FINALS 3 - Schizophrenia - Genetics

Schizophrenic

There is a genetic component in schizophrenia shown by several types of data.

• The closer one’s relationship with a schizophrenic person, the more likely one is also to be __________

• first cousins

• Fraternal twins

• Identical twins

• 2%

• 10-20%

• 45-50%

Nearly 50%

children of two schizophrenic parents become schizophrenic

Blood relatives of schizophrenics

are 4-5 times as likely to be schizophrenic as are members of the families they were adopted into

Genetics

This means that ______ play a major role in the risk of developing schizophrenia

shared environment

while __________ seems to have less influence than biological factors when it comes to this particular disorder

• Dysbindin

• COMT

• CNR1

Most recently, the following possible gene linkages have been reported:

Dysbindin

a gene involved in the formation of synapses

Dysbindin

a gene that has been shown to be more variable in schizophrenics (although another group failed to confirm this)

• this again could lead to disruptions within the brains of schizophrenics

COMT

a gene that has been found by several research groups to be less active in some schizophrenics showing negative cognitive symptoms

COMT

the biochemical effect of this gene is to produce an enzyme that breaks dopamine in synapses

COMT

the occurrence of its weaker form coincides with decreased activity in the prefrontal cortex, and this in turn is associated with schizophrenic symptoms

• COMT

• dopamine

• prefrontal cortex

a weaker ____ gene → less ______ breakdown → disrupted brain activity in the _____ _____ → symptoms of schizophrenia

Cathecol-o-methyltransferase

COMT means

CNR1

a cannabinoid receptor

• a gene that codes for a cannabinoid receptor, is linked to schizophrenia with negative emotional and personality symptoms of schizophrenia

• this gene variant might make these symptoms more likely or more severe

Cannabinoid receptor 1

CNR1 means

Cannabis

increases the incidence of later schizophrenia by factor of 6

• In the short term it can induce (cause) psychotic states