retrogress
     v 1: get worse; fall back to a previous or worse condition [syn:
          {regress}, {retrograde}] [ant: {progress}]
     2: go back to bad behavior; "Those who recidivate are often
        minor criminals" [syn: {relapse}, {lapse}, {recidivate}, {regress},
         {fall back}]
Source: WordNet® 2.0