🩺 Low Mood

Low mood is a common presentation in UK primary care, representing a spectrum from transient distress to Major Depressive Disorder (MDD). In the UK, depression is classified by ICD-10 or DSM-5 criteria into mild, moderate, or severe based on the number and intensity of symptoms. It has a significant impact on quality of life and is a major cause of disability. Management is guided by the NICE stepped-care model, prioritising psychological therapies and lifestyle changes for mild cases and combining these with pharmacotherapy for moderate-to-severe presentations.

Patients typically present with at least two of the three core symptoms of depression for at least two weeks: low mood, anhedonia, and fatigue/decreased energy. Biological symptoms to screen for include early morning awakening (typically 2 hours before normal), weight loss, or change in appetite. Social history should explore occupational impact, alcohol consumption, and isolation. It is vital to quantify the severity by assessing worthlessness, excessive guilt, and suicidal ideation (intent, plans, and protective factors).

Full physical examination is necessary to exclude organic mimics, specifically checking for thyroid enlargement, skin changes, or signs of self-harm. On Mental State Examination (MSE), patients typically exhibit poor eye contact, psychomotor retardation, a low/flat affect, and monotone speech. Cognitive assessment may reveal 'pseudo-dementia' where the patient gives 'I don't know' answers. Assessment of risk to self and others is the most critical component of the examination.

Adjustment disorder, Bipolar affective disorder, Hypothyroidism, Dysthymia (persistent depressive disorder), Normal bereavement/grief reaction, Dementia.

Active suicidal ideation with a specific plan, intent, or access to means. Evidence of psychotic symptoms (auditory hallucinations or delusions). Significant self-neglect leading to dehydration or malnutrition. Risk to others. Sudden change in mood/behaviour in the elderly.

Baseline blood tests are required to exclude reversible causes: FBC (anaemia), TFTs (hypothyroidism), U&Es, LFTs (alcohol impact), Bone Profile (hypercalcaemia), and B12/Folate levels. Scoring tools like the PHQ-9 are used to categorise severity and monitor response to treatment. If cognitive impairment is prominent in an older person, a formal screen such as the GPCOG or 4AT may be appropriate. Neuroimaging is generally not indicated unless focal neurological signs are present.

Prior to diagnosing clinical depression, clinicians must rule out organic causes such as hypothyroidism, B12 deficiency, or hypercalcaemia. Always screen for bipolar disorder by asking about previous episodes of high mood or excessive energy to avoid precipitating mania with antidepressants. The 'two-question' screen (PHQ-2) is a valid initial tool in primary care. Initial management for mild depression focus on watchful waiting or low-intensity psychological interventions before pharmacological options.

Aligned with the MLA 'Mental Health' map. Focus on the NICE stepped-care model. Note the black triangle status of many antidepressants and the risk of SSRI-induced hyponatraemia, particularly in the elderly. Understand the 'washout' period required when switching between different classes of antidepressants, such as SSRIs and MAOIs.