BACKGROUND Primary focal hyperhidrosis (PFH) is defined as excessive sweating typically localized to specific body areas such as axillae, hands and feet. An association between PFH and anxiety as well as depressive syndromes has been suggested. OBJECTIVES To investigate a possible association between PFH and anxiety, depression, social phobia and quality of life, and to study the effect of treatment with botulinum toxin A on these factors. METHODS PFH was confirmed clinically and by gravimetry. To measure anxiety and depressive syndromes several German versions of standardized questionnaires were used: State-Trait Anxiety Inventory G Form X2 (STAI), Social Phobia Scale (SPS), Symptom Checklist of Derogatis (SCL-90-R), subscales 'Social Insecurity', 'Depression', 'Anxiety' and 'Phobia', and Hospital Anxiety and Depression Scale (HADS-D). Quality of life was assessed using Skindex. Two analyses were performed. The first analysis included all patients with PFH, the second analysis only patients with PFH who were treated with botulinum toxin A. In the latter group the questionnaires were repeated 2-4 weeks after treatment. RESULTS For the total group at baseline the values for STAI, SCL-90-R, HADS-D and SPS were well within the normal range. However, in the group of patients treated with botulinum toxin A, the mean +/- SD SPS score was 17.6 +/- 15.5, i.e. above the normal range. Quality of life was impaired, with a mean +/- SD Skindex score of 24.3 +/- 5.7 at baseline. Treatment with botulinum toxin A led to a significant reduction in all investigated symptoms. CONCLUSIONS Despite an impaired quality of life, patients with PFH in general do not show increased symptoms of anxiety, depression or social phobia. Only in the subgroup of patients treated with botulinum toxin A was the SPS increased at baseline. Treatment with botulinum toxin A led to a marked improvement in all factors investigated.