The effect on length of sickness absence by recognition of undetected psychiatric disorder in long-term sickness absence. A randomized controlled trial.

Background: The burden caused by psychiatric disorders on the individual and society has resulted in more studies examining interventions aimed at reducing sickness absence.

Aims: To examine if detection of undetected psychiatric disorders in long-term sickness absence (LSA) would improve the rate of return to work.

Methods: Over one year all 2,414 incident persons on LSA in a well-defined population were within one week after eight weeks of continuous sickness absence posted the Common Mental Disorders Screening Questionnaire (CMD-SQ) to screen for mental disorders. In a randomized controlled trial (RCT), of 1,121 responding participants, persons with a minimum level of psychiatric symptoms 420 were allocated to the intervention group and 416 to the control group. The intervention was a psychiatric examination including diagnostics with Present State Examination and feedback regarding treatment and rehabilitation to the participants themselves, general practitioners and the social service taking care of the participants' rehabilitation back to work. Of the 420 in the intervention group 329 (78.3%) participated in the intervention. The outcomes measure was in an intention treat analysis the rate of return to work.

Results: The rate of return to work was non-significantly lower for the intervention group than for the control group, except for persons without a psychiatric sick-leave diagnosis who were sick-listed from full time work, who showed a significantly higher rate of return to work in the intervention group.

Conclusions: The effect of interventions for return to work depends on socio-demographic characteristics. Further studies are needed regarding interventions to improve return to work.