Aripiprazole versus typical antipsychotic drugs for schizophrenia

Schizophrenia is a severe mental illness which mostly affects people in early adulthood. The symptoms of schizophrenia are perceptions without cause (hallucinations), fixed false beliefs (delusions) and/or apathy, slowing and less movement or thought. People with this condition are usually treated with antipsychotic medication but there are a significant number of people receiving this treatment who don’t respond, or develop uncomfortable adverse effects. Aripiprazole is a new medication which acts differently in the brain to other antipsychotics and may benefit people who have been resistant to treatment so far. This review compares aripiprazole to the older ‘typical’ antipsychotics.

The data for nine clinical trials containing a total of 3622 patients were analysed. In the trials of less than 12 weeks that reported improvement of general well-being and mental state, there was no statistically significant difference between typical antipsychotics and aripiprazole. However, when looking at adverse effects, people on aripiprazole were less likely to suffer from movement side effects, blurred vision, high levels of the hormone prolactin or increased heart rate. These people were also less likely to withdraw their consent to being in the study in short (less than 12 weeks) and longer (more than 12 weeks) trials. Conversely, people on typical antipsychotics were significantly less likely to feel dizzy or nauseous. These trials were all quite different from each other - they had varying settings, enrolled different groups of people, were for varying lengths of times (from 24 hours to 52 weeks) and compared aripiprazole to different first generation antipsychotics. This made it difficult to compare outcomes from trial to trial. In addition, a lot of the data were not able to be used because measurements were not given in full. This medication looks promising but there needs to be more trials, particularly longer-term well-planned trials.

(Plain language summary prepared for this review by Janey Antoniou of RETHINK, UK www.rethink.org).

Authors' conclusions: 

Aripiprazole differs little from typical antipsychotic drugs with respect to efficacy, however it presents significant advantages in terms of tolerability. Clearly reported pragmatic short, medium and long term randomised controlled trials are required to replicate and validate these findings and determine the position of aripiprazole in everyday clinical practice.

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Background: 

Aripiprazole is a relatively new antipsychotic drug, said to be the prototype of a new third generation of antipsychotics; the so-called dopamine-serotonin system stabilisers. In this review we examine how the efficacy and tolerability of aripiprazole differs from that of typical antipsychotics.

Objectives: 

To evaluate the effects of aripiprazole compared with other typical antipsychotics for people with schizophrenia and schizophrenia-like psychoses.

Search strategy: 

We searched the Cochrane Schizophrenia Group Trials Register (November 2007) which is based on regular searches of BIOSIS, CENTRAL, CINAHL, EMBASE, MEDLINE and PsycINFO. We inspected references of all identified studies for further trials. We contacted relevant pharmaceutical companies, drug approval agencies and authors of trials for additional information.

Selection criteria: 

We included all randomised trials comparing aripiprazole with typical antipsychotics in people with schizophrenia or schizophrenia-like psychosis.

Data collection and analysis: 

We extracted data independently. For dichotomous data we calculated relative risks (RR) and their 95% confidence intervals (CI) on an intention-to-treat basis, based on a random effects model. We calculated numbers needed to treat/harm (NNT/NNH) where appropriate. For continuous data, we calculated weighted mean differences (WMD) again based on a random effects model. We have contacted representatives of Bristol Myers Squibb pharmaceuticals (UK) for additional data.

Main results: 

We included nine randomised trials involving 3122 people comparing aripiprazole with typical antipsychotic drugs. None of the studies reported on relapse - our primary outcome of interest. Attrition from studies was high and data reporting poor. Participants given aripiprazole were comparable to those receiving typical drugs in improving global state and mental state. Aripiprazole provided a significant advantage over typical antipsychotics in terms of fewer occurrences of extra-pyramidal symptom (n=968, 3 RCT, RR 0.46 CI 0.3 to 0.9, NNT 13 CI 17 to 10), and particularly akathisia (n=897, 3 RCT, RR 0.39 CI 0.3 to 0.6, NNT 11 CI 14 to 9). Fewer participants given aripiprazole developed hyperprolactinaemia (n=300, 1 RCT, RR 0.07 CI 0.03 to 0.2, NNT 2 CI 3 to 1). Aripiprazole presented a lesser risk of sinus tachycardia (n=289, 1 RCT, RR 0.09 CI 0.01 to 0.8, NNT 22 CI 63 to 13) and blurred vision (n=308, 1 RCT, RR 0.19 CI 0.1 to 0.7, NNT 14 CI 25 to 10); but enhanced risk of occurrence of dizziness (n=957, 3 RCT, RR 1.88 CI 1.1 to 3.2, NNH 20 CI 33 to 14) and nausea (n=957, 3 RCT, RR 3.03 CI 1.5 to 6.1, NNH 17 CI 25 to 13). Attrition rates were high in both groups, although significantly more participants in the aripiprazole group completed the study in the long term (n=1294, 1 RCT, RR 0.81 CI 0.8 to 0.9 NNT 8 CI 5 to 14).

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