OBJECTIVE: There are case reports about antidepressants causing arthritis and arthralgia, and the majority of these reports deal with atypical antidepressants, which are serotonin receptor 2A (5-HT(2A))-blocking substances. The aim of this study was to examine a possible association between joint disorders and the use of 5-HT(2A)-blocking atypical antidepressants. METHODS: We performed a retrospective study using reports of adverse drug reactions (ADRs) of 5-HT(2A)-blocking atypical antidepressant substances concerning joint disorders reported to the Swedish Adverse Drug Reactions Committee and the World Health Organization (WHO) Adverse Reactions Database during the period January 1, 1990 to December 31, 2006. The reports of joint disorders were related to sales figures measured as defined daily doses and to the total number of ADR reports. RESULTS: In the Swedish material, the 5-HT(2A) antagonists were 45 times more often reported to give joint ADRs when related to sales figures and compared with the selective serotonin reuptake inhibitors (SSRIs; P