A total of 17 RCTs (n=2,819) were included in the review.
Adherence (13 studies).
Four of 8 RCTs in patients with depression reported an increase in adherence, ranging from 11 to 30%. Both RCTs reporting this outcome in general psychiatric patients reported an increase in adherence, though neither study in patients with schizophrenia found any such difference.
Knowledge.
Eight RCTs measured knowledge using questionnaires. Between-group gains in knowledge ranged from 14 to 28%. However, knowledge questionnaires were heterogeneous between studies and the relationship between gains in knowledge and other outcomes were not investigated.
Economic outcomes.
No studies evaluated economic outcomes.
Clinical outcomes.
Six studies reported side-effects in depression. Only one showed a significant difference between groups, favouring additional written information.
Four studies provided data on admissions or relapses. None reported a significant difference between the groups.
Two studies reported symptoms or severity of illness in patients with depression. One found a significant improvement in overall effect; the second found no overall effect, but an improvement with counselling in a subgroup of patients with major depressive disorder.
Humanistic outcomes.
One study reported a statistically significant improvement in satisfaction for community patients receiving a patient information leaflet in addition to usual advice; this improvement was not significant in acute patients.
Two studies assessed quality of life. One reported a statistically significant increase over follow-up, without reporting any between-group data. The second study reported no overall differences in quality of life.