string: Following recovery and 1 month of mood stability (defined by mean scores of < 7 and <
   10 on the 17-item and 25-item versions of the Hamilton Depression Rating Scale (Hamilton 1960; Thase et al. 1992), respectively, and mean score of <
   7 on the BechRafaelsen Mania Scale (Bech et al. 1979, for a period of 4 weeks) patients enter in the preventative phase and are again randomized to either IPSRT or CM for maintenance treatment.