Table 1.

Quality assessment of the included studies on the prevalence of the incubus phenomenon.

Study	1	2	3	4	5	6	7	Total
Wing et al. (19)	⊗	N/A	⊘	⊗	⊕	⊕	N/A	0
Spanos et al. (20)	⊗	N/A	⊘	⊗	⊘	⊕	N/A	−1
Fukuda et al. (21)	⊘	N/A	⊘	⊗	⊘	⊕	N/A	0
Cheyne et al. (22)	⊗	N/A	⊘	⊗	⊘	⊕	N/A	−1
Wing et al. (23)	⊕	N/A	⊕	⊗	⊘	⊕	N/A	2
Buzzi and Cirignotta (24)	⊘	N/A	⊘	⊗	⊘	⊘	N/A	−1
Cheyne and Girard (25)	⊕	N/A	⊘	⊗	⊘	⊕	N/A	1
Abrams et al. (26)	⊕	N/A	⊘	⊗	⊘	⊕	N/A	2
Ramsawh et al. (27)	⊕	N/A	⊘	⊗	⊘	⊗	N/A	0
Solomonova et al. (28)	⊗	N/A	⊘	⊗	⊘	⊕	N/A	−1
Jiménez-Genchi et al. (29)	⊕	N/A	⊕	⊗	⊘	⊕	N/A	2
Paradis et al. (30)	⊗	N/A	⊘	⊗	⊘	⊕	N/A	−1
Young et al. (31)	⊗	N/A	⊘	⊗	⊘	⊕	N/A	−1

⊕ = +1 point; ⊗ = −1 point; Ø = 0 point; N/A, not applicable.