Part 5: Mental Health Disorders (MDD)

DSM-5 diagnostic criteria

At least 5 symptoms

Must have one of:

• Depressed mood (dysphoria)

• Or loss of interest/pleasure (anhedonia)

AND 4 of

• Weight/appetite changes

• Fatigue

• Feelings of worthlessness

• Suicidal ideation/intent

• Reduced concentration

etc.

Heritability? (1)

• 30-50%

Brain structure (1→3) + note

• Volume reduction of

  • Frontal

  • Parietal

  • Temporal

• which improved with treatment

*But these may not be specific to MDD

Brain function main factor? (1→2)

• ACC + amygdala tend to be:

  • Hyperactive to negative stimuli

  • Hypoactive to positive stimuli

Other brain function aspects?

MDD + attention?

• Biased attention: filter out positive + focus on negative stimuli

Role of PFC?

• Less able to control focus → often "dwell" on negative, self-referential thoughts → persistent “pointless” feeling

Causes?

• Genetic vulnerability

• Social stressors

Social stressors that might trigger MDD (1)

• Childhood adversity or trauma can alter brain growth + reinforce negative self-beliefs

Integrated model