Schizophrenia

Question 1

Positive symptoms of schizophrenia?

Answer 1

Disorders of thought/disorganised behaviour
Hallucinations
Paranoia

Question 2

Negative symptoms of schizophrenia?

Answer 2

Blunted emotions/anhedonia
Social withdrawal
Apathy/loss of energy
Cognitive impairment

Question 3

Environmental causes of schizophrenia

Answer 3

Family stress
 Poor social interaction
 Poor maternal nutrition
 Infection/virus at an early age
 Early trauma
 Obstetric complication

Question 4

Action of amphetamines

Answer 4

They get into the neurones in the presynaptic terminal. They push out dopamine, so more is available for the synapse.

Question 5

How is dopamine made?

Answer 5

Phenylalanine -> tyrosine -> L-DOPA -> Dopamine

Question 6

What is dopamine made form?

Answer 6

Amino acids

Question 7

Where is dopamine released?

Answer 7

At the synapse

Question 8

Where does dopamine act when it is released into the synapse?

Answer 8

The post-synaptic receptors (D1-D5)

Question 9

Which post-synaptic receptor is the pharmacological target for schizophrenia?

Answer 9

D2 receptor

Question 10

How do D2 receptor antagonist work?

Answer 10

It binds to the D2 receptor so dopamine cannot

Question 11

What is the D2 receptor?

Answer 11

It acts as a negative feedback mechanism, regulating the release of dopamine from the pre-synaptic neurone.

Question 12

What dopamine pathways is the target for schizophrenia?

Answer 12

Mesolimbic and Mesocortical

Question 13

What happened if other dopamine pathways are acted on?

Answer 13

Causes side effects

Question 14

What is the mesocortical responsible for?

Answer 14

Cognition, memory, attention, emotional, behaviour, and learning

Question 15

What is the nigrostriatal responsible for?

Answer 15

Movement and sensory stimuli

Question 16

What is the mesolimbic responsible for?

Answer 16

Pleasure and reward, seeking behaviours. Addiction, emotion. And perception.

Question 17

What does hyperactivity in the mesolimbic pathway cause?

Answer 17

Creates positive psychotic symptoms. The pathway may also mediate aggression.

Question 18

What does blockade of the D2 receptors in the mesolimbic dopamine pathway cause?

Answer 18

This has the effect of reducing the hyperactivity in this pathway that is postulated to cause the positive symptoms of psychosis.

Question 19

What can also happen when some parts of the mesolimbic pathway are blocked?

Answer 19

Can also block reward mechanisms, leaving patients apathetic, anhedonic, lacking motivation, interest, and joy from social interactions.

Question 20

What can the D2 receptors in the mesolimbic dopamine system mediate?

Answer 20

Positive symptoms of psychosis and the normal reward system of the brain (pleasure centre).

Question 21

What would the ideal drug do for schizophrenia?

Answer 21

Decrease dopamine in the mesolimbic pathway
Increase dopamine in the mesocortical pathway.
AND leaving dopaminergic tone unchanged in both the nigrostriatal and tuberoinfundibular dopamine pathways to avoid side effects.

Question 22

What does and increase in dopamine in the mesocortical dopamine pathway cause?

Answer 22

Treatment for negative and cognitive symptoms

Question 23

What does and decrease in dopamine in the mesolimbic dopamine pathway cause?

Answer 23

Treatment for positive psychotic symptoms