(from the journal abstract) The objective of this study was (1) determine which antipsychotic side effects (SE) schizophrenic patients consider the most distressing during treatment with typical antipsychotics, (2) measure the impact of actual and past SE on patients' attitude toward antipsychotics and (3) assess the influence of both on adherence. The 213 schizophrenics, treated with conventional antipsychotics, were recruited in two psychiatric hospitals in Hamburg. Subjects were assessed about type and severity of present and past side effects and their attitude and adherence to antipsychotic treatment. The 82 (39%) patients presented present SE while 131 (61 %) did not. Sexual dysfunctions (P < 0.001), extrapyramidal (P < 0.05) and psychic side effects (P < 0.05) were rated as significantly subjectively more distressing than sedation or vegetative side effects. Patients presenting with present SE compared with patients without present SE had a significantly more negative general attitude toward antipsychotics (P < 0.05), were more doubtful about their efficacy (P < 0.01) and were less likely to encourage a relative to take such a medication in case of need (P < 0.001). A regression analysis indicated that nonadherence was mainly influenced by negative general and efficacy attitudes toward antipsychotics and the experience of past or present antipsychotic side effects. All antipsychotic side effects, present or past, can have a durable negative impact on patient's attitude toward antipsychotic treatment and adherence. Non-adherence is mainly determined, among other factors, by these negative attitudes, which are partly influenced by the experience of past or present antipsychotic-induced side effects. (PsycINFO Database Record (c) 2004 APA, all rights reserved)