OCD

Question 1

What is the concordance rate for OCD?

Answer 1

33% for MZ twins and 7% for DZ twins

Question 2

What other disease is OCD linked to?

Answer 2

Tourette’s Syndrome, it’s thought to share the same genotype.
Not clear why in some cases Tourette’s manifest in childhood and OCD in adults.

Question 3

Tell me the link between Pediatric Autoimmune Neuropsychiatric Disorder Associated w/ Steptococcus (PANDAS) and OCD…

Answer 3

PANDAS is a disease caused by an autoimmune reaction that damages the basal ganglia (caudate in particular) and OCD and/or TICS can develop following the strep infection.

Question 4

What do fMRI images show of brain activity in ppl w/ OCD?

Answer 4

Increased activation of orbitofrontal lobe and caudate

Question 5

What has OCD surgical studies involving electrodes implanted in the caudate shown?

Answer 5

Increased activity in patients having obsessive thoughts during surgery and lower rate of activity in patients without obsessive thoughts.

Question 6

Improvement in OCD symptoms is associated with…

Answer 6

Decreased activity of caudate and orbitofrontal area; durgs and beh therapy both produce this effect.

Question 7

In severe cases of OCD, what does CINGULOTOMY do in psychosurgery?

Answer 7

Severs the cingulum, which connects the orbitofrontal and cingulate w/ limbic temporal lobe (hippocampus+amygdala)

Question 8

In severe cases of OCD, what does CAPSULOTOMY do in psychosurgery?

Answer 8

Severs section of internal capsule connections between caudate and medial prefrontal.

Question 9

When is psychosurgery for OCD performed and what’s the outcome?

Answer 9

Only in SEVERE cases when it can’t be treated any other way and 54% show definitely or probably improvement.

Question 10

In psychosurgery w/ OCD, what happens to personality?

Answer 10

Negative personality changes are “very unlikely” w/ precision of modern surgery techniques. However, executive functioning deficits reported for some patients (planning, apathy, social disinhibition).
*man shot himself with a 22

Question 11

How is deep brain stimulation used for OCD tx?

Answer 11

Electrode implanted in subthalamic nucleus & internal capsule associated w/ reduction in OCD symptoms in some treatment refractory patients

Question 12

Whats the order for Brain Dysfunction in OCD (theory)?

Answer 12

1) The CAUDATE (learning and exec func)+PUTAMEN (regulate movmt and influence learning) receive input from entire cortex.

2) output thru 2 pathways to the THALAMUS (sleep & alertness) and FRONTAL LOBE (including prefrontal).
* Direct is excitatory
* indirect is inhibitory

Question 13

What’s the theory for OCD in the output pathways (thalamus and frontal lobe pathways)?

Answer 13

The imbalance btwn these two pathways results in OVERACTIVATION of direct excitatory path.

Question 14

Basal ganglia mediates what?

remember that cuaduate & putamen are in the Basal, motor fx

Answer 14

Execution of well-learned actions that are automatic so they can be executed rapidly.

Question 15

Orbitofrontal area recognizes what?

Answer 15

Situations of personal significance and can activate the pathway and the behavior it controls (brain dysfunction OCD pathway)

Question 16

The inhibitory indirect path does what?

Answer 16

Suppresses the automatic responses so you can switch to a different more adaptive response when needed.

Question 17

What happens when DIRECT pathway is activated?

Answer 17

It is excitatory and can’t switch to a diff response. That’s why OCD may result from direct path overactivation, where it can’t be suppressed by indirect path inhibition.

Question 18

The 3 drugs most effective for OCD are all ….

Answer 18

SSRI’S

Question 19

Which part of the brain receives the INHIBITORY input from SERATONIN neurons?

Answer 19

Orbitofrontal and Basal Ganglia

Question 20

DCS- the NMDA agonist w/ CBT results in what?

Answer 20

GREATER decrease in OCD symptoms after rx ends.