• Decreased dopamine signaling (AA) [R].
  • Lower DRD2 (A) [R].
  • Low striatal DRD2 availability (GG) [R]
  • High extrastriatal DRD2  (GG)[R]

The Minor "A" allele is associated with:

  • Needing higher dose of methadone [R].
  • A longer time to reach the maximum methadone dose (P=0.025) [R].
  • Better response to treatment with methadone than patients with GG genotype (AA) (AG) [R]
  • Tend to be better NoGo learners (AA) [R]. NoGo is a game measuring the ability to hold off on the action of button pushing [R]. Higher dopamine in the basal ganglia helps people learn to repeat rewarding behaviors, while lower dopamine leads to better learning from bad experiences. In a game where X usually yields more points than Y, people with boosted dopamine levels learn to choose X. People with decreased dopamine levels learn to avoid Y [R]. In non-medicated test subjects, genetic variations that influence dopamine signaling in the basal ganglia also impact so-called Go (choose X) and NoGo learning (avoid Y) [R].
  • Combination of the A allele of the DRD2 gene and the Met allele of the COMT gene predicts more severe depression. Patients with this genotype do not have the same response to patients with GG to ECT and do not achieve remission as often as those with the GG genotype [R]  
  • The effects of nicotine to newly exposed individuals revealed a greater feeling of perception, anger, and reduced fatigue (AA) [R]  
  • Higher risk of schizophrenia (A) [R]  [R]

The Major "G" allele is associated with:

  • 1.42X higher risk of schizophrenia (G) (p<0.00005) [R]  .
  • 1.6X increased risk for Schizophrenia (GG) (p<0.00005) [R] .
  • PTSD (G) (p = 0.021) [R] .
  • Decreased general cognitive ability (p=0.003) (GG) [R]
  • Increased risk of developing a stutter (G) (n=chinese population) [R]
  • 3.3 times more likely to have a dependence to nicotine (GG along with a copy of the Taql A1-allele) This combination of accounts for 13% of the susceptibility to nicotine addiction in our population [R]  
  • Faster learning (GG) [R]  
  • Alcohol dependence  (GG) [R]
  • Better with better backward serial recall, which includes retrieval demands (GG) [R]
  • More efficient in inhibiting unwanted action tendencies (GG)  [R]

This SNP is associated with (unknown alleles):

  • Maternal infant-directed vocalizing  [R]
  • Binge eating disorders [R]
  • Cognitive flexibility in patients with HIV who abuse alcohol  [R]
  • Recurrent miscarriages (Odds ratio=2.37) [R]
  • Weight gain  [R]  



Parent Gene: DRD2

Importance: 4
Less common allele: A = 24%
More common allele: G = 76%
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