Objective: To present the case of a patient with anxiety and depressive symptoms who developed the clinical picture of stiff-person plus syndrome (SPS-plus).
Background: Before the onset of typical SPS symptoms, psychiatric symptoms (like depression and anxiety) may be prominent and as such misleading, resulting in the diagnosis of a psychiatric condition.
Method: We describe the case of a woman who initially presented with anxious depression and remained resistant to treatment with different classes of antidepressants and additional therapy with lithium and atypical antipsychotics.
Results: Evidence of neurologic dysfunction and significantly increased levels of serum autoantibodies for glutamic acid decarboxylase supported the diagnosis of SPS. The patient appeared to benefit from short-term immunosuppressive therapy with methylprednisolone.
Conclusions: The authors believe that anxious depression and SPS-plus seen in this patient are the result of the same underlying autoimmune process, together forming a unique syndrome. Anxious and depressive symptoms in SPS can be explained by alterations in GABAergic neurotransmission.