L5- Antipsychotics (pathways)

Question 1

define psychosis

Answer 1

sustained mental state with impaired contact with reality

Question 2

list the components that define schizophrenia

Answer 2

• disturbed behavior, thinking, emotions, and perceptions
• Pos Sxs, Neg Sxs, Cognitive Sxs

Note- it is important to r/o medical causes of these Sxs before Dx can be made

Question 3

list the Positive Symptoms of Schizophrenia

Answer 3

(Pos = reflects excess of normal functions)

• hallucinations, delusions (w/o insight)
• perceptual disturbances (w/ insight)
• thought disorder (thinking beyond environment)
• incongruous mood (i.e. happy demeanor while telling sad story)
• inc motor function

Question 4

list the Negative Symptoms of Schizophrenia

Answer 4

(Neg = reflects diminution or loss of normal functions)

• blunted affected (lack of visual emotion)
• poverty of speech
• diminished motivation
• social withdrawal

Question 5

define cognitive symptoms of Schizophrenia

Answer 5

any deficit in memory and cognitive control of behavior

Question 6

positive symptoms of schizophrenia are related to (1) change in the (2) pathway

Answer 6

1- hyperactivity

2- mesolimbic pathway (Dopa)

Question 7

negative symptoms of schizophrenia are related to (1) change in the (2) pathway

Answer 7

1- hypoactivity

2- mesocortical pathway (Dopa)

Question 8

list the main dopaminergic pathways

Answer 8

• Mesolimbic: midbrain to limbic system (inc = pos Sxs)
• Mesocortical: midbrain to prefrontal cortex (dec = neg Sxs)
• Nigrostriatal: substantia nigra to basal ganglia (dec = EPR)
• Tuberoinfundibular: hypothalamus to ant. pituitary (dec = inc prolactin)

Question 9

Mesolimbic Pathway:

• (1) define pathway
• (2) define main function

Answer 9

1- midbrain to limbic system

2- controls emotional behaviors

Question 10

Mesolimbic Pathway:

• (1) involvement in psychosis
• (2) involvement in psychosis Tx

Answer 10

1- hyperactivity => positive symptoms of schizophrenia

2- D2 receptor blockade => dec pos Sxs

Question 11

Mesocortical Pathway:

• (1) define pathway
• (2) involvement in psychosis
• (3) involvement in psychosis Tx

Answer 11

1- midbrain to prefrontal cortex

2- hypoactivity => negative and cognitive symptoms of schizophrenia

3- D2 receptor blockade => worsening of neg. and cognitive Sxs

Question 12

Nigrostriatal Pathway:

• (1) define pathway
• (2) define main function
• (3) involvement in psychosis Tx

Answer 12

1- substantia nigra to basal ganglia

2- control of movements

3- D2 receptor blockade => movement disorder / EPR (extrapyramidal reactions)

Question 13

Tubulofundibular Pathway:

• (1) define pathway
• (2) define main function
• (3) involvement in psychosis Tx

Answer 13

1- hypothalamus to anterior pituitary

2- Dopa release inhibits prolactin secretion

3- dopamine receptor blockade –> inc prolactin levels –> galactorrhea (among other Sxs)

Question 14

Serotonin hypothesis for Psychosis:

• (1) are known hallucinogens and 5-HT agonists due to stimulation of (2) receptors and the modulation of (3) neurotransmitters
• therefore (4) is a key MOA of antipsychotics, particularly the (a-/typical) family

Answer 14

1- LSD, mescaline
2- 5-HT2(a)
3- dopa, NE, glutamate, GABA, ACh

4- 5-HT2(a) blockade (inverse agonists)
5- atypical antipsychotics