The Voice of Depression: Prevalence and Stability Across Time of Perception-Laden Intrusive Thoughts in Depression

Abstract
Intrusive depressive thoughts are typically defined in terms of their content, frequency, and pervasiveness. The extent to which they carry sensory properties is largely unexplored. In a pilot study, 56.5% of individuals with mild to moderate depressive symptoms experienced depressive thoughts with sensory features. The present study explored the prevalence of sensory thoughts in patients with severe depression and examined the stability of the sensory phenomena across time. A total of 163 participants with severe depression completed an online assessment at baseline and 3 months later. Diagnostic status was established at baseline over the tel- ephone. The primary outcome was the Sensory Properties of Depressive Thoughts Questionnaire (SPD). The frequency of sensory properties of negative thoughts was similar (60.7% reported at least one sensory irritation; thus, 39.3% of the sample reported not a single, even mild sensory irritation) to the pilot study. The highest prevalence was observed for bodily sensations (41.1%; pilot: 39.6%) followed by auditory (37.4%; pilot: 30.6%) and visual (31.3%; pilot: 27.2%) perceptions. Prevalence remained essentially unchanged over time, but test–retest reliability was weak to moderate (r = .56). Unlike in the pilot study, no association emerged with quality of life and suicidality. Yet, those reporting sensory phenomena were prescribed more medication, had a similar num- ber of prior hospitalizations despite their younger age, were more frequently in psychotherapy (statistical trend), and had more pain symptoms, which tentatively suggests a more complicated course of illness. Replication in independent samples is needed. Our findings support the notion that depressive thoughts are not “silent” but are commonly accompanied by sensory experiences.