Psychiatric Genetic Counseling Flashcards
What is mental illness?
a condition that impacts a person’s thinking, feeling, or mood and may affect his or her ability to relate to others and function on a daily basis
many types
How is mental illness diagnosed?
via psychiatrist or psychologist
based on behavioral findings
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5)
What is the prevalence of mental illness?
1 in 5 New Yorkers experience a mental health disorder in a given year
What is the impact of mental illness on patients/
DALY (disability adjusted life years) = YLD (years lived with disease) + years lost due to disease (measurement of impact of disease)
cost
treatment
loss of life (leading cause of death in the US in 2015)
What is the historical etiology of mental illness?
until late 90’s: Parenting (‘Schizophrenigenic mother’)
debated nature vs nurture
current consensus is both nature and nurture have a role
most commonly explained as an ‘imbalance of chemicals in the brain’
What evidence is there that mental illness is genetic?
- family studies (greatest risk factor for an individual developing mental illness is a first degree affected relative)
- twin studies (suggests a significant genetic contribution that cannot be due to shared environment only)
- adoption studies (rate of mental illness in adopted children as compared to adoptive and biological families attempt to elucidate environmental versus genes BUT adoption is naturalistic setting and not easily manipulated groups; rate of mental illness in children adopted away from affected mother versus unaffected mother and children raised by unaffected parents)
What is the heritability thought to be for Schizophrenia?
70-86% (~80%)
although they cluster in families, the diagnoses are not specific (i.e. increased rate of schizoaffective, schizotupal, paranoid personality disorder, major depression)
studies all indicate a genetic role; they do not tell us about the genetic factors themselves
some genes may be harmful, increasing risk while others may be protective, decreasing risk
What rare disorders have psychological symptoms?
22q11.2 deletion syndrome Huntington disease Prader Willi syndrome Wilson disease Acute Intermittent Porphyria Ornithine Transcarbamylase Deficiency (in females) Fabry (females) Late-onset Tay Sachs Niemann Pick Type C X-linked Adrenoleukodystrophy Metachromatic Leukodystrophy Mitochondrial disorders
What genetic studies have been done for mental illness?
linkage and association has been largely unsuccessful (heterogeneity and complexity)
CNVs (rare but contribute significant risk; 1-2% not specific for schizophrenia)
SNVs (disrupt gene function; hard to find; SETD1A implicated; ASD variants often overlap)
GWAS (common, small effect)
What environmental factors may contribute to mental illness?
stress (often reported as a ‘trigger’, difficult to quantify)
drug use
paternal age (father >55 years old gives rise to double [2%] risk of schizophrenia and bipolar disorder)
OB complications (during pregnancy and delivery 2-4 times higher risk of schizophrenia; prematurity increased risk of mood disorders)
season of birth (increased risk for schizophrenia if born in winter or spring; stronger effect in Northern Hemisphere)
head trauma
urban upbringing
immigration
maternal famine
infection
What can genetic counselors do in the setting of mental illness?
assess family history estimate risk explain complex scientific information provide psychosocial support facilitate decision making
What are the steps to psychiatric genetic counseling?
contracting (establish goals, build rapport)
take family history (3 generations, targeted to psychiatric but also can be broad; ask about environmental factors)
take medical history (including triggers and environmental factors)
may be extremely emotionally charged
may be added need to clarify and assess accuracy of information
What protective factors make it less likely for us to experience an episode of mental illness?
stress reduction
adequate sleep or rest
regular meals and a healthy balanced diet
exercise and physical activity
a good support system of people you trust
taking medications suggested by a doctor
Describe the Empiric Risk Estimates for mental illness.
determined by studies looking at families of affected individuals
often differ between study are are AVERAGES (give a range, not a number)
often don’t fit the exact situation (multiple affected; both sides of the family; uncertain diagnosis)
Lowest risk is the general population risk
Highest risk is about 50% (this is when multiple generations of multiple affected members is present or both parents are severely affected)
can be modified based on individuals
