Cross-National Collaborative Group

Weissman MM, Bland RC, Canino GJ, Greenwald S, Hwu HG, Lee CK, Newman SC, Oakley-Browne MA, Rubio-Stipec M, Wickramaratne PJ, et al (1994) The cross national epidemiology of obsessive-compulsive disorder The Cross National Collaborative Group. J Clin Psychiatry 55 (Suppl) 5-10... 

Christensen O, Christensen E. Fat consumption and schizophrenia. Acta Psychiatr Scand 1988 78 587-591. Cross National Collaborative Group. The changing rate of major depression crossnational comparisons,... 

This group includes compounds with actions on a range of neurotransmitter systems. Their antidepressant efficacy is mediated by reuptake inhibition of serotonin and noradrenaline, although side-effects such as sedation may also be useful. Their use in anxiety disorders is supported by a long history of clinical experience and a reasonable evidence base from controlled trials. Studies support the use of clomipramine (a potent serotonin reuptake inhibitor) in panic disorder and OCD (Lecrubier et al. 1997 Clomipramine Collaborative Study Group 1991), of imipramine in panic disorder and GAD (Cross-National Collaborative Panic Study 1992 Rickels et al. 1993), and of amitriptyline in PTSD (Davidson et al. 1993a). No controlled studies support the use of TCAs in social anxiety disorder. 

Short-Term Efficacy Although at least one study found no difference between alprazolam and placebo, several short-term studies have reported that alprazolam reduces the frequency and intensity of panic attacks (19, 20, 21, 22, 23, 24, 25, 26 and 27) (Table 13-2). In phase I of a cross-national collaborative study, including approximately 500 patients at eight sites, alprazolam was superior to placebo at the end of week 1 in improving spontaneous and situational panic attacks, anxiety, and secondary disability ( 23). At week 4, 50% of alprazolam patients and 28% of placebo patients were free of panic attacks. At week 8, however, 50% of those on placebo were also free of panic attacks, compared with 59% of those receiving alprazolam. These data reflect group efficacy and not individual responses over time. Furthermore, there was considerable variability and, at times, instability of response in individual patients. Explanations offered for the high rate of placebo response in this and other studies include ... 

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