major depressive disorder

sadness, helplessness, loneliness, anxiousness, numbness

• low self-esteem • pre-occupation with failure and self-blame

• difficulties with task initiation • impaired performance • difficulty with making decisions

loss of appetite • weight and sleep instability • fatigue • loss of libido • pre-occupation with personal health problems

• One in six (17%) met the criteria for a common mental disorder (CMD) • One in five women (19%) reported CMD symptoms, compared with one in eight men (12%). 10% of women reported severe symptoms compared to 6% of men • The trend has been upward for some time

> 12: Symptoms warrant clinical recognition >18: Symptoms severe, require intervention

i. 1.5-5 times greater occurrence among 1st degree relatives than in general population ii. Twin Studies: 48% MZ, 42% DZ concordance

iii. Higher vulnerability of women, different hormone cycle iv. Gene-carrier effect (female prone to depression, male prone to alcoholism)

serotonin system regulates norepinephrine and dopamine systems, and low levels of serotonin leads to mood deregulation • Serotonin system as a mood regulator • Regulates norepinephrine and dopamine activity • Depletion of serotonin results in deregulation of norepinephrine and larger mood fluctuation

(e.g., Nardil) • Inhibit the breakdown on monoamine neurotransmitters (norepinephrine and serotonin) in the synaptic cleft • Side effects: blood pressure, drowsiness/headache, fatigue, anxiety, mood shift, weight gain, sexual dysfunction, drug and food interactions (cheese, yoghurt, beer, etc.)

e.g, Tofranil [imipramine] • Block reuptake of monoamines into presynaptic cell • Side effects: dry mouth, sweating, constipation, blurry vision

• Specifically block serotonin reuptake * Side effects: anxiety/agitation, digestive problems, dizziness, dry mouth, sweating, low libido

• Early childhood adversity or abuse can lead to lasting difficulty in combating the effects of stress • In animals, lasting elevation in stress response has been shown following temporary early-life trauma • High levels of stress can damage the hippocampus • Impairs down regulation of stress response • Impairs memory

• Brain imaging studies are showing negative effects on the hippocampus of people with depression Cole et al. (2010)

In animals, lasting elevation in stress response has been shown following temporary early-life trauma

Serotonin levels can be reduced artificially by introducing an agent that depletes tryptophan (which is used in serotonin synthesis). When this is done with people who are in remission from depression, they can experience a relapse in their symptoms. This suggests that lower serotonin levels can be a causal agent in the onset of depression. However, the story is more complicated than this. When the experiment is done with people with no personal or family history of depression, no mood changes are found due to serotonin depletion. So, lower serotonin levels won’t bring about depressive symptoms in everyone.

red, green and blue routes

shows anxiety as the entry point. An easily available way to reduce anxiety is to numb oneself with alcohol. Large quantities of alcohol have a depressive effect on the nervous system. This impacts motivation and productivity, which end up increasing anxiety. Meanwhile the body develops tolerance for alcohol, so more alcohol is necessary to get the same numbing effect

shows perhaps the most insidious route into this vicious cycle. Frequent intake of large quantities of alcohol, perhaps as a social ritual, starts to depress the nervous system (where there was no dysfunction to begin with). Once depression kicks, the person starts to become anxious as well. This increases the need and attachment to heavy drinking as a means of dampening anxiety.

shows the cycle that can begin with, say, stress-induced depression. The state of depression brings with it personal non-coping and under-performance, which in turn elevates anxiety levels. At this point, if alcohol is chosen as self-medication, then it succeeds in deepening depression.

• Responding to improve things is ineffective • Formed through specific inescapably negative experiences • Become all-encompassing through stimulus generalization • Experimental results: • Escapability and helplessness • Explanatory style

Escapability & helplessness • Escapable shock => Escapable shock : Tries to escape • No shock => Escapable shock: Tries to escape • Inescapable shock => Escapable shock : Doesn’t escape

blame the self, external ones find causes outside the self.

imply that the reason for the outcome are persistent as opposed to transient (unstable).