Biological Theories
Structural Theories
Abnormalities in the structure of the brain cause mental disorders
People who suffer brain damage or lesions show problems in psychological functioning that are
specific to that area of the brain.
Cerebral cortex plays a role in higher cognitive thinking
Perception, language, consciousness, memory, thinking
Temporal lobe – memory, emotion, hearing, and language
Frontal lobe – decision-making, problem solving, and planning
Parietal lobe – reception and processing of sensory info from body
Occipital System – Vision
Limbic System
Amygdala: 85% of disorders have a cause resulting from a problem in this area
Deals with the recognition of emotion, and fear (fight or flight)
Lesions in this area can bring about emotionally charged behavior
Hippocampus
Long term memory formation
Certain emotional memories will activate certain impulses in the brain and you begin to associate
emotions with memories
Emotionally-charged memories will be remembered more readily
Hypothalamus
Regulating eating, drinking, and sexual behaviors Control center in terms of the body’s functional systems
Produces hormones in response to stress (physical or psychological)
Biochemical Theories
Imbalances in neurotransmitters or hormones or poor functioning of receptors for
neurotransmitters causes mental disorders
Neurotransmitters are ‘messengers’– they carry impulses from one neuron to another in the brain
or other parts of the nervous system
Increased or decreased levels of neurotransmitters can cause psychological disorders – generally
by way of too many neurotransmitters released into the synaptic gap
Amalfunction in receptors can also be a cause for disorder
Inefficient enzymes may not break down the neurotransmitter (or even break it down too much)
that could also cause an imbalance
4 Main Neurotransmitters
Serotonin
Too little serotonin causes anxiety and depression
Dopamine
Schizophrenia, paranoia, and even Parkinson’s
Deals with reinforcement and reward
Can be affected by alcohol
Deals with muscle control (ie Parkinsons)
Norepinephrine
Deals with excitation
Related toADHD and anxiety disorders
Cocaine and other stimulants cause an increase in this, hence the stimulating effect of these drugs
GABA Deals with inhibitory actions
Dampens effect of other neurons
All neurotransmitters can interact and the malfunction of one can cause a disruption in the
function of another
Genetic Theories
An accumulation of disordered genes leads to mental disorders
Addresses two main question
To what extent are behaviors or behavioral tendencies inherited?
What are the processes by which genes affect behavior?
Genetics only pass down a PREDISPOSITION of a disorder, not the disorder itself.
46 Chromosomes
23 from dad
23 from mom
One pair is the sex chromosomes
Alterations in the structure or number can result in disorders
Structural differences are most common
It isn’t the number of genes but the sequencing of genes that appears to be important
Treatment
Medication
Phenothiazines
The Ca
More
Less
