TY  - CHAP
M1  - Book, Section
TI  - Schizophrenia and Bipolar Disorder
A1  - Nestler, Eric J.
A1  - Kenny, Paul J.
A1  - Russo, Scott J.
A1  - Schaefer, Anne
Y1  - 2020
N1  - 
T2  - Nestler, Hyman & Malenka’s Molecular Neuropharmacology: A Foundation for Clinical Neuroscience, 4e
AB  - KEY  CONCEPTSSchizophrenia  is  characterized  by  psychotic  symptoms  such  as  hallucinations  and  delusions  (often  referred  to  as  “positive”  symptoms),  negative  or  deficit  symptoms  such  as  lack  of  motivation  and  social  withdrawal,  and  cognitive  impairments  affecting  attention,  working  memory,  declarative  memory,  language  fluency,  and  diverse  aspects  of  social  cognition.Bipolar  disorder  is  characterized  by  extreme  mood  swings  between  mania  (characterized  by  euphoria  or  irritability,  grandiosity,  increased  energy,  and  decreased  need  for  sleep)  and  depression  (characterized  by  sadness,  loss  of  interest,  decreased  energy,  disturbed  sleep  and  appetite,  ideas  of  worthlessness,  guilt,  and  suicidal  ideation).  Affected  individuals  may  return  to  normal  mood  states  (euthymia)  between  acute  episodes,  but  many  have  residual  symptoms.  Psychotic  symptoms  may  occur  in  either  manic  or  depressed  episodes,  most  often  congruent  with  mood.  Bipolar  patients  with  psychosis  may  have  cognitive  deficits  similar  to  those  seen  in  individuals  with  schizophrenia.A  milder  form  of  the  illness,  bipolar  II  disorder  is  also  recognized  in  which  hypomania  (mild  mania)  alternates  with  depression.  Such  patients  do  not  generally  suffer  psychotic  symptoms.Some  individuals  experience  a  mixture  of  symptoms  characteristic  of  schizophrenia  and  bipolar  disorder  and  are  currently  given  the  diagnosis  of  schizoaffective  disorder.The  heritability  of  schizophrenia  and  bipolar  disorder  is  estimated  to  be  very  high,  in  the  range  of  65%  to  80%.  In  contrast,  the  heritability  of  unipolar  depression  is  less,  approximately  35%,  with  greater  environmental  influence.The  genetic  basis  of  schizophrenia  and  of  bipolar  disorder  is  highly  complex.  For  both  diagnoses,  many  hundreds  of  common  genetic  variants  each  contribute  a  small  risk,  with  significant  overlap  of  the  genetic  risk  variants  observed  between  the  two  disorders.  For  schizophrenia,  rare  copy  number  variants  also  contribute  to  risk  in  a  subset  of  individuals.Schizophrenia  is  characterized  by  loss  of  gray  matter  in  frontal  and  temporal  regions  of  the  cerebral  cortex.  Unaffected  first–degree  relatives  may  have  milder  gray  matter  loss  with  similar  spatial  patterns.First–degree  relatives  of  individuals  with  schizophrenia  may  have  attenuated  symptoms  such  as  suspiciousness,  social  isolation,  eccentric  beliefs,  and  mild  cognitive  impairments  without  psychosis.  This  condition  is  currently  diagnosed  as  schizotypal  disorder.Antipsychotic  drugs  are  effective  for  the  positive  (psychotic)  symptoms  of  schizophrenia,  for  acute  manic  episodes,  and  when  combined  with  an  antidepressant  for  psychotic  depression.  They  are  also  efficacious  in  preventing  acute  relapses  in  schizophrenia  and,  often  in  combination  with  mood–stabilizing  drugs,  in  bipolar  disorder.  They  lack  efficacy  for  the  negative  and  cognitive  symptoms  of  schizophrenia.The  therapeutic  action  of  all  currently  approved  antipsychotic  drugs  depends  on  their  ability  to  antagonize  D2  dopamine  receptors.  This  mechanism  of  action  can  also  cause  significant  Parkinson–like  motor  side  effects.  Second  generation  antipsychotic  drugs  partly  mitigate  motor  side  effects  by  blocking  other  neurotransmitter  receptors  (most  significantly  5HT2A  receptors)  but  have  their  own  significant  side  effects,  in  particular,  weight  gain  and  elevation  of  serum  glucose  and  lipids.Lithium  is  effective  both  for  acute  mania  and  for  mood  stabilization  in  bipolar  disorder.  Certain  anticonvulsant  drugs,  such  as  valproate,  are  also  effective.  However,  which  of  these  drugs’  many  pharmacological  actions  is  responsible  for  their  therapeutic  efficacy  remains  unknown.  
SN  - 
PB  - McGraw-Hill
CY  - New York, NY
Y2  - 2024/04/23
UR  - neurology.mhmedical.com/content.aspx?aid=1174974930
ER  -