CHAPTER 16: SCHIZOPHRENIA AND THE AFFECTIVE DISORDERS
Schizophrenia – a serious mental disorder characterized by disordered thoughts, delusions, hallucinations, and
often bizarre behaviours.
Afflicts approximately 1% of the world’s population but its monetary cost to society is
enormous, (exceeds costs of cancer in the United States)
Three categories of symptoms; positive, negative and cognitive.
Positive symptoms – symptoms of schizophrenia evident by their presence: delusions,
hallucinations, or thought disorders.
Includes thought disorders – disorganized, irrational thinking. Probably most important symptom
Also includes delusions – beliefs that are clearly in contradiction to reality.
are false beliefs that others are plotting and conspiring against
are false beliefs in one’s power and importance.
In delusions of
, the person believes that he or she is being controlled by others.
Lastly, includes hallucinations – perceptions of nonexistent objects or events.
Negative symptoms – symptoms of schizophrenia characterized by the absence of behaviours that
are normally present: social withdrawal, lack of affect, and reduced motivation.
Anhedonia – inability to experience pleasure
Cognitive symptoms – symptoms of schizophrenia characterized by deficits in sustained attention,
psychomotor speed, learning and memory, abstract thinking, and problem solving.
Psychomotor speed – the ability to rapidly and fluently perform movements of the fingers, hand
Symptoms of schizophrenia typically appear gradually, over a period of three to five years.
Usually negative appear first, followed closely by cognitive, and years later, positive.
Either several genes are involved in schizophrenia or the “schizophrenia gene” imparts a
to develop the disorder, and it is later triggered by other factors.
Studies have found that children of older fathers are more likely to develop schizophrenia
Sperm cells divide every sixteen days and by the time a man is much older, they have divided so
many times that a replication error is more likely in the DNA.
No single gene has been located that can be called a “schizophrenic gene”