Lecture 73: Biology of Psychiatric Disease Flashcards
Psychiatric diagnoses are described as (one word)
Categorical
Two diagnostic tools for psychiatry
Clinical interview, biomarkers (limited: DNA, imaging, labs)
Limitations of psychiatric dx (4)
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
Recently, the DSM has begun to focus more on ____________ than distinct disorders
Continuum
Limitations of biological psychiatric tx (3)
Treat symptoms (rare to cure); limited by adverse effects/placebo; no new mechanisms in decades
Why did the NIMH reject DSM-5 and their new platform
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
What is the NIMH’s new criteria called? Focus is no longer on traditional diagnostic categories, but…
Research Domain Criteria; specific domains and biological correlates (amygdala activation in anxious patients, for example)
T/F: Psychiatric disorders are highly heritable
True! Often up to 50%
Describe our current understanding of psychiatric genetics (2 main points)
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
SNPs studied in psychiatric disorders associated with…
Variety of mental health disorders
Heritability of common SNP variants > or
Much lower (0.25 compared to 0.75); gene x environment interactions
Describe structural abnormalities in schizophrenia
Early and late gray matter deficits, particularly in DLPFC
Describe structural abnormalities in depression
Decreases in hippocampal volume in untreated depression
Functional neuroimaging used in social phobia to show…how about in MDD?
Hyperactive amygdala; tx response in MDD
Major limitations of neuroimaging approaches (4)
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
Describe NT research transitions…
Research focus moved from monoamines –> receptors –> 2nd messenger/other more downstream systems
Hippocampal dysfunction in patients with psychiatric illnesses leads to…
Altered hippocampal neurogenesis
BDNF levels are affected by? Finding in depressed patients? Tx effects?
Levels of BDNF are affected by stress; low levels of BDNF found in hippocampus/PFC/serum of depressed pts; antidepressant treatment may normalize BDNF
Describe potential mechanisms of immune-inflammatory dysfunction in psychiatry (4)
Direct effects of pro-inflammatory cytokines on monoamine levels; dysregulation of HPA axis; pathologic microglial activation; impaired neuroplasticity
What’s a major challenge of animal models of psychiatric illnesses?
Hard to capture certain symptoms
