A federal jury in Cheyenne, Wyo., ordered SmithKline Beecham (now GlaxoSmithKline) to pay $6.4 million to relatives of Donald Schell.

Schell, 60, had been taking Paxil for just 48 hours when he shot and killed his wife, his daughter, his granddaughter and himself.

The June 7 verdict may alter the landscape in a mass tort that had struggled to gain traction.

Although plaintiffs' lawyers had filed hundreds of cases against the manufacturers of the three leading antidepressants, all but three of those suits were dismissed or settled. The first two cases to reach trial - both against the makers of Prozac - ended in defense verdicts.

But now, with the dramatic victory in the Paxil case, plaintiffs' lawyers say the drug companies will be more willing to settle and will face a tougher road when they take cases to court.

According to Andy Vickery, who tried the case for the plaintiffs, the verdict lays firm groundwork for future cases involving Paxil because the Wyoming jury found the medication could cause someone to commit suicide or homicide. He also believes the verdict is bad news for makers of the other two antidepressants which will be implicated by association.

"On a fundamental gut level, this is going to make all these people very nervous," says Vickery, partner in a four-lawyer Houston firm.

All three drugs are SSRIs (selective serotonin reuptake inhibitors) which control depression by preventing the brain from reabsorbing serotonin, a chemical which is produced naturally to control mood, sleep and appetite.