Unipolar Depression

What is depression?

  • A mood (affective) disorder
  • Can be unipolar depression (first occurrence or recurrent) or bipolar (with reoccurrences of mania and depression)
  • The onset of individual episodes is often related to stressful events or situations
  • It usually runs a relapsing and remitting course


In depression, the aetiology is multifactorial. The usual way of presenting aetiological factors in psychiatry is by considering the “3 by 3 table” of Biological-Psychological-Social factors and Predisposing-Precipitating-Perpetuating. These can (and commonly do!) overlap.

An example of this would be:

Depression aetiology table
Depression aetiology table


There is a final factor to consider: the Protective factor (also from a Biological-Psychological- and Social aspect) that may lower an individual’s risk of developing a disorder:

Protective factors for depression
Protective factors for depression


Examples of aetiologies:


  • Genetics – e.g. family history of depression in the nuclear family increases the risk to almost 30-40% and up to 50% in monozygotic twins
  • Personality – e.g. dependent, anxious and avoidant traits
  • Physical illness (e.g. hypothyroidism or chronic illnesses)
  • Biochemical theories, monoamine deficiency – e.g. Serotonin imbalance causes depressive symptoms
  • Neuroendocrine – Hypothalamic-Pituitary-Adrenal (HPA) axis
  • Co-morbid substance misuse
  • Medication use (e.g. beta blockers, steroids)
  • History of other mental illnesses (e.g. anxiety)



  • Negative automated thoughts– cognitive theory of Beck (e.g. helplessness, hopelessness, worthlessness)
  • Life events
  • Environmental factors (e.g. support)
  • Lack of education



  • Social support
  • Poor economic status or support

Diagnostic Hierarchy

Just as with every case in psychiatry, there is a diagnostic hierarchy to consider (and if possible, rule out) before coming to a more definite diagnosis (Greg Lydall, 2009):

Diagnostic hierarchy
Diagnostic hierarchy


This ruling out system happens with investigative measures e.g. :

  • Thyroid function tests (TFTs) for hypothyroidism, an organic cause of low mood.
  • Urine drug screen for ongoing substance misuse
  • ?Medication use – beta blockers, steroids

Clinical Presentation

Depression is graded as mild, moderate or severe. A diagnosis of a depressive episode requires:

  • Symptoms present for at least 2 weeks (may be less if severe depression)
  • Symptoms are not attributable to other organic or substance causes, normal bereavement etc (remember your diagnostic hierarchy!)
  • Symptoms impair daily function and cause significant distress


These “symptoms” are known as the core/main and cognitive symptoms:

Core or Main symptoms (“MIE”)

  • Mood is low
  • Interest is lost (Anhedonia)
  • Energy is low (Anergia)


Cognitive Symptoms

  • Decreased concentration
  • Impaired memory
  • Pessimistic and self-blaming
  • Nihilistic

Where mild depression requires 2 core or main + at least 2 cognitive symptoms, moderate depression requires 2 core or main + at least 3 or 4 cognitive symptoms and severe depression requires all 3 core of main + at least 5 cognitive symptoms.

Taking this one step further, the ICD-10 criteria (1994) for unipolar depression is as follows:

  1. Mild depressive episode, with or without somatic symptoms
  2. Moderate depressive episode, with or without somatic symptoms
  3. Severe depressive episode, with or without psychotic symptoms – these may be mood congruent or incongruent psychotic symptoms

Where somatic (biological or physical) and psychotic symptoms commonly emerge as severity increases as summarised in the diagram below.


Cognitive symptoms depression

Somatic Symptoms

  • Marked loss of appetite or weight loss (some people experience the opposite)
  • Marked loss of libido
  • Sleep disturbances with early morning awakening (usually 2 hours or more before the usual time)
  • Diurnal variation of mood (worse in the mornings)
  • Psychomotor retardation or agitation – objective evidence, remarked on or reported by other people


The table below provides a clearer description of when with or without somatic symptoms is used, as per the ICD-10 classification.

ICD-10 classification of depression severity
ICD-10 classification of depression severity


Psychotic Symptoms

The two main psychotic symptoms to consider would be Hallucinations (commonly auditory, less commonly olfactory; visual; tactile) and Delusions (e.g. nihilistic or persecutory). These can be:

  • Mood-congruent (delusions/hallucinations that are consistent with typical depressive themes of e.g. guilt)
  • Mood-incongruent (delusions/hallucinations that are not consistent with typical depressive themes; including more first rank symptoms e.g. thought insertion).

Cotard Syndrome – e.g. patients think they are dead and their organs are rotting; they do not exist and cannot die because they are already dead.

Risk Assessment

  • Risk to self: self-harm, suicide or neglect (commonest in depression)
  • Risk to others: technically low-risk – unless psychotic features such as command hallucinations are present etc.


Should follow the bio-psycho-social model and is divided into short-term and long-term. “Treatment and care should take into account people’s individual needs and preferences. Good communication is essential, supported by evidence-based information, to allow people to reach informed decisions about their care” (NICE, 2009).

Thus, the management is dependent on symptoms the individual has – e.g. difficulty sleeping: practising good sleep hygiene and having a sleep diary.

Depression management
Depression management

Mild depression: Psychological and Social


  • First line: Low-intensity psychosocial interventions (NICE, 2009)
    • Computerised Cognitive Behavioural Therapy (CCBT)
    • Individualised CBT or Individual guided self-help based on CBT principles
    • Structured group physical activity programme
  • Psychoeducation of disease

Exceptional cases to consider starting on biological therapy (i.e. Antidepressants):

  • Past history of moderate or severe depression
  • Presence of mild depression that has been present for at least 2 years
  • Presence of mild depressive symptoms after other interventions


  • Risk assessment
  • Review them – response to low-intensity psychosocial intervention, compliance, symptoms etc.
  • Measurement scales to assess response to treatment and quality of life
  • Relapse prevention plan
  • Assess for social support and previous issues flagged up during consultations – e.g. poor sleep; is their sleep diary and hygiene helping?
  • If they were on antidepressant therapy – review compliance, use, side effects etc. and continue on same dose/increase/decrease as necessary

Moderate or Severe depression: Biological, Psychological and Social


  • First line: a combination of antidepressant therapy (biological treatment) and high-intensity psychosocial interventions (NICE, 2009) which will depend on if they have or do not have a chronic physical health problem (see below).
  • If they are presenting with a severe depressive episode with psychotic symptoms, then augmenting treatment with an antipsychotic (aripiprazole, risperidone, quetiapine or olanzapine)
  • Psychoeducation of disease

For people without a chronic physical health problem:

  • Individual CBT
  • Interpersonal Therapy
  • Behavioural Activation
  • Behavioural Couples Therapy


For people with a chronic physical health problem:

  • Group-based CBT
  • Individual CBT
  • Behavioural couples therapy



  • Risk assessment
  • Review their response to high-intensity psychosocial intervention compliance, symptoms, etc.
  • Review their response to antidepressant therapy, compliance, side effects etc. to continue on same dose/increase/decrease as necessary, to augment therapy with antipsychotics or mood stabilisers (e.g. lithium) if necessary
  • Measurement scales to assess response to treatment and quality of life
  • Relapse prevention plan
  • Assess for social support and previous issues flagged up during consultation – e.g. poor sleep; is their sleep diary and hygiene helping?

Depressive Stupor – Catatonia

It’s important to note that catatonia is NOT a disease – but instead a MODIFIER of a disease (in this case depression; an affective disorder). Catatonia can also be two ends of the spectrum: with stupor/ being entirely unresponsive to being excited with echolalia and stereotyping.

Treatment of choice is lorazepam and if life threatening then electroconvulsive therapy, ECT (M Justin Coffey, 2017). Treating the underlying cause is essential – as catatonia can cause people to NOT eat, NOT drink and NOT move – thus putting them at risk of:

  • Dehydration and malnutrition – Shock!
  • Increased Creatinine Kinase levels – Rhabdomyolysis
  • Deep Vein Thrombosis; Pulmonary Embolism – they aren’t moving!


Dr Nusrat Khan

Clinical Associate Professor and Consultant Psychiatrist

Newcastle University


1. Greg Lydall, M.D., Noreen Jakeman, Sheena Webb (2009) ‘Affective Disorders’, in Sarah Stringer, L.C., Susan Davison, Maurice Lipsedge (ed.) Psychiatry P.R.N. Oxford University Press.

2. ICD-10 (1994) ICD-10 Churchill Livingstone.

3. M Justin Coffey, M. (2017) Catatonia: Treatment and prognosis. Available at: https://www.uptodate.com/contents/catatonia-treatment-and-prognosis (Accessed: 23/01).

4. NICE (2009) Depression in adults: recognition and management.

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