also responsible for the insertion of a "Just Say No" style drugs speech by Tasha Yar (Denise Crosby) to Wesley Crusher (Wil Wheaton), which came over the objections from the cast. Guest stars in this episode included two who had previously appeared in Star Trek II: The Wrath of Khan (1982), as Sobi and T'Jon were played by Judson Scott and Merritt Butrick respectively. Butrick had also appeared in Star Trek III: The Search for Spock; on both occasions he portrayed David Marcus, the son of Captain James T. Kirk. Butrick, who was suffering from AIDS, was unable to afford health insurance, and was offered the role as a way of helping him. He died of AIDS less than a year after filming this episode. Director Win Phelps recalled that there were numerous continuity issues throughout filming, with character motivations changing from one scene to the next. Because of changes to the script, the actors were often acting scenes that they had not seen the script for before the first take. "Symbiosis" was filmed after "Skin of Evil", which featured the death of Tasha Yar, making this the final filmed episode with Denise Crosby as Yar until she reappeared in "Yesterday's Enterprise". Towards the end of the episode, as Picard and Crusher leave the cargo bay, Crosby can be seen waving goodbye to the camera behind them. LeVar Burton later used behind the scenes footage from this episode in a feature on his show Reading Rainbow, in the episode "The Bionic Bunny Show". Reception "Symbiosis" aired in broadcast syndication during the week commencing April 22, 1988. It received Nielsen ratings of 10.8, reflecting the percentage of all households watching the episode during its timeslot. This was the highest ratings received by the series since the broadcast of "Too Short a Season" during the preceding February. The ratings received by "Symbiosis" were not beaten until the first episode of the second season, "The Child". "Symbiosis" first aired in broadcast syndication within the United States on April 18, 1988. Several reviewers re-watched the episode after the end of the series. Zack Handlen reviewed the episode for The A.V. Club in May 2010. He felt that the drug use allegory could have been better refined but praised the performance of Patrick Stewart and gave the episode an overall grade of a B. Keith DeCandido watched the episode for Tor.com, and described it as