Background. Controlled prospective studies of the simultaneous long-term outcome of several mental disorders are rare. This study sought to determine if there were important differences between the outcome of anxiety and depressive disorders after 12 years and to examine their main predictors.

Method. A cohort of 210 people seen in general practice psychiatric clinics with a DSM-III diagnosis of generalized anxiety disorder (71), panic disorder (74), or dysthymic disorder (65), including combined anxiety-depressive disorder (cothymia) (67) was followed up after 12 years. Interview assessments of symptoms, social functioning and outcome were made, the latter using a new scale, the Neurotic Disorder Outcome Scale. Seventeen baseline predictors were also examined.

Results. Data were obtained from 201 (96%) patients, 17 of whom had died. Only 73 (36%) had no DSM diagnosis at the time of follow-up. Using univariate and stepwise multiple linear regression those with cothymia, personality disorder, recurrent episodes and greater baseline self-rated anxiety and depression ratings had a worse outcome than others; initial diagnosis did not contribute significantly to outcome and instability of diagnosis over time was much more common than consistency.

Conclusion. Only two out of five people with the common neurotic disorders have a good outcome despite alleged advances in treatment. Those with greater mood symptoms and pre-morbid personality disorder have the least favourable outcome. It is suggested that greater attention be paid to the concurrent treatment of personality disorder and environmental factors rather than symptoms as these may be the real cause of apparent treatment resistance.