The Role of Insulin-Like Growth Factor-1 in

Schizophrenia

By Karen Kiernan

Aim of Article

Schizophrenia - Impaired Glucose Tolerance - Insulin Resistance - Type 2 Diabetes Mellitus

Antipsychotics?

Aim of Article

Role of IGF-1 deficiency

- Insulin Resistance

- Pathogenesis of Schizophrenia

IGF-1

Protein Hormone

Similar structure to Insulin

Stimulates cell growth

Inhibits apoptosis

Experiment

Patients with Schizophrenia - no previous treatment with

psychotropic medication

Healthy Comparison Subjects

Low risk of Diabetes

Simplified Indian Diabetes Risk Score

Age [years]< 35 035 - 49 20≥ 50 30 Abdominal obesityWaist <80 cm [female] , <90 [male] 0Waist ≥ 80 – 89 cm [female], ≥ 90 – 99 cm [male] 10Waist ≥90 cm [female], ≥ 100 cm [male] 20 Physical activityExercise [regular] + strenuous work 0Exercise [regular] or strenuous work 20No exercise and sedentary work 30 Family historyNo family history 0Either parent 10Both parents 20 Minimum score 0 Maximum score 100

Method

12 hour overnight fast - Glucose - Insulin - IGF-1

Results

Schizophrenia Patients

- Glucose – Similar to healthy subjects- High Insulin- Low IGF-1- High Insulin Resistance

- Negative correlation between Insulin and IGF-1

Connection with Schizophrenia? Deficiency of IGF-1

- Increased incidence of DM among patients with Schizophrenia

- Pathogenesis of Schizophrenia itself?

IGF-1 deficiency

Low Birth Weight Leanness Decrease in stature

All indicate increase risk of Schizophrenia

Also - Negative Cancer correlation

Genetics

Chromosome 12p13-q13

- Linked with Schizophrenia

- Close to gene coding for IGF-1

Pathogenesis

IGF-1 Neuro-protective Anti-apoptotic effect

Crucial for optimal neurodevelopment

Specific Hypothesis

High concentrations of IGF-1 receptors in Hippocampus

Hippocampus dysfunction in Schizophrenia

- Auditory HallucinationsHigher deficiency of IGF-1 - More severe

Auditory Hallucinations

Conclusion

Strong evidence of link

More studies needed!

Thank you for your attention

Source

Insulin and Insulin like growth factor1 anormalities in antipsychotic naive schizophrenia

American Journal on Psychiatry, October 2007