Week 3: Mood Disorders: Major Depressive Disorder

This set covers vocabulary and key concepts related to Major Depressive Disorder (MDD), including diagnostic criteria, biological and cognitive models, and treatment approaches.

Affective Disorders

A group of conditions primarily associated with ongoing, severe disruptions to a person’s emotional state.

Major Depressive Episode (MDE)

A discrete time period of at least $2$ weeks where depressive symptoms are experienced.

Recurrent MDD

A clinical classification where an individual experiences multiple distinct major depressive episodes separated by a minimum $2$-month break in symptoms.

The Kindling Effect (Post, 1992)

The theory that repeated exposure to stressors plus neurochemical changes results in more frequent episodes without a clear cause.

Anhedonia

Markedly diminished interest or pleasure in all, or almost all, activities most of the day, nearly every day.

Hypophagia

Decreased appetite and reduced food intake, which results in weight loss.

Hyperphagia

Increased appetite and food intake, which results in weight gain.

Initial Insomnia

A sleep disturbance characterized by difficulty falling asleep.

Terminal Insomnia

A sleep disturbance characterized by waking too early.

Middle Insomnia

A sleep disturbance characterized by repeated wakening during the night.

Hypersomnia

A daily excess of $10$ or more hours of sleep that is not restful and results in sleep inertia upon wakening.

Psychomotor Agitation

Observable restlessness including fidgeting, constant pacing, increased talkativeness, and racing thoughts.

Psychomotor Retardation

Observable slowing including poor eye contact, a continuous fixed gaze, slowed walking speed, and sounding 'flat' in volume and prosody.

Rumination (Nolen-Hoeksema, 1991)

The obsessive mental replaying of negative events to the detriment of other stimuli, which prevents concentration and allows other symptoms to increase.

Passive Suicidal Ideation

Thoughts about death and suicide without a specific intent to act.

SLAP Assessment

An evaluation tool for active suicidal ideation that measures Specificity of Plans, Lethality of Method, Availability of Resources, and Proximity of Help or Rescuers.

Melancholic Specifier

A subtype affecting approximately $67 \%$ of individuals, characterized by non-reactive mood, insomnia, weight loss, and an overactive HPA axis.

Atypical Specifier

A subtype affecting $15-50 \%$ of individuals, characterized by mood reactivity, hyperphagia, hypersomnia, leaden paralysis, and an underactive HPA axis.

Catatonia

An episode specifier involving a lack of movement, muscle rigidity, or strange fixed postures.

Persistent Depressive Disorder

A unified DSM-5 diagnosis combining chronic Major Depressive Disorder and dysthymia.

Beck's Cognitive Model (Beck, 1967)

A model proposing that depression is the product of systematic negative biases in thoughts and negative cognitive schemas regarding the self, world, and future.

Learned Helplessness

The learned belief that nothing can be done to change adversity, categorized as universal (external attributions) or personal (internal attributions).

The Monoamine Hypothesis (Schildkraut, 1965)

The hypothesis that low levels of serotonin, norepinephrine, and dopamine are related to depressive symptoms.

Interpersonal Theory (Coyne, 1976)

The theory that depressive symptoms and excessive reassurance seeking cause interpersonal difficulties which push social supports away and perpetuate symptoms.

Loss of Positive Reinforcement (Lewinsohn, 1974)

A behavioral model based on operant conditioning suggesting symptoms arise when positive reinforcement is removed and continue due to unintentional reinforcement.

MAOIs (Monoamine Oxidase Inhibitors)

A first-generation antidepressant that blocks the enzyme monoamine oxidase from breaking down $5HT$, $NE$, and $DA$.

SSRIs (Selective Serotonin Reuptake Inhibitors)

A second-generation antidepressant that blocks the reuptake of serotonin ($5HT$) to boost mood.

Somatisation

The expression of emotional distress through physical signs, such as fatigue or aches, which is common in many non-Western cultures.