Study designs of evaluations included in the review
The inclusion criteria were not defined in terms of the study design. The included studies were before-and-after studies and one non-randomised controlled trial.
Specific interventions included in the review
Studies of psychoactive drugs or neuroleptics were eligible for inclusion. The included studies used classical neuroleptics (including 'moderate' doses and 5 to 15 mg/day), haloperidol (including 'moderate' doses and 15 mg/day), remoxipride, clozapine, fenfluramine, chlorpromazine (250 mg/kg and 351 mg/day), methylphenidate (0.5 mg/kg) and d-amphetamine (0.25 mg/kg). Where stated, the duration of treatment ranged from 15 minutes to 6 weeks.
Participants included in the review
Studies of patients with schizophrenia were eligible for inclusion. Studies that compared heterogeneous groups of diseases or patients were excluded. Where stated, the duration of illness ranged from first onset to 19.6 years and the mean age of the participants ranged from 15.5 to 42.6 years. The number of patients, their age, gender, educational level, form of schizophrenia and predominant symptomatology varied between the studies.
Outcomes assessed in the review
Studies that assessed language were eligible for inclusion. Studies that did not use quantified measures of language were excluded. The included studies assessed the following outcomes:
verbal flow type of sentences using free interview and picture description;
positive thought disorder (PTD) using Thought Disorder Index (TDI);
type of response using naming, picture description, free interview or linguistic measures;
poor responses using verbal comprehension;
frequency, amplitude and duration of acoustic measures at free interview;
clinical and linguistic measures at free interview;
verbal flow, verbal errors and repetitions using verbal fluency with a letter;
formal thought disorder using TDI; and
pauses, verbal flow, complexity of speech and PTD using free interview and linguistic measures.
How were decisions on the relevance of primary studies made?
The authors did not state how the papers were selected for the review, or how many reviewers performed the selection.