“…Later studies confirming the unidimensionality and clinical usefulness of this subscale suggested that the HAM-D6 is better suited to assess severity and response to treatment than the HAM-D (Bech et al, 1981;Licht et al, 2005) and indicated that the HAM-D6 has biological validity (Østergaard et al, 2014). Bech et al considered these six items (depressed mood, feelings of guilt, work and interests, psychomotor retardation, psychic anxiety, and tiredness/pain) as representing the nuclear symptoms of depression, while nine other items (HAM-D9: three insomnia items, agitation, somatic anxiety, loss of appetite, genital symptoms, hypochondriasis, and weight loss) evaluate unspecific arousal responses to stress; the remaining two items (HAM-D2) evaluate suicide thoughts and lack of insight (Bech, 2011).…”