Table 3 Results of multilevel analyses: Assessment (t0-t1) vs. standard treatment (t1-t3) vs. extended treatment (t3-t10)

CY-BOCS-D rating scale

38

− 0.34^a (− 0.69 to 0.01)

− 0.48

− 0.54***^b,c (− 0.72 to − 0.36)

− 1.53

− 0.42***^a,c (− 0.61 to − 0.24)

− 1.19

− 0.05^b,d (− 0.25 to 0.16)

− 0.14

− 0.08^b,d (− 0.33 to 0.16)

− 0.23

− 0.06^a,c (− 0.62 to 0.49)

− 0.09

Obsession severity

38

− 0.18^a (− 0.40 to 0.04)

− 0.25

− 0.23***^a,c (− 0.35 to − 0.12)

− 0.66

− 0.17**^a,c (− 0.28 to − 0.05)

− 0.47

− 0.07^a,d (− 0.19 to 0.06)

− 0.18

0.01^b,d (− 0.14 to 0.16)

0.03

− 0.13^a,c (− 0.47 to 0.21)

− 0.18

Compulsion severity

38

− 0.18*^a (− 0.36 to − 0.00)

− 0.49

− 0.29***^b,c (− 0.38 to − 0.20)

− 1.56

− 0.22***^a,c (− 0.32 to − 0.13)

− 1.21

0.01^b,d (− 0.09 to 0.11)

0.05

− 0.06^b,d (− 0.18 to 0.07)

− 0.31

− 0.05^a,c (− 0.32 to 0.23)

− 0.12

OCD-CA

Total OCD symptoms

[31]

[− 0.32^a] [(− 1.20 to 0.56)]

[− 0.11]

[− 0.53*^a,c] [(− 0.97 to − 0.10)]

[− 0.38]

[− 0.65**^a,c] [(− 1.09 to − 0.21)]

[− 0.46]

[− 0.42^a,c] [(− 0.91 to 0.06)]

[− 0.30]

[− 0.03^a,c] [(− 0.59 to 0.53)]

[− 0.02]

[0.70^a,c] [(− 0.61 to 2.01)]

[0.25]

{37}

{− 0.72^a} {(− 1.48 to 0.04)}

{− 0.25}

{− 0.56**^a,c} {(− 0.96 to − 0.16)}

{− 0.40}

{− 0.73***^a,c} {(− 1.13 to − 0.32)}

{− 0.51}

{− 0.03^b,d} {(− 0.48 to 0.43)}

{− 0.02}

{− 0.09^b,c} {(− 0.62 to 0.45)}

{− 0.06}

{0.25^a,c} {(− 0.98 to 1.49)}

{0.09}

OCD-related problem list

Frequency

[31]

[− 0.04*^a] [(− 0.08 to − 0.00)]

[− 0.23]

[− 0.05***^a,c] [(− 0.06 to − 0.04)]

[− 0.57]

[− 0.04***^a,c] [(− 0.05 to − 0.03)]

[− 0.47]

[− 0.02***^b,d] [(− 0.03 to − 0.01)]

[− 0.25]

[− 0.01^b,d] [(− 0.03 to 0.00)]

[− 0.17]

[0.06**^b,d] [(0.02 to 0.10)]

[0.36]

{32}

{− 0.01^a} {(− 0.05 to 0.04)}

{− 0.04}

{− 0.06***^b,c} {(− 0.08 to − 0.04)}

{− 0.90}

{− 0.04***^b,d} {(− 0.06 to − 0.02)}

{− 0.62}

{0.00^a,d} {(− 0.02 to 0.02)}

{− 0.05}

{− 0.01^a,d} {(− 0.03 to 0.01)}

{− 0.16}

{− 0.02^a,c} {(− 0.08 to 0.05)}

{− 0.14}

Strain

[31]

[− 0.12**^a] [(− 0.21 to − 0.03)]

[− 0.39]

[− 0.07***^b,c] [(− 0.10 to − 0.04)]

[− 0.46]

[− 0.11***^a,d] [(− 0.14 to − 0.09)]

[− 0.73]

[− 0.04**^b,c] [(− 0.07 to − 0.01)]

[− 0.28]

[− 0.01^b,d] [(− 0.05 to 0.02)]

[− 0.09]

[0.01^b,d] [(− 0.05 to 0.16)]

[0.18]

{32}

{− 0.13*^a} {(− 0.25 to − 0.01)}

{− 0.49}

{− 0.11***^a,c} {(− 0.15 to − 0.06)}

{− 0.81}

{− 0.10***^a,c} {(− 0.14 to − 0.06)}

{− 0.77}

{0.00^b,d} {(− 0.04 to 0.05)}

{0.04}

{− 0.03^b,d} {(− 0.09 to 0.03)}

{− 0.25}

{0.09^b,d} {(− 0.07 to 0.25)}

{0.34}

Psychosocial impairment

[30]

[− 0.06***^a] [(− 0.10 to − 0.03)]

[− 0.36]

[− 0.03***^b,c] [(− 0.04 to − 0.02)]

[− 0.36]

[− 0.02***^b,c] [(− 0.03 to − 0.01)]

[− 0.25]

[− 0.01^b,d] [(− 0.02 to 0.01)]

[− 0.06]

[0.00^b,d] [(− 0.01 to 0.01)]

[0.00]

[0.00^b,c] [(− 0.03 to 0.04)]

[0.03]

{36}

{− 0.03^a} {(− 0.07 to 0.01)}

{− 0.26}

{− 0.05***^b,c} {(− 0.07 to − 0.04)}

{− 0.82}

{− 0.02*^b,d} {(− 0.03 to − 0.00)}

{− 0.28}

{0.00^b,d} {(− 0.02 to 0.02)}

{0.05}

{0.00^b,d} {(− 0.02 to 0.03)}

{0.04}

{− 0.04^a,c} {(− 0.10 to 0.02)}

{− 0.29}

OCD-functional impairment list

Total psychosocial impairment

[30]

[− 1.35***^a] [(− 1.64 to − 1.05)]

[− 0.57]

[− 0.36***^b,c] [(− 0.46 to − 0.27)]

[− 0.31]

[− 0.26***^b,d] [(− 0.35 to − 0.18)]

[− 0.22]

[− 0.10*^b,d] [(− 0.19 to − 0.01)]

[− 0.09]

[− 0.17**^b,d] [(− 0.28 to − 0.05)]

[− 0.14]

[0.27^b,d] [(− 0.08 to 0.61]

[0.11]

{35}

{− 1.52***^a} {(− 2.01 to − 1.03)}

{− 0.80}

{− 0.56***^b,c} {(− 0.75 to − 0.37)}

{− 0.59}

{− 0.19*^b,d} {(− 0.38 to 0.00)}

{− 0.20}

{− 0.03^b,d} {(− 0.25 to 0.18)}

{− 0.04}

{− 0.43**^b,c} {(− 0.70 to − 0.16)}

{− 0.45}

{0.13^b,c} {(− 0.60 to 0.86)}

{0.07}