Table 2 Summary of findings per subjective wellbeing constructs, methadological quality index

Depression (23 studies)

Cross-sectional: 16 studies [4, 57,58,59,60,61,62,63,64,65,66,67, 88, 93, 95, 97].

Fourteen studies found a significant benificial association between friendship quality and depressive symptoms, while two found no association.

6–15

Longitudinal: 6 studies [83,84,85,86, 92, 94, 98].

Four studies found a significant beneficial relationship between friendship quality and depressive symptoms; two studies found a bidirectional relationship; and one study found no effect.

12–14

Case- Control: 1 study [56].

The study found no significant association between friendship quality and depressive symptoms, neither in adolescents with Asperger’s syndrome nor in typically developed groups.

7

Loneliness (10 studies)

Cross-sectional: 8 studies [62, 67,68,69,70,71,72, 93].

Seven studies found a significant beneficial association between friendship quality and loneliness, while only one study found no effect.

8–15

Case-control: 2 studies [55, 56].

One study found a significant beneficial association between friendship quality and loneliness among typically-developed adolescents but not among adolescents with Asperger’s syndrome, while the other study showed that lonileness score was higher among adolescents with ASD who had poor peer relationships.

7–8

Life satisfaction (8 studies)

Cross-sectional: 7 studies [73,74,75,76,77, 89, 91].

All seven studies found a significant positive association between the quality of friendships and life satisfaction.

8–10

Longitudinal: 1 study [90].

The study found a significant positive longitudinal association between friendship quality and life satisfaction.

13

Self-esteem (6 studies)

Cross-sectional: 6 studies [66, 67, 78,79,80, 87, 93].

All but one study found a significant positive association between the friendship quality and self-esteem.

7–10

Happiness (5 studies)

Cross-sectional: 4 studies [63; 74; 69, 60].

All four studies found a significant positive association between friendship quality and happiness.

8–11

Longitdinal: 1 study [83, 86].

The study found a significant positive longitudinal association between friendship quality and happiness.

13

Subjective wellbeing (5 studies)

Cross-sectional: 4 studies [78, 79, 82, 91]

All four studies found a significant positive association between friendship quality and subjective wellbeing.

9

Longitudinal: 1 study [96].

The study found no significant longitudinal association between friendship quality and happiness.

12