STEP 1

Schizophrenia

Definitition

Associated w/ increased activity of what nerve type?

How are axons/dendrites affected?

What increases risk in teens?

Are Genetics or Environmental Factors more important in the etiology of schizophrenia?

Periods of psychosis and disturbed behavior with a decline in functioning lasting greater than 6 months

Assoc w/ increased dopaminergic activity

Decreased dendritic branching

Marajuana use = risk factor in for schizophrenia in teens

Genetic factors outweight environment

STEP 1

Schizophrenia

Name 5 symptoms; How many are required for diagnosis?  Which of these symptoms are positive symptoms?

1. Delusions

2. Hallucinations - often auditory

3. Disorganized speech (loose associations)

4. Disorganized or catatonic behavior

5. Negative symptoms - flat affect,

social withdrawal, 

lack of motivation

lack of speech or thought

STEP 1

Brief psychotic disorder

Definition/usual assoc

STEP 1

Schizophreniform disorder

STEP 1

Schizoaffective disorder

What is it?

What are its 2 subtypes?

At least 2 weeks of stable mood w/ psychotic symptoms, PLUS a major depressive, manic, or mixed (manic and depressive) episode

Subtypes:

Bipolar

Depressive

STEP 1

5 subtypes of Schizophrenia

1. Paranoid (delusions)

2. Disorganized (w/ regard to speach, behavior, and affect)

3. Catatonic (automatisms - a set of brief unconcious behaviors)

4. Undifferentiated (includes elements of all types)

5. Residual

STEP 1

Describe the lifetime prevalence of Schizophrenia

(race, gender, age)

1.5% -  equal prevalence males/females, blacks/whites

Presents earlier in men (late teens to early 20s

vs. women present late 20s to early 30s)

Patients are at an increased risk for suicide

1. Substance abuse

2. suicide

3. Diabetes

4. Cardiovascular Disease

5. Less fertility

6. early mortality (death 25 yrs younger than average)

Schizophrenia genetics

Relatives of patients have a __ to ___ - fold increased risk vs the general pop

Concordance rate in MZ vs DZ twins?

How is risk affected when a child is adopted away from an ill mother?

5 to 10 fold

DZ twins have 50% concordance, this is 4 times higher than for DZ (10-15%)

Child has the same risk regardless of whether or not she is raised by the ill mother (adoptive environment may alter the risk a bit)

At-Risk alleles for Schizophrenia

Mosts of these alleles are assoc w/ what part of the nervous system?

How good are these alleles as indicators of incidence?

Many of the genes implicated overlap w/ risk for what other psychiatric disorder?

Does paternal/maternal age factor into schizophrenia risk?

Most are synapse genes

All the associated genes we know account for about 6% of cases (and less than 10% of the ppl w/ these at-risk genes show any symptoms)

Genes overlap w/ risk for Bipolar Disorder

Advancing paternal age explains 25% of risk (sperm divide thru lifetime, increased defects w/ time)

Describe Gross Pathological Changes in the Brains of ppl w/ Schizophrenia (7) 

What changes are occuring in the neural tissue(3), and what is the theory of why this is happening?

1. Larger fluid spaces

2. Diffuse loss of gray matter

3. Reduced hippocampal volume

4. Smaller frontal lobe

5. Smaller temporal lobe

6. Reduced corpus callosum thickness

7. Loss of normal assymetry

(less brain tissue overall)

Changes:

Increased Neuron density

decreased synapse density

smaller neurons (less gray matter)

Theory of increased synaptic pruning

1. Dorsolateral prefrontal cortex: working memory serves as an index for negative symptoms

2. Superior temporal gyrus - activated during auditory hallucinations

3. Thalamus 

4. Dentate gyrus of the hippocampus - abnormalities of neurogenesis observed here

Increased dopamine leads to psychosis, because DA increased the salience of irrelevant stimuli

Also, antipsychotic potentcy is directly proportional to its level of DA D2 receptor binding

NMDA Glutamate role in Schizophrenia:

Name a Glu agonist and antagonist, and how they fit in

2 Results of excessive NMDA activity?

NMDA Glu decrease leads to psychosis

PCP (an NMDA antagonist) causes a schizophrenia-like syndrome

Glutamate agonists (like glycine) may be somewhat therapeutic

NMDA OVERactivity leads to:

Excessive excitatory stim of frontal cortex

***Negative symptoms of schizophrenia

Serotonin Role in Schizophrenia

Agonist/antagonist effects?

What do path studies/PET scans tell us?

LSD is psychotogenic

Serotonin blockage seen in some atypical drugs

Autopsy results of schizophrenics show reduced 5HT receptors in prefrontal cortex...

BUT PET studies of living patients dont confirm these findings

Its a syndrome:

Multifactorial

separate diseases involved

Its a constellation of things

1. Neuromotor abnormalities in infancy and childhood (delayed milestones, speech problems, clumsiness)

2. Behavioral findings in childhood (isolated play, then social anxiety in teens)

3. Premorbid Cognitive Defecits (Lower IQ, ADD)

4. Congenital Anomalies (minor physical/craniofacial abnormalities)

Prodrome of Schizophrenia (2 symptoms that may precede true psychosis)

What % of cases progress to schizophrenia

Around or after puberty:

1. Decrease in school/social function

2. mild hallucinations

1/3 of cases progress to schizophrenia