Insomnia

Insomnia

1. Biological Explanations

   • BRAIN CHEMISTRY (Primary)
     • Reduction in GABA, an inhibitory NT. So brain is not switched off at night. State of HYPER AROUSAL
     • WINKLEMAN - Matched pairs, 16 non medicated insomniacs. 16 normal sleepers. GABA levels. Sufferers of more than 6 months had lower GABA levels.
   • 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 insomnia
       • WATSON ET AL - twin study. MZ concordance 47%. DZ concordance 15% for PI.
     • 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 problems

2. Psychological Explanations

   • PERSONALITY (CHRONOTYPE) (Primary)
     • 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 than typical.
       • Methodological issues - correlational study. Influenced by other EV e.g. work hours/noise levels.
   • MENTAL HEALTH PROBLEMS (secondary insomnia)
     • 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 anxiety.
   • GENDER BIAS - BETA, Insomnia more common in females. More likely to get stressed and develop anxiety and have a neurotic personality.