Few data exist examining the longer-term outcome of bulimia nervosa (BN) following treatment with cognitive behavioral therapy (CBT) and exposure with response prevention (ERP).

One hundred and thirty-five women with purging BN received eight sessions of individual CBT and were then randomly assigned to either relaxation training (RELAX) or one of two ERP treatments, pre-binge (B-ERP) or pre-purge cues (P-ERP). Participants were assessed yearly following treatment and follow-up data were recorded.

Eighty-one per cent of the total sample attended long-term follow-up. At 5 years, abstinence rates from binging were significantly higher for the two exposure treatments (43% and 54%) than for relaxation (27%), with no difference between the two forms of exposure. Over 5 years, the frequency of purging was lower for the exposure treatments than for relaxation training. Rates of recovery varied according to definition of recovery. Recovery continued to increase to 5 years. At 5 years, 83% no longer met DSM-III-R criteria for BN, 65% received no eating disorder diagnosis, but only 36% had been abstinent from bulimic behaviors for the past year.

This study provides possible evidence of a conditioned inoculation from exposure treatment compared with relaxation training in long-term abstinence from binge eating at 5 years, and the frequency of purging over 5 years, but not for other features of BN. Differences among the groups were not found prior to 5 years. CBT is effective for BN, yet a substantial group remains unwell in the long term. Definition of recovery impacts markedly on recovery rates.