Abstract
The main objectives of this thesis were to establish the prevalence of psychotropic drug use as well as possible determinants associated with its use in multiple clinical settings: psychiatric admission wards, an intensive care unit and two settings for the intellectually disabled.
In this thesis, we evaluated the question which
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class of antipsychotics is prescribed preferentially in newly admitted patients on psychiatric admission wards and the determinants affecting this decision. We found that the most frequently prescribed oral antipsychotic drugs were classical agents. Initial choice for short-acting parenteral classical antipsychotics was significantly associated with follow-up prescriptions of oral classical antipsychotics. We predict that upcoming introductions of short-acting parenteral formulations of atypical agents are likely to have a large impact on the subsequent oral antipsychotic treatment. In another study on psychiatric admission wards, we looked at the temporal relationship between the use of antipsychotics and seclusion. Antipsychotic treatment in patients with psychotic disorders was significantly associated with a delay of seclusion and, although not statistically significant, with a lower risk of seclusion. Furthermore, in a substantial proportion of the patients, antipsychotic therapy was only initiated during or directly following seclusion with a relative risk of 2.0 (95% confidence interval: 1.2-3.4). Our findings suggest that, in patients with psychotic disorders, not using antipsychotics is associated with aggression or violence for which seclusion is needed. Pharmacological treatment seems inevitable for a substantial proportion of secluded psychotic patients.
Furthermore, we studied determinants of psychotropic drug use in a general intensive care unit (ICU). The prevalence of psychotropic drug use was 42.3%. Benzodiazepines were used in 35.8% of the patients, frequently at a high dosage. Antipsychotics were prescribed in 17.5% of all patients, typically in low dosages. The association of severe disease, a long ICU stay and an admission for non-surgical reasons with psychotropic drug use may be an indication that severely ill patients are likely to suffer from a delirium. In this study, patients who used psychotropic drugs (cases) acted as their own controls because days of drug exposure were compared to those of non-exposure and no corrections were made with the fact that observations were correlated. We compared this design with a logistical binomial model to adjust for correlated measures, or cluster effects through repeated measures and found that, although adjustment did not result in major changes in the odds ratios found, adjustment has greater effect with more observations per cluster.
In a study in group homes for intellectually disabled residents, the point prevalence of psychotropic drug use in a problem behaviour group (PBG) was compared to a random group (RG) of residents and possible determinants of group membership were studied. Psychotropics were used by 52.6% of the problem behaviour group and by 22.8% of the random group. Young age, psychotic, anxiety and aggression symptoms were significantly associated with the PBG. Remarkably, a low prevalence of antidepressants, mood stabilisers, antipsychotics and anxiolytics in patients with the corresponding symptoms was found. This suggests that a considerable number of residents remain undertreated. In addition, we examined the prevalence and possible determinants of multiple psychotropic drug use in intellectually disabled patients with mild intellectual disabilities admitted to a specialised closed psychiatric ward for prolonged treatment and rehabilitation. Multiple drug use was found in half of the patients. Psychotropics were used in high dosages and there was a tendency to prescribe multiple drugs for patients with duration of stay longer than a year. Furthermore, psychotic disorder, aggressive, bizarre, attention seeking behaviour and involuntary measures were associated with multiple psychotropic drug use. It is likely that these findings, especially the association with aggressive and attention seeking behaviour, indicate difficulties in the management of patients with socially disruptive behaviour.
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