Major Depressive Disorder
Causes
Pathophysiology
Diagnosis
Subtypes
Complications
Treatment
Nonpharmacologic
Pharmacologic
Serotonin Syndrome
References
Major Depressive Disorder (MDD) or clinical depression is a serious mental disorder
that can interferes with daily life → the patient feel that life is not enjoyable. The
lifetime incidents for MDD occurs to 20% women and 12% men.
Major Depressive Disorder 1
, Source: Major Depressive Disorder (MDD): Pathogenesis and Clinical Findings | Calgary Guide
(ucalgary.ca)
Causes
The causes of MDD is still unknown, but probably a combination of:
Genetics → people with family members who suffer from depression are more
likely to get depression → the risk is increased by 3x (but depend on how close
they're with that family members)
Biology → the regulation of neurotransmitter plays super important role in the
development of symptoms of depression (involve mood, attention, appetite, etc.)
Environment → major event, death or loss, physical or sexual abuse
Psychology → a triad of negative thoughts, recurrent depressive thinking
Pathophysiology
Monoamines Deficiency Theory
The monoamines:
Major Depressive Disorder 2
, Serotonin → have impact on obsessions and compulsions → the major
player (some theories said that serotonin is capable to regulate the two
others, but these theories are evidence limited)
Norepinephrine → have impact on anxiety and attention
Dopamine → have impact on attention, motivation, and pleasure
The causes of decreased monoamines is not well known, the research is still on
going. A decrease in the amount of tryptophan can also cause depression
symptoms, since it's the substance that used to make serotonin.
Neurotrophic Theory
Associated with Brain Derived Neurotrophic Factor (BDNF) deficiency
BDNF is important in the regulation of plasticity, resilience, and neurogenesis.
It influences neuronal survival and growth through activation of receptor
tyrosine kinase B in neurons and glial cells
Significant atrophy of the hippocampus and certain areas of the prefrontal
cortex was observed in the brains of people with depression as well as
decreased levels of nerve growth factors (NGF) such as BDNF
BDNF is thought to have an influence on neuronal survival and growth effects
by activating tyrosine receptor B kinase in both neurons (presynaptic and
postsynaptic) and glial cells
Antidepressant therapy for 2-3 weeks can increase neurogenesis and
synaptic signaling in cortical areas such as the hippocampus
Diagnosis
The criteria from Diagnostic and Statistical Manual of Mental Disorders, 5th Edition:
DSM-5
5 of 9 symptoms most of the day (nearly everyday)
Depressed mood
Decreased interest or pleasure
Significant weight loss or gain
Inability to sleep or oversleeping
Psychomotor agitation or impairment
Fatigue
Major Depressive Disorder 3
Causes
Pathophysiology
Diagnosis
Subtypes
Complications
Treatment
Nonpharmacologic
Pharmacologic
Serotonin Syndrome
References
Major Depressive Disorder (MDD) or clinical depression is a serious mental disorder
that can interferes with daily life → the patient feel that life is not enjoyable. The
lifetime incidents for MDD occurs to 20% women and 12% men.
Major Depressive Disorder 1
, Source: Major Depressive Disorder (MDD): Pathogenesis and Clinical Findings | Calgary Guide
(ucalgary.ca)
Causes
The causes of MDD is still unknown, but probably a combination of:
Genetics → people with family members who suffer from depression are more
likely to get depression → the risk is increased by 3x (but depend on how close
they're with that family members)
Biology → the regulation of neurotransmitter plays super important role in the
development of symptoms of depression (involve mood, attention, appetite, etc.)
Environment → major event, death or loss, physical or sexual abuse
Psychology → a triad of negative thoughts, recurrent depressive thinking
Pathophysiology
Monoamines Deficiency Theory
The monoamines:
Major Depressive Disorder 2
, Serotonin → have impact on obsessions and compulsions → the major
player (some theories said that serotonin is capable to regulate the two
others, but these theories are evidence limited)
Norepinephrine → have impact on anxiety and attention
Dopamine → have impact on attention, motivation, and pleasure
The causes of decreased monoamines is not well known, the research is still on
going. A decrease in the amount of tryptophan can also cause depression
symptoms, since it's the substance that used to make serotonin.
Neurotrophic Theory
Associated with Brain Derived Neurotrophic Factor (BDNF) deficiency
BDNF is important in the regulation of plasticity, resilience, and neurogenesis.
It influences neuronal survival and growth through activation of receptor
tyrosine kinase B in neurons and glial cells
Significant atrophy of the hippocampus and certain areas of the prefrontal
cortex was observed in the brains of people with depression as well as
decreased levels of nerve growth factors (NGF) such as BDNF
BDNF is thought to have an influence on neuronal survival and growth effects
by activating tyrosine receptor B kinase in both neurons (presynaptic and
postsynaptic) and glial cells
Antidepressant therapy for 2-3 weeks can increase neurogenesis and
synaptic signaling in cortical areas such as the hippocampus
Diagnosis
The criteria from Diagnostic and Statistical Manual of Mental Disorders, 5th Edition:
DSM-5
5 of 9 symptoms most of the day (nearly everyday)
Depressed mood
Decreased interest or pleasure
Significant weight loss or gain
Inability to sleep or oversleeping
Psychomotor agitation or impairment
Fatigue
Major Depressive Disorder 3
