There are several features of a symptom or illness that make it a convenient target for proponents of unconventional therapies. Subjective symptoms are more likely to be targeted than objective conditions – you don’t see many so-called “alternative” birth control treatments. Symptoms for which placebo effects alone are likely to produce the illusion of effectiveness are good targets for ineffective treatments. Symptoms that vary naturally over time also are good targets – patients are likely to seek treatment when their symptoms are maximal, which means spontaneous regression to the mean will provide an effective illusion of efficacy for any intervention. Illnesses with a substantial psychological component (such as those that are worsened by emotional stress or that are emotional, such as anxiety) are likely to benefit from non-specific effects of the therapeutic interaction, rendering the treatment itself irrelevant.
Finally, any condition or symptom for which there is currently no effective treatment provides a market ripe for exploitation.
Tinnitus has many of these features. Tinnitus describes the subjective experience of spontaneous noise perceived in one or both ears, which can be a buzzing, hiss, tone, or ringing sound. The severity of the tinnitus, its loudness, can vary over time, but perhaps more importantly the degree to which the tinnitus is bothersome can vary considerably. The sound is distracting and can have a significant impact on quality of life. Those with tinnitus can ignore the sound at times (depending on its severity), can be distracted from the sound, and may even learn through cognitive therapy to become accustomed to it. Therefore we might expect that tinnitus is amenable to placebo effects.
Finally, there is no proven effective treatment for tinnitus, which means that those who suffer from tinnitus may be desperate for a treatment. Desperation is a commodity highly prized by snake-oil salesmen.