A party seeking a new trial on an alternative case must demonstrate that the alternative case was properly put at trial and supported by expert evidence; lay witness evidence alone, even if improperly rejected by the trial judge, cannot support a psychiatric diagnosis requiring clinical assessment under the DSM-IV. An expert opinion that something 'may have' caused something else permits but does not require the tribunal of fact to find causation established on the balance of probabilities. Where a more serious psychiatric consequence (PTSD) is admitted to be reasonably foreseeable, a lesser consequence (alcoholism) should also be regarded as reasonably foreseeable.
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