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The authors examined the effect of combined thioridazine (THI) and desipramine (DMI) for an early antidepressant response in 14 patients with a DSM III diagnosis of major depressive disorder with melancholia. All 14 patients received a constant dose of 200 mg DMI/day for 21 days while 7 patients received 100 mg THI/day for only the first 7 days. A significantly greater improvement from baseline Hamilton Depression Scale (HDS) scores occurred during the first 7 days in patients receiving both drugs. Possible mechanisms for this early antidepressant action are discussed.

Plasma fluphenazine levels and plasma total neuroleptic activity (as quantitated by the neuroleptic receptor binding assay) were related to therapeutic response in 15 DSM-III schizophrenic patients who received a predetermined, fixed dose of fluphenazine for 14 days. Mean neuroleptic activity of the plasma was 84% greater than can be accounted for by the parent fluphenazine alone, and varied widely between patients. A sigmoidal relationship between total neuroleptic activity of plasma and response was found, with a continued plateau of response at higher total neuroleptic levels. Furthermore, the RBA data suggested (P less than 0.002) that two populations of drug-responsive schizophrenics exist which may be discriminated by the total D2 binding activity of plasma required for response.

The time course of antipsychotic response following the initiation of an antipsychotic drug and functional dopamine receptor sensitivity were explored in a cohort of recently admitted psychotic (mood-incongruent) patients. The distribution of the latencies of antipsychotic response suggested at least two populations. Rapid responders (RRs) had 60% reduction of baseline psychotic symptoms by a mean of 5.5 days of drug treatment. Delayed/nonresponders required 2-7 weeks for a similar reduction of psychotic symptoms. The sensitivity of postsynaptic dopamine receptors was explored using a neuroendocrine probe: growth hormone response to the dopamine agonist, apomorphine (AP). RRs had an exaggerated growth hormone response to AP in comparison to delayed/nonresponders (P less than 0.05). Exaggerated sensitivity of postsynaptic dopamine receptors and rapid antipsychotic response following dopamine receptor blockade in RRs suggest a true functional dopamine hypersensitivity disorder in the RR group. In contrast, lower postsynaptic receptor sensitivity (as reflected by lower growth hormone response to AP) and failure of early response following dopamine receptor blockade focus attention away from dopamine hyperactivity as a relevant etiologic mechanism in delayed/nonresponders. Response rates to neuroleptic drugs and neuroendocrine probes of receptor sensitivity may separate two or more etiologically distinct diseases with schizophrenic-like symptoms.

Plasma haloperidol levels were compared to clinical response during the first 14 days of drug treatment in 14 DSM III-diagnosed inpatient schizophrenic patients using an improved methodology, which utilized predetermined constant dosages and derived a therapeutic range of plasma haloperidol levels from a curvilinear regression analysis. An inverted U-shaped relationship was found which reflected a significant curvilinear correlation (r = 0.66, P less than 0.02) between plasma levels (as assayed by gas chromatography) and improvement on the Serial New Haven Schizophrenia Index. A therapeutic window was suggested by the present study, with optimum patient response associated with plasma haloperidol levels of 4.2-11.0 ng/ml for the first 2 weeks of treatment.