Purpose Psychotropic drug consumption as a proxy measure of mental health problems during a disability pension process has only been studied among awarded applicants. This study examined psychotropic drug purchase trajectories among awarded and rejected disability pension applicants. Analyses were conducted in different diagnostic and sociodemographic groups. Methods A representative 70% sample of Finnish adults applying for disability pension due to a mental disorder in 2009-2011 (N = 18,087) was followed for 4 years in 3-month periods both before and after the pension decision. Register data on purchased drugs measured in defined daily doses (DDDs), gender, age, occupational class, unemployment history, and diagnostic group were used. The DDD levels and trends were analyzed using growth curve models. Results Psychotropic drug purchases increased before the pension decision and decreased gradually thereafter among both awarded and rejected applicants. The average DDD level was higher for rejected than awarded applicants before the decision but lower thereafter. The high pre-decision level for rejected applicants was explicit with a lower socioeconomic status. The pre-decision increase in DDDs was steeper for awarded applicants. Changes in DDDs before and after the decision were most prominent for depression, bipolar disorders, schizophrenia, and anxiety disorders. Conclusion Awarded and rejected disability pension applicants differed partly in their trajectories of psychotropic drug consumption. For awarded applicants, the steep rise of consumption prior to the award possibly reflects worsening occupational capacity. Early high consumption for rejected applicants signals long running mental health problems and calls for earlier support.