Insight and treatment attitude in schizophrenia: comparison of patients on depot and atypical antipsychotics

AIMS AND METHOD

To establish if participants with schizophrenia receiving depot antipsychotics had less insight than similar participants receivingoral atypical antipsychotics. We assessed the difference betweenthese two groups.

RESULTS

Participants on oral antipsychotics had greater insight thanthose on depot antipsychotics (ITAQ, P=0.01). In the multipleregression analysis, only receiving depot antipsychotics contributedsignificantly to explaining variance in insight (adjusted R²=0.135,F=8.99, P=0.004).

CLINICAL IMPLICATIONS

Depot antipsychotics seem to be prescribed to a subgroup ofpeople with schizophrenia who are likely to be less adherentbecause of lower levels of insight. These individuals are onsignificantly higher doses of antipsychotic medication. Cliniciansshould review their patients on depot antipsychotics at regularintervals.

Introduction

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Introduction

The concept of insight as it applies to psychiatry is a complexphenomenon. David (1990) proposed that insight consists ofthree overlapping dimensions: the recognition that one has amental illness, adherence with treatment and the ability tore-label unusual mental events (delusions and hallucinations)as pathological.

Lack of insight is a common symptom of the acute phase of schizophrenia, being described in 97% of acute cases in the World Health Organization International Pilot Study of Schizophrenia (World Health Organization, 1973).Lack of insight often responds to treatment, but it also persistsin a substantial proportion of people with schizophrenia (Cuesta et al, 2000), and tends to be associated with non-adherence (Mcevoy et al, 1989a;Sanz et al, 1998).

Non-adherence itself is associated with relapse, re-hospitalisation (Haywood et al, 1995; Fenton et al, 1997) and social breakdown,which result in substantial hardships and cost to patients,their families, and society as a whole. Depot antipsychotic medication is commonly prescribed in cases of poor adherence,particularly when covert non-adherence is suspected (Valenstein et al, 2001).Administration of a depot ensures either that a patient receivesadequate levels of medication or that their failure to receive medication is detected early (through refusal or failure toattend for depot administration). However, long-term treatmentwith depot antipsychotics has disadvantages. In particular,it is associated with an increased risk of extrapyramidal side-effects,tardive dyskinesia, weight gain and depression (Cookson, 1991).Depot medication involves painful injections, may require attendanceat depot or primary care clinics, could make patients feelless in control of their illness, and dose adjustments to reachoptimal dose can be time consuming.

Over the past decade, the introduction of atypical antipsychoticshas been accompanied by a reduction in the use of depot antipsychotics (Patel & David, 2005). A substantial number of patientshave switched from depot antipsychotics to oral atypicals withapparently beneficial results. For example, an observational study by Desai et al (1999) reported that switching fromdepot antipsychotics to risperidone tablets resulted in significant improvement of positive and negative symptoms, level of functioning, parkinsonism and dyskinesia.

However, a substantial number of patients remain on depot antipsychotic medication long term. This raises the question of whether thisis due to inertia, or reflects a rational clinical decisionbased on the benefits of reducing covert non-adherence in asubgroup of patients with poor insight. To answer this question,we tested the hypothesis that patients with schizophrenia ondepot medication would have lower levels of insight than similarpatients receiving oral antipsychotics. We also aimed to controlfor potential confounding variables such as symptom severity,side-effects and duration of illness.

Method

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Method

A cross-sectional assessment was undertaken of stable communitypatients with schizophrenia at two sites in the north westof England (Preston and Blackburn), both served by LancashireCare NHS Trust. The local research ethics committee approvedthe study.

The inclusion criteria were that participants were aged 18–65years, had an ICD–10 (World Health Organization, 1992)diagnosis of schizophrenia, had been stable in the communityfor the previous 6 months, and were currently prescribed either depot or oral antipsychotic medication. Patients who were prescribedclozapine were excluded, as they were considered to representa subgroup that would be pre-selected for treatment resistance,as were patients who were taking both oral and depot medication.Written informed consent was obtained from all participants.A pre-study power calculation specified that 26 participantsper group were required for an 80% power to show a statisticallysignificant difference between the two groups at the 5% significancelevel, using a two-sided t-test.

Basic demographic, clinical and social characteristics werecollected using a structured questionnaire. Insight and attitudeto treatment was assessed using the Insight and Treatment AttitudeQuestionnaire (ITAQ) (Mcevoy et al, 1989b). The ITAQ is asemi-structured interview of 11 items that measures awarenessof illness (first 5 items) and attitude to medication/hospitalisationand follow-up evaluation (6 items). Scores range from 0 (noinsight) to 22 (full insight).

The Brief Psychiatric Rating Scale (BPRS; Overall & Gorham, 1962) was used to assess psychopathology. The BPRS contains 16 itemsthat measure negative symptoms (2 items), positive symptoms(5 items) and general psychopathology (9 items).

Akathisia was assessed using the Barnes Akathisia rating scale(BARS; Barnes, 1989). This scale is observer rated and includesitems for the objective and subjective aspects of akathisiaas well as a global rating. The Extra Pyramidal Side EffectsScale (ESES; Mcevoy et al, 1991) was used to assess bradykinesia,rigidity and tremor. Tardive dyskinesia was assessed usingthe Abnormal Involuntary Movements Scale (AIMS; Guy & Ban, 1979).

The dosage of each antipsychotic was converted to its chlorpromazine equivalents (Lehman & Steinwachs, 1998; Woods, 2003).

The Statistical Package for Social Science (SPSS) for Windows,Version 10 was used for the analysis. Univariate tests wereused to assess differences between the depot antipsychoticgroup and the oral antipsychotic group. For all tests, thelevel of significance (P) was set at the conventional levelof 0.05 (two-sided).

Multiple regression was used to analyse the relative contributionof symptom severity (BPRS score), side-effects (BARS, ESESand AIMS scores), duration of illness and group membership(depot or oral) to insight (ITAQ scores).

Results

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Results

We recruited 52 participants, of which 26 were receiving depotmedication and 26 were on oral medication. The demographiccharacteristics of the participants are summarised in Table 1.The mean age of participants was 44.4 years (s.d.=11.9) in the depot group and 42.0 years (s.d.=13.7) in the oral group. Inboth groups the majority of the participants were male (depot80.7%; oral 73.1%) and single (depot 65.4%; oral 57.7%). Moreparticipants from the depot group were living alone (depot42.3%; oral 15.4%) and the majority of participants were unemployed(depot 95.2%; oral 92.3%). No differences reached statistical significance.

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Table 1. Characteristics of the depot and oral antipsychotic groups

In the oral antipsychotic group all the participants were onatypical antipsychotics. In the depot group 23 participantswere on typical depot medication and 3 were on risperidonelong-acting injection. The mean chlorpromazine equivalent doseof antipsychotic was much higher in the depot group than theoral antipsychotic group (1388.7, s.d.=1870.7 v. 391.0, s.d.=205.5;z=–3.16, P=0.002).

Illness variables for the two groups are summarised in Table 2.The mean age at onset of psychotic symptoms for the whole samplewas 26.1 years (s.d.=8.8) and the mean duration of illnesswas 17.2 years (s.d.=9.7). The mean duration of illness wassignificantly longer for the depot group than the oral group (20.2, s.d.=9.5 v. 14.1, s.d.=9.1; P=0.02, 95% CI 0.9 to 11.3).More patients from the depot group had a history of compulsory admission under the Mental Health Act (76.9% v. 53.9%, P=0.07)compared with the oral group.

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Table 2. Illness variables and side-effects scores between the depot (n=26) and oral (n=26) antipsychotic groups

The mean BPRS score of the total sample was 28.0 (s.d.=7.9).The depot group had a slightly better mean BPRS score thanthe oral group but this difference was not statistically significant(27.0, s.d.=7.4 v. 29.0, s.d.=8.5; P=0.36, 95% CI –6.5to 2.4).

Overall the level of insight was fairly high, with the totalsample having a mean ITAQ score of 17.6 (range 10–22,s.d.=3.5). However, the patients on oral medication had a statisticallysignificantly higher mean score than those on depot (16.3,s.d.=4.0 v. 19.0, s.d.=2.3; z=–2.4, P=0.01). A sub-scoreanalysis of the ITAQ showed that the oral medication groupscored significantly higher than the depot group on both awarenessof illness and attitude to treatment (Table 3).

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Table 3. ITAQ scores in the depot (n=26) and oral (n=26) antipsychotic group

Overall the sample had relatively low levels of side-effects (Table 2). There was no significant difference between thetwo groups other than for the tardive dyskinesia (AIMS score).

Total scores for BPRS, AIMS, ESES and BARS, duration of illnessand group were entered as independent variables in a stepwisemultiple regression analysis, with ITAQ score (as the dependentvariable). Only group (depot or oral) contributed significantlyto the regression model (adjusted R²=0.135, F=8.99, P=0.004).

Discussion

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Discussion

The participants in this study had relatively high levels ofinsight into their illness. The study sample consisted of stableout-patients. This finding is consistent with previous reportsof higher insight among out-patients with schizophrenia (Garavan et al, 1998;Williams & Collins, 2002).

The findings of the study confirmed our hypothesis that participants receiving depot antipsychotics would have significantly lessinsight than those receiving oral antipsychotics. This resultwas supported by our additional finding that participants ondepots were also more likely to have been admitted to hospitalunder the Mental Health Act, suggesting that they were lessadherent with medication than the group receiving oral antipsychotics.This suggests that psychiatrists were taking adherence and/or insight into account when deciding to start and maintain patientson depot medication.

It can be hypothesised that the majority of the participantson oral antipsychotics were started and maintained on oralantipsychotics because of their better insight and adherence.However, because of the cross-sectional nature of the studydesign, it is not possible to ascertain the insight of the participantswhen they were started on their medication.

The finding of poorer insight among participants taking depotmedication is open to an alternative explanation that the depotmedication was less effective than the oral medication at improvinginsight. However, against this explanation is the fact thatthe two groups had similar levels of symptomatology. This finding,together with the similar level of side-effects between thetwo groups, reflects the broader evidence base that depots areas effective and safe as oral antipsychotic medication forthe treatment of schizophrenia (Adams et al, 2001).

Insight was shown to be a clinical modulator of long- and short-term adherence with treatment and is a good indicator of prognosis (Buchanan, 1992). The clinical relevance of the findings fromthis study is that appropriate interventions should be offeredto patients on depot medication to improve their insight. Thiswill have a beneficial effect on adherence and long-term prognosis.

We found that the participants on depot antipsychotics wereon significantly higher doses of antipsychotic medication comparedwith those on atypical medication, to the ratio of 1:35. Theparticipants on depot medication were on a mean chlorpromazineequivalent dose of 1388.7 mg; well above the recommended rangeof 300–1000 mg chlorpromazine equivalent. Cliniciansshould review the patients on depot antipsychotics at regular intervals and review the dose of their depot medication.

It is possible that the findings of the study are only locallyapplicable to the sites in east Lancashire, as the study isrelatively small and restricted to patients from this area.None the less, as far as we are aware, this study providesthe best evidence so far that the decision to put patients ondepot rather than oral medication is being made on a rationalbasis. Future studies should address this question in largercohorts of patients, where changes in adherence are observedover time from the inception of the antipsychotic medication.

Acknowledgments

We thank Dr Saleem and Maureen Eka Harrison (Queens Park Hospital, Blackburn) for their help in recruiting participants. Thesefindings were presented as a poster at the Royal College ofPsychiatrists Annual General Meeting of the Royal College ofPsychiatrists, Edinburgh, June 2005.

References

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