Affective Disorders

Overview – Affective Disorders

Affective disorders, also known as mood disorders, are psychiatric conditions characterized by significant and often debilitating disturbances in emotional state. The two major forms include major depressive disorder and bipolar disorder, both of which are commonly encountered in clinical practice. These conditions impact mood, cognition, behaviour, and physiological functioning, and are associated with high morbidity and suicide risk. Early diagnosis and appropriate treatment are crucial for long-term outcomes.

Definition

Major Depression

• Persistent low mood, hopelessness, guilt, anhedonia
• Associated with insomnia, loss of appetite, poor concentration, and feelings of worthlessness

Bipolar Disorder

• Alternating periods of mania/hypomania and depression
• Mania: elevated mood, hyperactivity, insomnia, increased libido
• Depression: similar features to major depressive disorder

Aetiology

• Monoamine Hypothesis: Deficiency in noradrenaline (NA) and serotonin (5HT) in depression; surplus in mania
• Involves neurotransmitter imbalances, genetic vulnerability, and environmental stressors

Neurobiology & Pathophysiology

• Mood disorders linked to dysfunction in monoamine neurotransmitters:
  • ↓ NA & 5HT → Depression
  • ↑ NA & 5HT → Mania

Antidepressant Drug Classes

• Tricyclic Antidepressants (TCAs): Block reuptake of NA and 5HT
• Selective Serotonin Reuptake Inhibitors (SSRIs): Block 5HT reuptake
• Serotonin–Noradrenaline Reuptake Inhibitors (SNRIs): Block NA reuptake
• Monoamine Oxidase Inhibitors (MAOIs): Inhibit breakdown of NA and 5HT

Bipolar Drug Management

• Lithium: Mood stabiliser that ↑ serotonin and ↓ noradrenaline
• Valproate: Enhances GABA action → neurostabilisation
• Antipsychotics and anticonvulsants are often added depending on phase

Depression

Clinical Features

• Low mood, anhedonia
• Sleep and appetite disturbance
• Fatigue, psychomotor changes
• Poor concentration
• Recurrent thoughts of death or suicide

Risk Factors

• Female sex (2:1)
• Family history (depression, substance use, suicide)
• Adverse childhood events
• Recent life stressors
• Social isolation, poverty

Screening Tools

• K10 Scale: 10-item questionnaire assessing depressive/anxious symptoms
  • Scoring: 0–15 low, 16–30 moderate, 30–50 high risk

DSM-5 Diagnostic Criteria

Major Depressive Episode

• ≥5 symptoms over a 2-week period, including either depressed mood or anhedonia
• Must cause functional impairment
• Not due to substances or medical conditions

Major Depressive Disorder

• At least one major depressive episode
• Excludes manic/hypomanic episodes and psychotic disorders
• Specifiers: melancholic, atypical, anxious, seasonal, etc.
• Recurrent = ≥2 episodes separated by ≥2 months symptom-free

Persistent Depressive Disorder (Dysthymia)

• Depressed mood for ≥2 years (1 year in children)
• Plus ≥2 of: appetite change, insomnia/hypersomnia, low energy, poor self-esteem, poor concentration, hopelessness
• No remission ≥2 months
• No history of mania/hypomania

Postnatal Depression

• Non-psychotic depression within 4 weeks postpartum
• Lasts 2–6 months; affects ~12–15% of mothers
• Can lead to aversion to baby, suicidal or infanticidal ideation

Risk Factors

• Low socioeconomic status, young age, no partner, birth complications
• History of mental illness or abuse

Protective Factors

• Optimism, higher education, strong partner relationship

Screening

• K10 Score, Edinburgh Postnatal Depression Scale (EPDS)

Management

• CBT, SSRIs, ECT (severe cases)
• Monitor infant bonding and development

Bipolar Disorders

Bipolar I Disorder

• At least one manic episode
• May also experience depressive or mixed episodes
• Often requires hospitalisation

Bipolar II Disorder

• At least one hypomanic episode and one major depressive episode
• No full manic episodes

Mood Episode Types

• Manic: Lasts ≥1 week or requires hospitalisation
• Hypomanic: Lasts ≥4 days, less severe, no hospitalisation or psychosis
• Depressive: As per MDD criteria

DSM-5 Criteria – Manic Episode

• Abnormally elevated/irritable mood + increased energy
• ≥3 of: grandiosity, ↓ sleep, pressured speech, flight of ideas, distractibility, increased goal-directed activity, risky behaviour
• Causes impairment or hospitalisation

Treatment of Bipolar Disorder

Lifestyle

• Sleep hygiene, stress reduction, routine, contingency planning

Biological

• Lithium, valproate, carbamazepine, SGAs (e.g. olanzapine, aripiprazole)
• ECT for refractory or psychotic states

Psychological

• CBT, family therapy

Social

• Supportive care, vocational rehab, substance avoidance

Prognosis

• Bipolar disorder has a chronic relapsing course
• Suicide risk ~15% (higher in mixed states)
• High recurrence of mania (90% within 5 years)
• Many achieve good functioning between episodes

Summary – Affective Disorders

Affective disorders, including major depressive disorder and bipolar disorder, are high-burden conditions requiring early identification and multimodal treatment. Depression presents with sustained low mood and anhedonia, while bipolar disorder features alternating episodes of depression and mania or hypomania. Management includes pharmacotherapy, psychotherapy, and social interventions. For a broader context, see our Psychiatry & Mental Health Overview page.