Serotonin-specific reuptake inhibitors (SSRIs) are generally considered safe drugs but fatal adverse effects do sometimes occur, often as a consequence of interactions with other serotonin active drugs. Polypharmacy is usually a problem that the elderly encounter, but it can also have dire consequences for young people, especially when an underlying heart condition is present. Thus, failure to diagnose heart disease and the use of contraindicated medications can be a lethal combination, irrespective of age. Here we present a case of a young adult suffering from bipolar disorder who used a combination of two SSRIs (citalopram and fluoxetine) and a monoamine oxidase inhibitor (MAO; moclobemide) with tragic consequences. The deceased also suffered from undiagnosed hypertrophic cardiomyopathy and was carrier of a genotype that may have predisposed him to increased sensitivity to SSRIs. The apparent difficulty in establishing the manner of death in this case is also discussed.