So brain is not
switched off at
night. State of
WINKLEMAN - Matched
pairs, 16 non medicated
insomniacs. 16 normal
sleepers. GABA levels.
Sufferers of more than 6
months had lower GABA
GENETIC PREDISPOSITION (Primary)
Sleep mechanism innate.
Inherited minor imbalance in
system leads to PI. Begins early
in life and runs in families
BEAULIEU & BONNEAU - 35% of primary
insomniacs had 1st degree relative with
WATSON ET AL - twin study. MZ
concordance 47%. DZ concordance 15%
Methodological issues with twin studies. Not controlled environment effects. MZ
treated more similarly like same person. DZ treated like siblings. Mz develop
same personalities e.g. neurotic and experience same traumas. Expect
concordance to be 100% for MZ
REDUCTIONIST. KALES - may develop
PI due to neurotic personality and
over tendency to internalise
Refers to time in CR that the
individual is most awake/alert. It is a
genetically inherited personality trait,
genes determine your CR.
Owls function best in evenings and not very active in mornings. MORE LIEKLY TO
SUFFER FROM INSOMNIA. Their CR peaks roughly 2 hours later than larks. More
vulnerable to sleep onset insomnia.
MORRIS ET AL - Sleep onset
insomnia have phase delay
pattern in rhythms of body
temp. Body temp peaks later
Methodological issues - correlational study.
Influenced by other EV e.g. work hours/noise levels.
MENTAL HEALTH PROBLEMS
KAMEROW - 10X more likely as a result of a MHP than a
PHP. Closely associated with depression. Share common
underlying mechanisms. Depressions shown to have
abnormality in the genes that govern CR's
OHAYON & ROTH - 14,195 ppts from
UK, Italy, Germany and Portugal,
interviewed over phone about psych
history and recent sleep patterns.
People with insomnia 6X more likely
to report MHP like depression or
GENDER BIAS - BETA, Insomnia
more common in females. More
likely to get stressed and develop
anxiety and have a neurotic