A Randomised, Double Blind Pilot Study of Minocycline and Placebo Added to Treatment-as-Usual (TAU) in First-Episode Psychosis

Background:

There is increasing clinical, neuropsychological and imaging evidence that schizophrenia involves a progressive process at the time of the first episode and later in life. However, it is not clear which systems are affected nor in which parts of the brain. In two Stanley first episode cohorts at Manchester (Stirling et al, 2004,) and in a group of elderly patients with schizophrenia (Gabrovska-Johnson et al 2004), evidence of deterioration in visuo-spatial functions has been found. This implies a right-hemisphere pathology. Other evidence suggests that the initiation of schizophrenia may involve left-sided pathology (Lawrie et al 2002) so it could be that right hemisphere pathology may follow left and give rise to the deficits of chronic schizophrenia (Gabrovska-Johnson et al 2004). If so, early treatment with a neuroprotective agent might prevent the accumulation of deficit symptoms and cognitive impairment.

Minocycline is a tetracycline antibiotic with proven long-term high dose safety in humans, is routinely used to treat acne and rheumatoid arthritis demonstrating that it acts as a non-steroidal anti-inflammatory, as well as an antimicrobial drug. Minocycline, unlike tetracycline, crosses the blood-brain barrier. This and related compounds show neuroprotective properties in rat models of ischemic brain damage, in glutamate neurotoxicity in cell cultures and in a rat model of Huntington's disease in which it slowed progression (Chen et al, 2000; Yrjanheikki et al, 1999). Minocycline delays disease onset and extends survival in amyotrophic lateral sclerotic mice (Shan Zhu et al 2002).

Minocycline has various properties including inhibition of capsases, inhibition of microglial activation, reduced cyclooxygenase-2 expression and reduced prostaglandin E (2) formation. Furthermore, it inhibits the formation of inducible nitric oxide - a mechanism of glial activation. All these mechanisms have been implicated in schizophrenia. All these mechanisms have been implicated in schizophrenia.

Because of its broad spectrum of action, we consider minocycline is an important candidate molecule for the prevention of deterioration in schizophrenia. Based on the evidence so far we propose a randomised double blind placebo controlled study of minocycline added to treatment-as-usual (TAU) in first-episode psychosis.