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PSY240H1 Chapter Notes -Transcranial Magnetic Stimulation, Circadian Rhythm, Melatonin

Course Code
Martha Mc Kay

of 6
Chapters 9 and 10
3 main symptoms: 1- Emotional ( feel irritable, anhedonia, sad, irritable) 2-
Physiological (tired, lack of energy, appetite) 3- Cognitive ( feel unworthy, delusional,
hallucinate, suicidal)
Double depression- dysthymia is the baseline and sink into major depression, and
have a 50% chance of being co-morbid with another disorder like panic, eating or
substance abuse
Depression can be a single episode, recurrent ( 2 months happy) or chronic
6 subtypes of depression: melancholic( no reactions and always sad), atypical (most
common, some +ve reactions), psychotic ( delusions, hear voices), seasonal ( sad in
winter, happy summer must be like this for at least 2 years), postpartum (occurs within 4
weeks of giving birth and may last 2 weeks, but some may develop into severe
depression), catatonic (strange behavior, lack motor skills)
Reasons why older adults may not be diagnosed as much as young people with
depression: a) less willing to report b) Depression may occur because of a serious
medical illness, so it is more difficult to diagnose c) DIfficult to distinguish b/w
depression and cognitive impairment which usually occurs at that age
The low rates may be attributed to: 1) Depression is severe and may affect physical
health so they may die before reaching old age 2) Old people may have learned to
adapt to their depression and learned to cope, so they experience fewer episodes
men more depressed than women, but men have higher rate if older and unmarried
Even after a depressed person recovers they still remain at high risk for a relapse
Treatment helps reduce the length of time of an episode and risk of relapse is reduced
If depression is not treated it worsens
Depression is less common among children than among adults.
Depression may be most likely to leave psychological and social scars if it initially
occurs during childhood, rather than adulthood.
Research at McGill: Negative, self-critical thinking at an early age predicts depression
and adjustment problems into adulthood
Young boys and girls experience depressive symptoms at equal rates, but diagnoses
for girls surge ahead with the onset of puberty
-Genes predispose you
-Dysregulation of neurotransmitters
-Abnormalities in brain structure: hippocampus, amygdala, prefrontal cortex,
-Dysfunction in HPA
-Monoamine theory of depression serotonin, dopamine, norepinephrine receptors
are the targets of pharmacotherapy
- too much or too little, occur at reuptake, degradation, and receptors
- SSRIs helps depression
-research on serotonin transporter gene, but also do to other genes
Imaging studies revealed differences in:
Frontal cortex
Cingulate cortex
Limbic-paralimbic regions: amygdala, hippocampus, parahippocampal
cortex, insula
Anterior temporal regions, superior temporal cortex
Subcortical thalamus, basal ganglia
Structural Findings
Reduced volume in amygdala, hippocampus
Reduced volume within frontal regions
Increased volume with successful treatment
Hyperactivity in vmPFC(ventromedial)
Hypoactivity in dlPFC(dorsolateral)
Evidence from imaging and lesion studies
Decreased activity in vmPFC & increased activty in dlPFC in response to treatment
Treatment targets these two areas:
Autonomic and neuroendocrine responses to stress
Generation of negative emotions; coordinates physiological components of
negative emotion
Cognitive control, manipulation of info in working memory
Hypoactivty associated with cognitive symptoms of MDD
Subgenual Cingulate- imp place and interest in this area, especially for -ve moods
Pharmacotherapy SSRIs, SNRIs, Tricyclics, MAOIs- very dangerous, people cant
eat certain foods, and they are risky, and interact with a lot of other drugs, and have
side-effects, mood stabilizers, atypical antipsychotics, psychostimulants
ECT - very controversial, high relapse rate, and results in memory loss, frightening, if
done nowadays done only on the right side of the brain to avoid memory impairment
Light Therapy - used to treat seasonal disorder, by resetting circadian rhythms- which
are natural cycles of biological activity that occur every 24 hours, which are regulated
by internal clocks and their dys-regulation can also mean the dysregulation of the
production of hormones and neurotransmitters, it may also work by reducing melatonin
which increases levels of serotonin and norepinephrine, which reduce levels of
Brain Stimulation through VNS (vague nerve stimulation) - The vague nerve carries
messages from the head, neck, thorax, and abdomen and several areas of the brain
such as amygdala, hypothalamus--> which are involved in depression
-This is conducted through two electro-generators placed on the chest and stimulating
the VNS, through electrodes implanted in the subgenual cingulate
-These are given to patients whos bodies resist treatment and cant recover, but 60%
have shown responded +vely
Transcranial Magnetic Stimulation- Enhances neurotransmission of the left-prefrontal
cortex through frequencies that stimulate. This is done through very powerful magnets
which are repeatedly exposed to patients
-Little side-effects
-patients have improved on their visual-spatial cognitive tests
Behavioural Therapy
Increase positive reinforcers and decrease aversive events by teaching the
person new skills for managing interpersonal situations and the
Cognitive-behavioural Therapy
Challenge distorted thinking and help the person learn more adaptive ways
of thinking and new behavioural skills
Interpersonal Therapy
Focuses upon actual grief or loss, interpersonal role disputes, role
transitions, and interpersonal skills deficits
Psychodynamic Therapy