Summary of findings 1. Phenytoin (antiepileptic) versus placebo.
| Phenytoin (antiepileptics) versus placebo | ||||||
| Patient or population: adults with antisocial personality disorder Setting: prisons; multiple sites; USA Intervention: phenytoin (oral, 300 mg/day (am: 200 mg; pm: 100 mg) Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) |
Number of participants (studies) |
Certainty of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with phenytoin | |||||
|
Aggression Measured by: frequency of aggressive acts Follow‐up: end of 6‐week treatment course |
The mean frequency of aggressive acts per week was lower in the phenytoin group (mean = 0.33; SD = not reported) than in the placebo group (mean = 0.51; SD = not reported) | ‐ | 60 (1 RCT) |
⊕⊝⊝⊝ Very lowa | Narrative results only. Skewed summary data and completer analysis by the trial investigators (see Table 2). | |
| Reconviction | ‐ | ‐ | ‐ | ‐ | ‐ | No data available |
| Global state/functioning | ‐ | ‐ | ‐ | ‐ | ‐ | No data available |
| Social functioning | ‐ | ‐ | ‐ | ‐ | ‐ | No data available |
|
Adverse events Measured by: number of participants reporting nausea during week 1 Follow‐up: week 1 |
Study population | OR 1.00 (0.06 to 16.76) | 60 (1 RCT) |
⊕⊝⊝⊝ Very lowa | ‐ | |
| 33 per 1000 | 33 per 1000 (0 fewer; from 31 fewer to 333 more) | |||||
| The study authors reported that no side effects were detectable via blood cell counts or liver enzyme tests | ‐ | |||||
| *The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; OR: Odds ratio; SD: Standard deviation | ||||||
| GRADE Working Group grades of evidence High certainty: we are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect Very low certainty: we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect | ||||||
aEvidence downgraded three levels overall. We downgraded two levels for limitations in the design/implementation suggest the findings are at high risk of bias (from 'sequence generation' bias, 'allocation concealment' bias, 'blinding of participants' bias, 'blinding of personnel' bias and 'blinding of outcome assessors' 'incomplete outcome data' bias and 'other' bias), and one level for imprecision due to optimal information size criterion not being met (downgraded one level).