Diphenylhydantoin and phenobarbital in the relief of psychoneurotic symptoms - A controlled comparison

This study is a double-blind comparison of the clinical effects of diphenylhydantoin (DPH) and phenobarbital among 80 adult psychoneurotic, non-epileptic outpatients. Patients were assigned at random to eight weeks of treatment with DPH 300 mg or phenobarbital 90 mg daily. During this time, patients were followed in brief bi-weekly interviews by one of two treating psychiatrists. At each visit, the patient's clinical condition was evaluated by the patient's ratings of distress on a factored list of 65 common psychoneurotic symptoms, on a mood adjective checklist, on the Psychiatric Evaluation Profile and on a global scale of change, and by the doctor's ratings on several global scales of change. Each criterion was analyzed with respect to initial score, medication, doctor and the medication by doctor interaction. The one doctor's patients responded better than the other doctor's patients. The results suggested that DPH and phenobarbital in the doses employed had similar effects on psychoneurotic symptoms. More extensive analyses of one patient rating and one doctor rating were performed to look for characteristics of the patient or the treatment situation that might affect medication responses. No useful predictors of differential response to the two medications appeared. Patients with brief illnesses, no prior psychiatric care and no previous phenothiazines or antidepressants responded better than their counterparts to both medications. Some patients who terminated prematurely reported very marked improvement-even more than most patients who completed the prescribed course of treatment. This observation challenges the usual assumption that drop-outs represent treatment failures. The equivocal results with regard to medication effects point up the potential value of studies designed to produce dose-response information.