Although marijuana has some bad effects, its main harm lies "not in the plant, but in the way a person's life can be ruined with a conviction for possession or jail imprisonment," Lester Grinspoon, associate professor of Psychiatry at the Massachusetts Mental Health Center, told a group of 125 students in the Science Center last night.

Grinspoon was one of four panelists participating in a discussion on marijuana sponsored by the University Health Services' Students Consumer Council.

No Evidence

Grinspoon, author of a book on the psychological effects of marijuana said there was no evidence to support the theory that marijuana leads to more dangerous drugs. He referred to studies done by other physicians on the psychological effects of marijuana that attempt to disprove the idea that marijuana causes brain damage, psychosis, or chromosome damage.

There are actually three species of marijuana, but laws in the United States only designate one of these species--cannabis sativa--as an illegal plant. The other two species--one of which is psychoactive--are not technically illegal, Richard E. Schultes '37, Mangelsdorf Professor of Natural Sciences, said last night.

So Strong

Schultes said marijuana is used for many different purposes in places where it is not illegal. In addition to its narcotic attributes, it is used to produce industrial oil in Russia, as a tranquilizer in Germany, as a source of hemp fiber, and as edible fruit in times of famine.

Other panel members included Haldean Dalzall, a researcher at the Sheehan Institute--a marijuana research organization in Cambridge--and William Rollins, an attorney with the Boston chapter of the National Organization for Reform of Marijuana Laws.