychiatric disorders for example, personality disorder, dysthymia, bipolar disorder.

Investigations may be helpful to exclude other conditions, such as thyroid disease. Focal neurological symptoms or signs are not characteristic of depression and, if found, should prompt urgent neurological referral.

Treatment

Treatment of depression involves a combination of approaches tailored to the patient’s individual needs. Exercise, meditation, mindfulness and guided self-help are beneficial and may be all that is required in mild depression. In less severe depression, talk therapies such as cognitive-behavioral therapy, interpersonal psychotherapy or short-term psychodynamic psychotherapy are recommended. NICE states:

‘Do not routinely offer antidepressants as first-line treatment, unless that is the person’s preference. If the person has a clear preference or experience of previous treatments to use as a guide: support the person’s choice, unless there are concerns about suitability for this episode of depression.’

In more severe depression, a similar set of therapies is recommended, and the most appropriate options are arrived at after discussion with the patient. Individual cognitive behavioral therapy plus an antidepressant is recommended as the most clinical and cost-effective option. If there is no response within 4 to 6 weeks, shared decision making should be used to consider switching to an alternative drug or talk therapy.

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If the medication is considered appropriate, it is advisable to review how well the treatment is working for the person between 2 and 4 weeks after starting it, or after 1 week if it is a new prescription for a person under 25 years of age, or if there is a particular concern about the risk of suicide. We should monitor treatment concordance, side effects and harms, and suicidal ideation, particularly in the first weeks of treatment.

Patients starting medication should receive appropriate written advice, including knowing who to contact if their symptoms worsen, and should always be warned about the risk of side effects from withdrawal, which should usually be done by tapering the medication gradually. instead of stopping it abruptly.

NICE does not make specific recommendations on which antidepressants to use, although it notes that a longer half-life reduces the risk of withdrawal effects. For most, the first option would be an SSRI, and the next option would be an SNRI. Tricyclic antidepressants and monoamine oxidase inhibitors are rarely used due to side effects or safety profile in overdose.

In older people, the only antidepressants recommended are sertraline or, if sedation is helpful, mirtazapine (a specific norepinephrine and serotonergic antidepressant). Tricyclics should never be used in this group (including low-dose amitriptyline) due to sedation, cardiac risks, and anticholinergic burden.

Referral to a crisis team is recommended for people with more severe depression who are at significant risk of suicide, self-harm or harm to others, self-neglect, or complications in response to their treatment, for example, older people with medical comorbidities.

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Treatment-resistant depression is a rapidly evolving area, with early-stage research underway with psilocybin, LSD, ketamine, and other controversial agents. NICE supports electroconvulsive therapy, transcranial magnetic stimulation and vagus nerve stimulation in selected cases, and specifically advises against the use of St John’s wort.

Forecast

In younger people, untreated depression will remit spontaneously in more than half of cases within 12 months. Overall remission with treatment is around 70%-90%, and early recognition and intervention are associated with better outcomes. However, there is a lifetime risk of recurrence of 60% after the first major depressive episode, 70% with two episodes, and 90% in those with three or more episodes.

Additionally, people suffering from a depressive disorder have a risk of suicide 30 times higher than the general population, and approximately 15% of patients suffering from a depressive disorder make at least one suicide attempt.

Written by Dr Peter Bagshaw, GP and Clinical Lead for Mental Health and Dementia at NHS Somerset CCG