Title: The voices of heaven
Description: From back cover Tor paperback July 1995:

MAN OF TWO WORLDS

Barry di Hoa had the good life on the Moon: steady work and the love of a good woman.  But a rival slipped him a mickey, and he next awoke aboard Gerald Tscharka's ship as it neared the colony planet, Pava, eighteen lightyears away.

Pava was the frontier, complete with earthquakes, primitive conditions and hard physical work.  The local "doctor" couldn't treat Barry's little manic-depressive problem without medicine from the Moon.  And the Millenarist colonists, who thought suicide was cool fun, didn't thrill him.

Then he made friends with the leps.  The large caterpillar-like, odd-speaking gentle beasts were helping the humans fashion a life on their planet.  In their strange way, they *knew* things about Pava that might make the difference in the colony's survival.  He started to believe he could really enjoy life in this fragile paradise.  Except Tsharka was up to something bad, something that would change everything.  Barry knew only he could stop the mad captain, and the captain knew it, too.  What neither knew was whether Barry could be manic enough to do it.
Subjects: Space colonies, Fiction, Science fiction, Fiction, science fiction, general