My sister, who lives in Holland, is a Parkinson’s patient who is treating her condition with marijuana - or derivatives of it. In the last couple of months, Dutch doctors have been allowed to prescribe marijuana-based medication for Parkinson’s, and my sister has taken advantage of this change in the law.

Several products are available, including Marinol, a synthetic form of THC (tetrahydrocannabiol), the active ingredient of marijuana. This US-made product is expensive - 10 capsules cost 86 euros (£60) - and is not yet approved for Parkinson’s. It has so far been tested only on AIDS and MS patients.

Nonetheless, my sister has started to show spectacular results. She now has clarity of mind, she can turn around in bed by herself and doesn’t have to wake her husband to help her get out of bed. Her stiffness has gone and she is no longer an invalid; her sense of coordination has improved and she can cycle again. The tremor has not disappeared, but is much less.

She has substantially reduced her medication (Sinemet, Comtan, Requip, Sifrol and Diazepam), which has helped to reduce side-effects. In fact, she now suspects that the concoction of drugs, rather than the disease itself, has been responsible for many of her symptoms.

Because of the high cost of Marinol, she has begun using marijuana itself, which is available legally for medicinal purposes in Holland, and can be obtained on prescription from chemists, though currently, this provision is available only for patients with AIDS, MS, Alzheimer’s or cancer. For the moment, my sister can only obtain marijuana from an organisation that sells it to its members.

She has also decided to experiment by brewing a tea from it. Tea made from either Marinol or the marijuana plant seems to work, at least for her. Neither functions as a sedative, but they both relax the muscles, so any tremor is less severe and she is sleeping better. - Nina van Moorsel, via e-mail