Thirteen patients with stiff-man syndrome (SMS) were studied with the Minnesota Multiphasic Personality Inventory (MMPI), the Self-Administered Alcoholism Screening Test (SAAST), the State-Trait Anxiety Inventory (STAI) profiles, and by telephone interview's. The mean MMPI, SAAST, and STAI were within normal limits: however; several patients had abnormal profiles. The results of telephone interviews revealed that 8 patients (62%) had been given at least 1 psychiatric diagnosis and 4 (31%) abused alcohol ol were dependent on it, Two patients had a psychiatric diagnosis that preceded the onset of symptoms of SMS. The authors hypothesize that SMS patients have a gamma-aminobutyric ic acid deficiency or GABAergic neuron dysfunction that leads to psychiatric symptoms, including depression and chemical abuse. Clinicians treating patients with SMS must be alert to the possible presence of comorbid psychiatric illnesses in this patient population.