Churchill is famously rumoured to have described his depression as a ‘black dog’. It is a very common condition and has a prevalence in the UK of around 4.5 percent. You will almost certainly come across cases while on GP and psychiatric placements. In this quiz we test your understanding of the diagnosis, differentials and management for patients experiencing low mood. At the bottom of the page we also provide a summary of some of the key points about the diagnostic criteria for depression, its management, and the difference between ICD-10 and ICD-11.

Reviewed by: awaiting review


Congratulations - you have completed Depression. You scored %%SCORE%% out of %%TOTAL%%. Your performance has been rated as %%RATING%%
Your answers are highlighted below.
Question 1

Stem 1 - Question 1

You are an FY2 on your GP placement. A 28 year old woman comes to see you complaining of lethargy and a low mood for the past three weeks. She has been off her food and been struggling to follow her favourite soaps on TV. She denies any thoughts of self-harm or suicide. She lost her job a few months ago due to redundancy and hasn’t been able to find something since despite trying. The redundancy made her feel she wasn’t very good at her job, and the struggle to find a new work has made her doubt herself: “What’s the point” she asks. “I was never any good at anything at school, why should I think I could do a basic office job?”. Some days she struggles to get out of bed or get out of the house. She neither describes nor exhibits any signs of agitation.

What level of depression would you classify the patient?
Patient does not meet the technical criteria for depression
Depressive episode
Mild depression
Moderate depression
Severe depression
Question 1 Explanation: 

Under the ICD-10 criteria, the patient is exhibiting two typical symptoms (low mood and fatigue) and three other symptoms (change in appetite, lack of concentration - she can't focus on the TV - and sense of worthlessness) which would classify her a moderately depressed. The ICD-11 criteria for depression are less specific about the number of symptoms and more focussed on the severity of the symptoms. Under the ICD-11 criteria for mild depression, the patient "typically has some, but not considerable, difficulty in continuing with ordinary work, social, or domestic activities...". As our patient is struggling to leave the house, it is more likely she is suffering from moderate depression.

Normally, depressive symptoms would have to be almost daily for at least two weeks.

While this is a depressive episode, it meets the criteria for moderate depression. A depressive episode is one where the patient has some symptoms of low mood but not enough to classify as one of the other options.

See the summary at the end of the quiz for a discussion about classification of depression.

Question 2

Stem 1 - Question 2

You examine the patient for signs of thyroid deficiency. Which of the following is NOT a sign of hypothyroidism?
Cold hands
Delayed calcaneal reflect
Pitting oedema
Thinning hair
Question 2 Explanation: 
Both hypothyroidism and Graves' disease (a type of hyperthyroidism) can be associated with non-pitting oedema.
Question 3

Stem 1 - Question 3

Which of the following is NOT a tool that can be used to grade or screen for depression?
Question 3 Explanation: 
The AMT is used to score altered cognition. All the others are depression scoring tools. You will probably be more likely to use the PHQ-2 and PHQ-9 as these are free. The PHQ-2 is a very quick way to screen for depression.
Question 4

Stem 1 - Question 4

You explain to the patient that some high-intensity psychological interventions or medication would be appropriate. The patient would prefer to try medication. The doctor prescribes sertraline. What is the mechanism of action of sertraline?
Inhibits the breakdown of 5-HT in the synapse
Inhibits the breakdown of 5-HT in the neuron
Promotes uptake of 5-HT in the post-synaptic neuron
Blocks uptake of 5-HT in the pre-synaptic neuron
None of the above
Question 4 Explanation: 
Sertraline is a selective serotonin re-uptake inhibitor. Note, that the lady has had depression in the past so technically she has a recurrent depressive disorder, not that this would change the management significantly in this case.
Question 5

Stem 1 - Question 5

After eight weeks, during which time the dose of sertraline was increased, the drugs don't seem to be having an effect and the doctor proposes starting another medication and discusses options with the patient. She would prefer to be prescribed a different class of antidepressant. What would you recommend next?
Question 5 Explanation: 

SSRIs are the first line pharmaceutical treatment for depression. If there is no response to an SSRI you can try increasing the dose, an alternative SSRI or a more modern antidepressant.

The patient wishes to try a different class of medication. This rules out citalopram and fluoxetine. The BNF suggests mirtazapine. Venlafaxine would be considered in more resistant depression but it, TCAs and MAO inhibitors carry a greater risk of sider effects. Also see NICE guidelines. Note that the side effects of mirtazapine include weight gain and sleepiness, which also makes it a useful antidepressant to use in patients who are underweight or suffering from insomnia.

Pregabalin is a third-line treatment for generalised anxiety disorder (https://cks.nice.org.uk/topics/generalized-anxiety-disorder/management/management/).

Question 6

Stem 1 - Question 6

If you chose to prescribe amitriptyline, this drug might worsen her lethargy. What is the most likely reason for this?
Inhibition of the parasympathetic nervous system
Inhibition of histamine receptors
Inhibition of beta-adrenergic receptors
Inhibition of NA re-uptake
Inhibition of serotonin re-uptake
Question 6 Explanation: 
Tricyclic antidepressants act in five ways: inhibit re-uptake of NA and serotonin, and inhibit H1, alpha1 and muscarinic receptors. Histamine is responsible for alertness, which is why some antihistamines can cause drowsiness.
Question 7

Stem 2 - Question 1

Your next patient is a 78 year old gentleman who also comes to see you about low mood. His wife died last year and he has been struggling to get out and about in the last few months. He has several comorbidities, is a former smoker and drinks one glass of sherry a night. You assess he has mild depression. He recently saw a consultant at the hospital who changed his medication. He is currently taking aspirin, bisoprolol, dutasteride, simvastatin and a salbutamol inhaler.

Which of these medications could be responsible for his depressed mood?
Question 7 Explanation: 
Beta blockers and steroids are two medications that are 'classically' said to cause depressive symptoms, especially in older patients. That said, a 2021 meta-analysis published in Hypertension suggests there is no correlation between beta blockers and depression (see https://doi.org/10.1161/HYPERTENSIONAHA.120.16590. However, the same paper does confirm that beta blockers may increase the risk of insomnia and nightmares.
Question 8

Stem 2 - Question 2

You order some blood tests and these are the results:
Hb – reduced
WBC – normal
Platelets – normal
MCV – reduced
Haematocrit – slightly reduced
Reticulocytes – normal
CRP - normal
ESR - normal
TSH – normal
Bilirubin – low/normal
Albumin – normal
ALT/AST – normal
GGT – raised
Calcium – normal
Urea – normal
eGFR - 74
What is the possible cause of the patient's depression?
Anaemia of chronic disease
Chronic kidney disease
Iron deficiency anaemia
Liver failure
Question 8 Explanation: 

Other causes of depression can be remembered by the mnemonic: He'd be happier if he had A DIME. A - anaemia, D - vitamin D deficiency, I - infection, M - medication (see previous question) and E - endocrine.

In our patient's case, the reduced Hb and reduced MCV indicate iron-deficiency anaemia.

IMPORTANT NOTE: in this case, you would want to consider a two week wait referral to colonoscopy as the gentleman is over 60 and has iron-deficiency anaemia.

Anaemia can also be caused by chronic disease and kidney failure; however, the ESR is not raised, and although the eGFR is less than 90, an eGFR above 60 would still not be a major cause for concern here.

The GGT was raised; however, the other liver function tests were normal. Note the patient has a nightly sherry and alcohol can commonly cause the GGT to be raised.

Question 9

Stem 2 - Question 3

After addressing this possible cause you find that the gentleman still has mild depression. Which of these is not an appropriate first line treatment?
Computerised CBT
Individual self-guided CBT
Group CBT
Peer support programme for people who share the same chronic conditions as the gentleman
SSRI therapy
Question 9 Explanation: 
NICE recommends against the use of anti-depressants in first line treatment for mild depression. NICE guidelines recommend that for mild depression you first explain the diagnosis to the patient, then offer a low-intensity psychological or psychosocial therapy, chosen in discussion with the patient.
Question 10

Stem 2 - Question 4

Despite the patient’s efforts to engage with the psychosocial interventions he still is depressed and is started on an antidepressant. His other medication has not changed. What is the most appropriate treatment to start for this gentleman?
Fluoxetine + lansoprazole
Sertraline + lansoprazole
Question 10 Explanation: 
This is a trickier question as it tests your knowledge of managing depression in a patient with multiple comorbidities. First line treatment for depression is an SSRI which rules out the last two options. Fluoxetine is more likely to have drug interactions so is not recommended in this patient - citalopram or sertraline would be safer. If you look back at the stem, you will note the patient is on aspirin. A PPI should be prescribed alongside an SSRI in a patient on NSAIDs or aspirin. The NICE guidelines actually give some alternative options as well: a patient on aspirin would be recommended mirtazapine (although with side effects such as sedation, I'd be cautious about using that in an elderly gentleman) and patients on NSAIDs could also be offered moclobemide.
Once you are finished, click the button below. Any items you have not completed will be marked incorrect. Get Results
There are 10 questions to complete.
Take home messages
Depression can be defined by both ICD and DSM criteria. Here we use the ICD criteria.

The current criteria are found under the ICD-11 code 6A70:

  • almost daily depressed mood or diminished interest in activities lasting at least two weeks
  • accompanied by other symptoms including:
    • difficulty concentrating,
    • feelings of worthlessness or excessive or inappropriate guilt,
    • hopelessness,
    • recurrent thoughts of death or suicide,
    • changes in appetite or sleep,
    • psychomotor agitation or retardation, and
    • reduced energy or fatigue

A single depressive epidose can be categorised as mild, moderate or severe, which vary depending on the number and intensity of depressive symptoms and the impact on day-to-day life. Psychotic symptoms (see below) may also be present in moderate and severe depression.

Mild Moderate Severe
Symptoms Mild, some symptoms only Several symptoms present to a marked degree


large number present at a less intensity

Many or most symptoms to a marked degree


some symptoms manifest intensly

Day to day life (e.g. work, social, domestic, personal, education) Some impact but not considerable Considerable impact on some areas but still able to function in some Unable to function except to a very limited degree
Psychotic symptoms No Possibly Possibly

Psychotic symptoms can include:

  • negative hallucinations:
    • auditory: cries for help, screams
    • olfactory: bad smells
    • visual: demons and dead bodies
  • negative delusions:
    • nihilistic: believe that part of them is dying/dead
    • personal inadequacy: I can’t walk, I can’t eat/drink

Differentials for depression include:

  • recurrent depression – symptoms return after a period of several months
  • bipolar disorder – periods of depression interpersed with periods of mania
  • schizoaffective disorder – mixture of psychotic and depressive (or manic) symptoms, although the psychotic symptoms predominate
  • premenstrual dysphoric disorder – repeated cyclical depressive, somatic and cognitive symptoms that precede menses
  • postpartum depression – persistent depressive symptoms that are established within 6 weeks post-partum; NO psychotic symptoms – not to be confused with ‘baby blues’ that are transient

Depressive symptoms can also have iatrogenic and organic causes, recalled by the mnomonic A DIME:

  • Anaemia
  • Vitamin D deficiency
  • Infections
  • Medicatation (beta blockers and steroids in particular)
  • Endocrine dysfunction

Management of depression

Management of depression follows a biopsychosocial approach based on the severity. Any patient you assess to be suicidal should be immediately referred to the local crisis team. Patients in need of psychological therapies can often be referred via their GP, or a self-referral, to their local IAPT service (Improving Access to Psychological Therapies). NICE guidelines recommend:

  1. Explaning the diagnosis of depression to the patient and seeking their agreement with the diagnosis
  2. Conservative measures such as improving sleep hygiene, reducing alcohol use…
  3. Low-intensity psychological interventions including self-guided and group CBT (mild-to-moderate depression)
  4. High-intensity psychological interventions including individual CBT (i.e. with a dedicated therapist) and psychotherapy (moderate-to-severe depression, mild depression that hasn’t responded to low-intensity methods)
  5. Medication (moderate-to-severe depression) starting with SSRIs, and then trialling venlafaxine (SNRI), TCAs (e.g. amitriptyline) and MAO inhibitors (e.g. moclobamide). Remember: starting patients on anti-depressants can increase their risk of suicide
A note on ICD-10 criteria
If, like me, you find the ICD-11 criteria for depression a little wishy-washy, you may prefer to use the ICD-10 criteria instead (see pages 100-103). This breaks the symptoms of depression into ‘typical depressive symptoms’ and ‘other depressive symptoms’:

Typical symptoms Other symptoms
Depressed mood

Lack of interest/enjoyment

Lack of energy (marked tiredness after mild effort is common)

Reduced concentration and attention

Reduced self-esteem and self-confidence

Ideas of guilt and unworthiness (even in a mild type of episode)

Bleak and pessimistic views of the future

Ideas or acts of self-harm or suicide

Disturbed sleep

Diminished appetite.

Mild, moderate and severe depression can then broadly be classified by the combination of typical and other symptoms:

Mild Moderate Severe
 2 typical + 2 other 2 typical + 3/4 other

+/- psychotic symptoms

3 typical + at least 4 other (some very intense). May be particularly agiated or activity could be retarded (slowed)

+/- psychotic symptoms

Both ICD-10 and ICD-11 require symptoms to be present most days for at least two weeks. The main difference between the two is basically that ICD-11 does not consider a lack of energy a ‘typical’ symptom.

Spotted an error?

1 + 1 =