Insulin and insulin-like growth factor-1 abnormalities in antipsychotic-naive schizophrenia.
OBJECTIVE
The purpose of this study was to examine the evidence for the insulin-like growth factor-1 (IGF-1) deficiency hypothesis in the pathogenesis of schizophrenia.


METHODS
The authors examined the fasting plasma levels of glucose, insulin, IGF-1, and cortisol in antipsychotic-naive schizophrenia patients (N=44) relative to age- and sex-matched healthy comparison subjects (N=44). Patients and comparison subjects were also matched for anthropometric measures and physical activity.


RESULTS
Schizophrenia patients had a significantly higher mean plasma insulin level as well as a significantly higher mean insulin resistance score relative to healthy comparison subjects. The mean plasma IGF-1 level was significantly lower in patients. IGF-1 levels had a significant negative correlation with plasma insulin levels. The total positive symptoms score as well as the hallucinations subscore had a significant inverse relationship with IGF-1 levels.


CONCLUSIONS
Deficient IGF-1 might underlie insulin resistance in schizophrenia. The IGF-1 deficit in antipsychotic-naive schizophrenia patients and its significant correlation with psychopathology scores suggest that IGF-1 might be potentially involved in the pathogenesis of schizophrenia.
Venkatasubramanian
Ganesan
G
Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bangalore 560029, Karnataka, India. gvs@nimhans.kar.nic.in
Chittiprol
Seetharamaiah
S
Neelakantachar
Narendran
N
Naveen
Magadi N
MN
Thirthall
Jagadisha
J
Gangadhar
Bangalore N
BN
Shetty
K Taranath
KT
D000328:Adult; D000886:Anthropometry; D014150:Antipsychotic Agents / Q000008:administration & dosage; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006946:Hyperinsulinism / Q000097:blood; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000172:deficiency / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000502:physiology; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000097:blood* / Q000175:diagnosis / Q000503:physiopathology; D012565:Schizophrenic Psychology
D014150:Antipsychotic Agents; D007328:Insulin; D007334:Insulin-Like Growth Factor I; D006854:Hydrocortisone