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Effects of intrathecal thyrotropin-releasing hormone (protirelin) in refractory depressed patients
L B Marangell1, M S George, A M Callahan
1Biological Psychiatry Branch, National Institutes of Mental Health, Bethesda, Md, USA.
Background:
Therapeutic effects of the tripeptide protirelin (thyrotropin-releasing hormone) have been postulated in the affective disorders, but direct assessment in humans has been hindered by poor blood-brain barrier permeability.
Methods:
Eight medication-free inpatients with refractory depression received 500 micrograms of protirelin via a lumbar intrathecal injection and an identical sham lumbar puncture procedure, separated by 1 week, in a double-blind crossover design.
Results:
Five of eight patients responded to intrathecal protirelin, defined as a 50% or greater reduction in an abbreviated Hamilton Rating Scale for Depression score. Suicidality also was reduced significantly (P < .05). Responses were rapid and clinically robust, but short-lived.
Conclusion:
Administration of protirelin by an intrathecal route induced a rapid improvement in mood and suicidality in these refractory depressed patients, supporting the hypothesis that thyrotropin-releasing hormone could be a positive modulator of mood.