: 21 Since 2003, a number of studies have reported fluoxetine-induced impacts on a number of behavioural and physiological endpoints, inducing antipredator behaviour, reproduction, and foraging at or below field-detected concentrations. However, a 2014 review on the ecotoxicology of fluoxetine concluded that, at that time, a consensus on the ability of environmentally realistic dosages to affect the behaviour of wildlife could not be reached. At environmentally realistic concentrations, fluoxetine alters insect emergence timing. Richmond et al., 2019 find that at low concentrations it accelerates emergence of Diptera, while at unusually high concentrations it has no discernable effect.Several common plants are known to absorb fluoxetine. Several crops have been tested, and Redshaw et al. 2008 find that cauliflower absorbs large amounts into the stem and leaf but not the head or root. Wu et al. 2012 find that lettuce and spinach also absorb detectable amounts, while Carter et al. 2014 find that radish (Raphanus sativus), ryegrass (Lolium perenne) – and  Wu et al. 2010 find that soybean (Glycine max) – absorb little. Wu tested all tissues of soybean and all showed only low concentrations. By contrast various Reinhold et al. 2010 find duckweeds have a high uptake of fluoxetine and show promise for bioremediation of contaminated water, especially Lemna minor and Landoltia punctata. Ecotoxicity for organisms involved in aquaculture is well documented. : 275–276  Fluoxetine affects both aquacultured invertebrates and vertebrates, and inhibits soil microbes including a large antibacterial effect. For applications of this see § Other uses.
Statistical analyses conducted by two independent groups of FDA experts found a 2-fold increase of the suicidal ideation and behavior in children and adolescents, and 1.5-fold increase of suicidality in the 18–24 age group. The suicidality was slightly decreased for those older than 24, and statistically significantly lower in the 65 and older group. This analysis was criticized by Donald Klein, who noted that suicidality, that is suicidal ideation and behavior, is not necessarily a good surrogate marker for suicide, and it is still possible, while unproven, that antidepressants may prevent actual suicide while increasing suicidality. In February 2018, the FDA ordered an update to the warnings based on statistical evidence from twenty four trials in which the risk of such events increased from two percent to four percent relative to the placebo trials.On 14 September 1989, Joseph T. Wesbecker killed eight people and injured twelve before committing suicide. His relatives and victims blamed his actions on the Prozac medication he had begun taking a month prior. The incident set off a chain of lawsuits and public outcries. Lawyers began using Prozac to justify the abnormal behaviors of their clients. Eli Lilly was accused of not doing enough to warn patients and doctors about the adverse effects, which it had described as "activation", years prior to the incident.There is less data on fluoxetine than on antidepressants as a whole. In 2004, the FDA had to combine the results of 295 trials of 11 antidepressants for psychiatric indications to obtain statistically significant results.