PSYC*3410: Biopsychology of Psychiatric Disorders
Dopamine Theory of Schizophrenia
breakthrough, came from research on Parkinson’s
o 1960 found striatums of Parkinson’s had depletion of dopamine.
So… if chlorpromazine and reserpine cause Parkinson’s like symptoms then…
Dopamine Theory of Schizophrenia – schizophrenia caused by too much dopamine, and
anitschizophrenic (neroleptics) drugs decrease dopamine levels.
Reserpine works by breaking down synaptic vesicles of dopamine and
Cocaine and amphetamines known to cause schizophrenic episodes in healthy ppl
by increasing dopamine
Carlsson & Lindqvist (1963)
chlorpromazine works by binding to dopamine receptors, receptor blocker.
Revised theory: Cause of schizophrenia is high activity in dopamine receptors.
Snyder et al. (1970s)
Effective antischizophrenic drugs have high affinity for dopamine receptors,
o Potent treatment with low affinity.
o Discovered D1 (phenothiazines) and D2 (butyrophenones) receptors
Haloperidol – D2
Revised theory: Caused by hyperactivity at D2 receptors.
Development of atypical neurleptics, effective but bind to D1, D4 & some
o Clozapine – first atypical, promising, but blood disorders in some
Takes long time to start working, blocking D2 causes some sort of slow long
MRIs show continually developing brain damage to schizophrenics, not caused by
too much dopamine activity.
o Smaller brain – loss of white and grey matter
o Abnormalities in neuron structure & circuitry
Neuroleptics only partially relieve symptoms, must be other factors
Current View: hyperactivity is one of the factors, but there are others unidentified.
Affective Disorders: Depression and Mania ppl suffering from depression experience anhedonia – unable to feel pleasure, for
no apparent reason
o impairs ability to accomplish everyday tasks
o experience sleep disturbances and thoughts of suicide
Called Clinical depression or Major depressive disorder if lasts more than 2 weeks
Case of P.S – the weeping widow – age 57 depressed, treated with antidepressants
Major Categories of Affective Disorders
a psychiatric disorder characterized by disturbances of mood or emotions, also
called mood disorders.
o Mania – talkative, energetic, impulsive, positive, over confident
Bipolar affective disorder – depressed patients with periods of mania
Unipolar affective disorder – depressed patients not experiencing mania
Two categories of Depression:
o Reactive Depression – resulting from a negative event
o Endogenous Depression – no apparent reason (weeping widow)
Most countries chances of depression are 10%, women twice as often diagnosed
o 5% suicide rate
Associated with heart disease
Associated with bone loss in adult women
Causal factors of Effective Disorders
Twin studies – concordance rate of 60% (identical) 15% (fraternal)
o Reared together or apart
o Concordance in unipolar vs. bipolar as well
Seasonal Affective Disorder (SAD) – depression occurs every winter
Has to do with lack of sunlight
o More cases in northern than southern states
o Light therapy often effective
Postpartum Depression – intense depression following childbirth
lasts 13 months
10% of deliveries
Discovery of Antidepressant Drugs
Four major classes of antidepressants:
o 1. Monoamine oxidase (MAO) inhibitors – increase the levels of
monoamines (norepinephrine & serotonin) by inhibiting activity of MAO,
which breaks down monoamines.
Side effects: Cheese effect – foods high in tyramine, can cause
raised blood pressure = stroke
Ex. Iproniazid o 2. Tricyclic Antidepressents – block reuptake of norepinephrine and
safer alternative to MAO inhibitors
o 3. Selective MAOReuptake Inhibitors – selective serotoninreuptake
inhibitors (SSRIs) block the reuptake at the synapse.
Inspired selective norepinephrinereuptake inhibitors (SNRIs)
• Just as effective
o 4. Mood Stabilizers – antidepressants cause bouts of mania in bipolar, but
mood stabilizers do not
Not sure how they work
Also treat epilepsy
Lithium found to reduce mania and treat depression
• Guinea pig experiments (Cade)
Effectiveness of Drugs:
o Studies show that antidepressant only slightly improve patients and
placebos were 82% as effective as the actual drug
o Conclusion: Lithium and carbamazepine most effective for mania and
lamotrigine most effective for depression
Both are antiepileptics
Brain Pathology and Affective Disorders
Abnormalities of brain structures shown in brain scans:
o Anterior Cingulate cortex
Abnormal connection between the two
Theories of Depression
Monoamine Theory of Depression – depression is associated with under activity at the