Table 1 Characteristics and results of included primary studies and meta-analyses

Berk et al. (2011)

Meta-analysis of 12 Lilly funded RCTs

4346

Symptomatic response and relapse using manic symptoms, depression, and global impression

Increased response comparing 1–5 episodes with >10 episode groups in treatment of depression, mania, and maintenance studies

Scott et al. (2007)

Meta-analysis of RCTs

716

Relapse rates

Psychological adjuncts were more effective in patients who had experienced less episodes

Colom et al. (2010)

Patients from the Bipolar Disorders Program at the Hospital Clinic of Barcelona

120

Time to recurrence

Increased response to treatment in people with fewer previous episodes, particularly if less than seven

Dion et al. (1988)

Patients from the clinical evaluation unit of McLean hospital, USA

67

Functioning via the modified vocational status index and modified location code index scales

At follow-up, the first admission had increased rates of employment vs the previous admissions (64 vs 33 %)

Admission number not significant in explaining employment in multiple regression

Franchini et al. (1999)

Outpatient Lithium Clinic for Mood Disorders, Milan

270 in total

171 with bipolar disorder

Recurrence rates

Initiating lithium therapy during the first 10 years of bipolar onset results in less recurrence

Jiang (1999)

Acute psychiatric service Taiwan

63

Vocational and residential functioning

The first admission (70.2 %) vs multiple admission (31.8 %) employed and able to live independently at follow-up

Effect not significant in multiple regression explaining outcome

Keck et al. (1995)

Patients from the University of Cincinnati Hospital psychiatric units

71

Symptomatic and syndromal outcomes in manic symptoms, depression, global assessment of functioning, and comorbidity

The first episode (using the first admission as proxy) mania associated with shorter hospital stays compared with multiple episode patients

Rosa et al. (2012)

Patients at Santiago Apostol Hospital and in the Bipolar Disorders Program at Hospital Clinic of Barcelona

119

Psychosocial functioning

Treatment of patients in the first episode (using the first admission as proxy) resulted in improved symptomatic and psychosocial outcomes in comparison to patients treated in later episodes, even after controlling for the effects of age and affective symptoms

Tohen et al. (2010)

Inpatients and outpatients initiating or changing oral medication for treatment of acute mania

3115

Recovery, response and remission using clinical global impression, mania symptoms, and depression

Patients treated in their first episode of bipolar reached recovery or remission more often and faster at 12 weeks compared with patients experiencing a later episode

Swann et al. (1999)

Inpatients

154

Response to anti-manic medication

Increased response to treatment for patients who had experienced fewer episodes, particularly if less than ten