Mood Disorders are extremes in normal mood. DSM-IV-TR distinguishes between depressive disorders and bipolar disorders, so we'll examine them separately.

Depressive Disorders

Major Depressive Episodes

(See Main Article: Major Depressive Disorder)
Major depressive disorder is characterised by MDE's - its main cluster of symptoms. It differs from normal unhappiness in severity (5/9 symptoms), long lastingness and level of impairment.

Dysthymic Disorder

Dysthymic Disorder is a milder, more chronic version of Major Depressive Disorder.


  • Persistently mild/moderate depressed mood that continues for 2+ years
  • Milder than major depression
  • Can persist unchanged over long periods (e.g. 20+ years)
  • Can combine with DDM to create Double Depression.

Course of Depressive Disorders

Klein (2010)


Causes of Depressive Disorders

Similarly to any of the other causal models of mental disorders, there are biological explanations and psychological explanations and biological+psychological explanations (e.g.).

Psychological Influences: Controllability

Learned Helplessness Theory of depresssion is the view that clinical depression is caused by people learning that they have no control over the negative events in their life.

LH and Cognitive Theory

Not all dogs exposed to uncontrollable shock developed LH. Perhaps because of the belief aspect - without irrational maladaptive thought processes, depression will not develop.

Cognitive Theories of Depression

Cognitive Therapy believes mental disorders are underpinned by irrational and maladaptive beliefs.


  • Biological
    • Pharmacological - SSRIs, tricyclics
    • Electro-Chemical Therapy
    • Home Remedies
  • Cognitive-Behavioural Therapy
    • Modifying Behaviours
    • Challenging Behaviours
  • Interpersonal Therapy
    • Focusses on identifying and resolving social/interpersonal triggers
      • Unresolved grief
      • Role disputes
      • Role transitions
      • Interpersonal deficits

Bipolar Disorders

Bipolar Disorder is a major depressive episode that oscillate with episodes of mania


  • Biological
    • Mood Stabilisers for Mania
    • Antipsychotics for Mania
    • Antidepressants for MDD
  • CBT
    • Identify and modify automatic thoughts
    • Control triggers
    • Manage behavioural symptoms

Genetics of Depression

There is a genetic contribution to depression for both MDD and BPD, although the genetics of mania are distinct from depression.

  • Twin has BPD: 40% chance of developing BPD
  • Twin has BPD: 25% chance of developing MDD
  • Twin has MDD: 40% chance of developing MDD
  • Twin has MDD: No extra chance of developing BPD (1-3%)