Lecture 73: Biology of Psychiatric Disease

Question 1

Psychiatric diagnoses are described as (one word)

Answer 1

Categorical

Question 2

Two diagnostic tools for psychiatry

Answer 2

Clinical interview, biomarkers (limited: DNA, imaging, labs)

Question 3

Limitations of psychiatric dx (4)

Answer 3

No genetic or neurobiological evidence; many patients don’t fit and can receive multiple dx; phenotype likely includes multiple disease processes; distinction between disorders arbitrary

Question 4

Recently, the DSM has begun to focus more on ____________ than distinct disorders

Answer 4

Continuum

Question 5

Limitations of biological psychiatric tx (3)

Answer 5

Treat symptoms (rare to cure); limited by adverse effects/placebo; no new mechanisms in decades

Question 6

Why did the NIMH reject DSM-5 and their new platform

Answer 6

DSM does not reflect complexity of disorders nor does it include genetic or imaging findings; no longer funds research that relies exclusively on DSM criteria

Question 7

What is the NIMH’s new criteria called? Focus is no longer on traditional diagnostic categories, but…

Answer 7

Research Domain Criteria; specific domains and biological correlates (amygdala activation in anxious patients, for example)

Question 8

T/F: Psychiatric disorders are highly heritable

Answer 8

True! Often up to 50%

Question 9

Describe our current understanding of psychiatric genetics (2 main points)

Answer 9

Mutations in multiple genes, each with small impact on risk; genetic influences transcend traditional clinical dxs –> individual risk factors linked to a range of disorders

Question 10

SNPs studied in psychiatric disorders associated with…

Answer 10

Variety of mental health disorders

Question 11

Heritability of common SNP variants > or

Answer 11

Much lower (0.25 compared to 0.75); gene x environment interactions

Question 12

Describe structural abnormalities in schizophrenia

Answer 12

Early and late gray matter deficits, particularly in DLPFC

Question 13

Describe structural abnormalities in depression

Answer 13

Decreases in hippocampal volume in untreated depression

Question 14

Functional neuroimaging used in social phobia to show…how about in MDD?

Answer 14

Hyperactive amygdala; tx response in MDD

Question 15

Major limitations of neuroimaging approaches (4)

Answer 15

Small ‘n’; increased/decreased activity in one brain region –> hard to determine what is abnormal, circuits > single brain regions (new studies starting to explore circuits); inconsistent results

Question 16

Describe NT research transitions…

Answer 16

Research focus moved from monoamines –> receptors –> 2nd messenger/other more downstream systems

Question 17

Hippocampal dysfunction in patients with psychiatric illnesses leads to…

Answer 17

Altered hippocampal neurogenesis

Question 18

BDNF levels are affected by? Finding in depressed patients? Tx effects?

Answer 18

Levels of BDNF are affected by stress; low levels of BDNF found in hippocampus/PFC/serum of depressed pts; antidepressant treatment may normalize BDNF

Question 19

Describe potential mechanisms of immune-inflammatory dysfunction in psychiatry (4)

Answer 19

Direct effects of pro-inflammatory cytokines on monoamine levels; dysregulation of HPA axis; pathologic microglial activation; impaired neuroplasticity

Question 20

What’s a major challenge of animal models of psychiatric illnesses?

Answer 20

Hard to capture certain symptoms