BMB 3 - Psychiatric Evaluation; Genetics of Psychiatry

Question 1

What are the broad questions to be answered in a psychiatric evaluation?

Answer 1

Is a mental illness present?

Does this need referral to psychiatry?

Question 2

What are the aims of a psychiatric evaluation?

Answer 2

Making a differential.

Dealing with immediate needs; making a treatment plan; fostering an alliance; identifying long-term issues.

Question 3

What sorts of aspects of the physical exam are important in a psychiatric evaluation?

Answer 3

Cleanliness,

signs of self-injury,

involuntary movements,

demeanor

Question 4

What is the basis of a mental status clinical interview?

Answer 4

Observational evidence

+

answers to specific questions (in the patient’s own words)

Question 5

What are the two main categories assessed in the psychiatric evaluation during discussion of the present illness?

Answer 5

Time course

Severity

Question 6

What important medical history is attained during a psychiatric evaluation?

Answer 6

Past episodes and/or diagnoses;

past suicide attempts or aggressive behavior;

history of substance abuse

Question 7

What important component’s of one’s social history are assessed during a psychiatric evaluation?

Answer 7

Childhood,

religiosity,

support system,

educational/occupational history,

parental divorce,

quality of relationships

Question 8

How do mental status exams work?

Answer 8

It is an observational exam – you observe while the patient performs the exam

Question 9

What sorts of factors are you observing while performing a mental status exam on a patient?

Answer 9

Appearance and behavior

Speech

Motor activity

Mood and affect

Thought content

Thought processes

Perceptual disturbance (hallucinations? Illusions?)

Insight (awareness of current issue)

Judgment (hypothetical decision making)

Cognition (orientation, awareness, memory, abstraction, etc.)

Question 10

Describe the genetics of most psychological conditions.

Answer 10

A complex mix of polygenic and environmental factors

Question 11

Do most psychological conditions follow a Mendelian form of inheritance?

Answer 11

No

Question 12

Which genetic factor explains the increase in incidence of psychological disorders as one ages.

Answer 12

Sporadic mutations

Question 13

Define heritability in terms of variation.

Answer 13

A statistical concept that describes how much of the variation in a given trait can be attributed to genetic variation (vs environmental)

Question 14

True/False.

An estimate of the heritability of a trait is specific to one individual.

Answer 14

False.

An estimate of the heritability of a trait is specific to one population.

Question 15

True/False.

The heritability of a condition can change when environmental circumstances change.

Answer 15

True.

Question 16

Define genetic inheritance.

Answer 16

The ability for a gene to be passed down through generations

Question 17

Define both variable expressivity and also incomplete penetrance in terms of individuals with some genotype linked to a genetic disorder.

Answer 17

Variable expressivity - individuals with the relevant genotype show differing levels of severity in their condition.

Incomplete penetrance - some individuals with the relevant genotype show no S/Sy of the disease at all.

Question 18

True/False.

Genetic heterogeneity refers to the production of single or similar genotypes through different environmental mechanisms.

Answer 18

False.

Genetic heterogeneity refers to the production of single or similar phenotypes through different genetic mechanisms.

Question 19

What term refers to the condition where multiple, different genes can each lead to a single, common phenotype?

Answer 19

Locus heterogeneity

Question 20

What term refers to the condition where multiple, different mutations of a single gene can each lead to a single, common phenotype?

Answer 20

Allelic heterogeneity

Question 21

Alzheimer’s disease is an example of a condition which shows __________ heterogeneity.

Answer 21

Alzheimer’s disease is an example of a condition which shows allelic heterogeneity (i.e. through APP or PSEN1 or PSEN2).

Question 22

What is assortive mating?

Answer 22

A form of sexual selection in which individuals with similar phenotypes mate with one another more frequently than would be expected under a random mating pattern.

Question 23

Some diseases, such as Alzheimer’s disease, that are complex diagnoses are due to individual genes.

These genes are known as genes of ________ ________.

Answer 23

Some diseases, such as Alzheimer’s disease, that are complex diagnoses are due to individual genes.

These genes are known as genes of large effect.

Question 24

Genes of large effect typically cause diseases which follow what sort of age-of-onset and inheritance pattern?

Answer 24

Early age

Mendelian inheritance

Question 25

For genes of large effect, the risk to first-degree relatives is ____%.

Answer 25

For genes of large effect, the risk to first-degree relatives is 4 %.

Question 26

An individual is diagnosed with Alzheimer’s disease.

What is the risk of his first-degree relatives being diagnosed in their lives?

Answer 26

4%

(For genes of large effect, the risk to first-degree relatives is 4%.)

Question 27

True/False.

50 - 75% of patients with risky genotypes for Alzheimer’s disease genes of large effect (e.g. heterozygous for ApoE4) don’t get AD.

Answer 27

True.

Question 28

Genes of ________ effect are useful in determining pathophysiology and treatment options; although, they do not typically predict likelihood of developing the disorder.

Answer 28

Genes of small effect are useful in determining pathophysiology and treatment options; although, they do not typically predict likelihood of developing the disorder.

Question 29

The DISC1 gene on chromosome 6 is strongly associated with ____________.

Answer 29

The DISC1 gene on chromosome 6 is strongly associated with schizophrenia (also overlaps with bipolar).

Question 30

True/False.

There is small association (1%) between the Ch22q11 deletions seen in DiGeorge / velocardiofacial syndromes and schizophrenia.

Answer 30

True.

Question 31

What is a polygenic risk score in terms of genetic disease?

Answer 31

A statistical analysis based on variation in multiple genetic loci and their association weights

Question 32

Give some examples of disorders for which polygenic risk scores are used in assessing one’s risk of developing the disorders.

Answer 32

Diabetes mellitus;

some forms of cancer

Question 33

Describe copy number variant testing.

Answer 33

Cgh microarrays are used to assess numbers of genetic variants of de novo duplications or deletions

Question 34

Give some examples of diseases for which copy number variant testing is useful in diagnosis.

Answer 34

Autism,

schizophrenia,

epilepsy

Question 35

What is a gene x environment study?

Answer 35

A study of the influence of life stress on chance of depression in those with long versus short alleles

Question 36

True/False.

Genetic testing is available and indicated for some diseases (e.g. schizophrenia).

Answer 36

True.

Question 37

What is the significance of the fact that genetic diseases are almost always partially dependent on some combination of both genetic and environmental factors?

Answer 37

One can often treat the disorders via a reduction in the environmental risk factors