Alterations in plasma dipeptidyl peptidase IV enzyme activity in depression and schizophrenia: effects of antidepressants and antipsychotic drugs

Acta Psychiatr Scand. 1996 Jan;93(1):1-8. doi: 10.1111/j.1600-0447.1996.tb10612.x.


Recently, our laboratory reported that the activity of dipeptidyl-peptidase IV (DPP IV) was significantly lower in the peripheral blood of major depressed patients than in normal controls. The present study examines plasma DPP IV activity in 43 major depressed and 13 schizophrenic subjects versus 21 normal controls and the effects of antidepressants and antipsychotic drugs on plasma DPP IV activity. DPP IV activity was significantly lower in major depressed subjects than in normal controls and schizophrenic subjects. There was a trend towards higher DPP IV activity in schizophrenic patients than in normal controls. There were no significant effects of antidepressants or neuroleptics on plasma DPP IV activity in depressed and schizophrenic patients, respectively. There were no significant relationships between plasma DPP IV activity and plasma cortisol or immune-inflammatory markers, such as serum interleukin-6 (IL-6) or soluble IL-2 receptor. A significant and positive correlation was found between plasma DPP IV and prolyl endopeptidase (PEP) enzyme activity in the study group as a whole and in schizophrenic subjects. The results support the hypothesis that lower and higher plasma DPP IV activities are trait markers of major depression and schizophrenia, respectively. It is concluded that alterations in the enzyme activity of peptidases, such as DPP IV and PEP, play a role in the pathophysiology of major depression and schizophrenia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antidepressive Agents / adverse effects
  • Antidepressive Agents / therapeutic use*
  • Antipsychotic Agents / adverse effects
  • Antipsychotic Agents / therapeutic use*
  • Bipolar Disorder / drug therapy*
  • Bipolar Disorder / enzymology
  • Bipolar Disorder / psychology
  • Depressive Disorder / drug therapy*
  • Depressive Disorder / enzymology
  • Depressive Disorder / psychology
  • Dipeptidyl Peptidase 4 / blood*
  • Dose-Response Relationship, Drug
  • Female
  • Fluoxetine / adverse effects
  • Fluoxetine / therapeutic use
  • Haloperidol / adverse effects
  • Haloperidol / therapeutic use
  • Humans
  • Hydrocortisone / blood
  • Imipramine / adverse effects
  • Imipramine / therapeutic use
  • Male
  • Middle Aged
  • Nortriptyline / adverse effects
  • Nortriptyline / therapeutic use
  • Perphenazine / therapeutic use
  • Psychiatric Status Rating Scales
  • Schizophrenia / drug therapy*
  • Schizophrenia / enzymology
  • Schizophrenic Psychology*


  • Antidepressive Agents
  • Antipsychotic Agents
  • Fluoxetine
  • Nortriptyline
  • Dipeptidyl Peptidase 4
  • Perphenazine
  • Haloperidol
  • Imipramine
  • Hydrocortisone