| Methods |
Design: five group parallel trial
Purpose: examine the effect of paradoxical intention therapy on insomnia |
| Participants |
Patients: out‐patients suffering from insomnia
Baseline comparability: yes (sleep parameters) |
| Interventions |
Placebo: sessions of 'quasi‐desensitization' (neutral images paired with bedtime activity)
Untreated: no sessions (waiting list)
Experimental: sessions of
‐paradoxical intention therapy: instructions to remain awake as long as possible and presented with the true theoretical background
‐stimulus control: practical advice on bed time activities
‐progressive relaxation: training in relaxation techniques
(Co‐intervention: hypnotics, comparable doses between groups) |
| Outcomes |
Sleep latency (min)
Returning to sleep difficulty
Restedness rating
Falling asleep difficulty
Hours of sleep
Drug usage per week |
| Notes |
|
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Blinding?
Treatment provider |
High risk |
Not described as double‐blind (placebo/paradoxical intention) |
| Blinding?
Outcome assessor |
Unclear risk |
Not relevant as patient reported outcome |
| Incomplete outcome data addressed?
All outcomes |
High risk |
|
| Free of selective reporting? |
Unclear risk |
No protocol available |
| Free of other bias? |
Low risk |
|
| No signs of variance inequality or skewness? |
High risk |
Either variance inequality (F‐test statistically significant) or skewness (1.64 standard deviations exceeds the mean) |
| Trial size > 49? |
High risk |
N = 20 |
| Clearly concealed allocation + trial size > 49 + drop‐out max 15% |
High risk |
Trial size < 49 |
