Rebound psychosis

For example, withdrawal of haloperidol in one patient revealed little change in either mental status or involuntary movements 3 weeks after discontinuation ( 478). In contrast, there was a marked deterioration in mental status and involuntary movements in this same patient 1 week after clozapine withdrawal. This rebound psychosis was attributed to increased dopamine release, a mechanism suggested by earlier observations made after withdrawal studies in humans and animals. For example, a study of the effects of abrupt withdrawal in rats showed increased and decreased striatal basal dopamine release with discontinuation of clozapine and haloperidol, respectively ( 479). The exacerbation of dyskinesia after clozapine withdrawal suggests that human nigrostriatal dopamine receptors (putatively involved in the emergence of dyskinetic movements) may be altered pharmacologically by this drug. 

Withdrawal rebound psychosis" should not be attributed to an antipsychotic prescribed during or immediately after clozapine withdrawal. 

Margolese, H., Chouinard, G., Beauclair, F., Belanger, M. (2004). Therapeutic tolerance and rebound psychosis during quetiapine maintenance monotherapy in patients with schizophrenia and schizoaffective disorder. Journal of Clinical Psychopharmacology, 22, 347-352. 

Rebound psychosis or delirium or both have been reported after withdrawal of clozapine (207-212). Clozapine withdrawal has also been associated with nausea, vomiting, diarrhea, headache, restlessness, agitation, and sweating (213,214), which occur as the result of cholinergic rebound and which may respond to anticholinergic drugs (215), and with dystonias and dyskinesias. Delirium and the return of dyskinetic movements can occur within days after clozapine withdrawal. 

Rapid discontinuation may lead to rebound psychosis and worsening of symptoms... 

Rebound psychosis may occur unless dose is very slowly tapered, by 100 mg/week or less... 

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