Background: This study aimed to replicate findings that length of episode prior to adequate antidepressant treatment (the 'no-treatment interval') and premorbid neuroticism predict time to remission from the institution of adequate treatment for depression.
Methods: Eighty-three inpatients meeting ICD-10 criteria for a depressive illness were entered into an 18-month prospective follow-up study of illness course. Subjects were assessed using the Schedules for Clinical Assessment in Neuropsychiatry, Maudsley Personality Inventory (MPI) and the Hamilton Rating Scale for Depression (HRSD). Remission was defined as an HRSD score of < 8 for 2 consecutive weeks.
Results: Twenty-two patients (27%) remained depressed 12 months after the onset of adequate treatment. Significantly longer times to remission were predicted by a longer no-treatment interval and higher premorbid neuroticism scores.
Limitations: Adequate antidepressant treatment was commenced prior to admission in half the cases, requiring a retrospective assessment of illness course prior to study entry. Twenty-four patients (29%) had not remitted at the time of completion of the MPI.
Conclusions: These results replicate previous findings identifying a longer time to treatment and higher neuroticism scores as predictors of chronicity in depression.