This is a case report of a gentleman with an intellectual impairment who presented with both hereditary spastic paraplegia (HSD) and bipolar affective disorder (BPAD), a combination that has not yet been described in the professional literature. A limited number of articles have suggested an association between HSP and an organic personality disorder. We describe the case of a gentleman who was diagnosed with BPAD in his early adult life and displayed neurological symptoms of HSP at around the same time. Diagnosis of both HSP and BPAD can be difficult and is further compounded by an intellectual impairment. Treatment options may be limited by the propensity of many psychotropic medications to cause movement disorders and thus worsening neurological symptoms.