Consequences of bullying victimization in childhood and adolescence: A systematic review and meta-analysis

Table 1 Associations between bullying victimization in children and adolescents and mental health outcomes

	Data points	Pooled OR	95%CI lower bound	95%CI upper bound	Cochran’s Q	I² (%)	Test for heterogeneity (P value)
Poor mental health
Pooling all	39	1.6	1.42	1.81	303.79	87.49	< 0.01
Study type
Retrospective/cross-sectional	25	1.8	1.44	2.25	211.78	88.67	< 0.01
Prospective cohort	14	1.39	1.29	1.49	22.12	41.24	0.05
Sex
Male	3	2.49	1.86	3.32	0.44	0	0.8
Female	3	2.38	1.41	4	6.95	71.22	0.03
Twins	3	1.41	1.27	1.56	2.5	20.09	0.29
Severity of bullying
Sometimes	8	1.5	1.27	1.76	47.68	85.23	< 0.01
Frequent	8	1.52	1.18	1.95	51.4	86.38	< 0.01
Anxiety
Pooling all	58	1.77	1.34	2.33	3816.23	98.51	< 0.01
Anxiety	32	1.56	1.39	1.75	434.61	92.87	< 0.01
Social phobia	8	2.48	1.59	3.86	11.01	36.41	0.14
Generalised anxiety disorder	2	2.83	1.38	5.84	0.11	0	0.74
PTSD	12	6.41	1.93	21.22	497.11	97.79	< 0.01
Specific phobia	1	2.4	1	5.6	-	-	-
Separation anxiety disorder	1	4.6	2	10.6	-	-	-
Panic disorder	1	3.1	1.5	6.5	-	-	-
Agoraphobia	1	4.6	1.7	12.5	-	-	-
Study type
Retrospective/cross-sectional	39	2.02	1.21	3.38	3697.48	98.97	< 0.01
Prospective cohort	19	1.29	1.06	1.55	84.03	78.58	< 0.01
Age of bullying
Less than 13 yr	13	1.4	0.58	3.41	123.12	90.25	< 0.01
Older than 13 yr	45	1.81	1.29	2.56	3688.82	98.81	< 0.01
Sex
Male	16	1.84	1.3	2.59	112.23	86.63	< 0.01
Female	15	2.46	1.74	3.48	124.39	88.74	< 0.01
Severity of bullying
Sometimes	7	1.46	1.06	2	43.41	86.18	< 0.01
Frequent	25	2.47	1.94	3.14	122.47	80.4	< 0.01
Geographic location and income level
Low-to-middle income	22	2.41	1.75	3.32	175.97	88.07	< 0.01
High income	36	1.67	1.24	2.25	3441.17	98.98	< 0.01
Depression
Pooling all	92	2.21	1.34	3.65	14525.32	99.37	< 0.01
Major depressive disorder	2	2.27	0.68	7.57	2.07	51.63	0.15
Study type
Retrospective/cross-sectional	63	1.95	1.24	3.07	2594.97	97.61	< 0.01
Prospective cohort	29	3.03	1.31	6.98	4583.05	99.39	< 0.01
Age of bullying
Less than 13 yr	36	2.11	1.63	2.72	544.9	93.58	< 0.01
Older than 13 yr	56	2.29	1.24	4.23	13806.72	99.6	< 0.01
Sex
Male	27	2.07	1.48	2.89	443.84	94.14	< 0.01
Female	21	2.13	1.18	3.86	313.5	93.62	< 0.01
Severity of bullying
Sometimes	15	1.78	1.39	2.28	78.61	82.19	< 0.01
Frequent	28	3.26	2.45	4.34	224.43	87.97	< 0.01
Geographic location and income level
Low-to-middle income	13	2.53	1.75	3.68	143.98	91.67	< 0.01
High income	79	2.15	1.26	3.68	14351.72	99.46	< 0.01
Psychotic symptoms
Specific psychiatric symptoms	6	2.07	1.49	2.87	20.57	75.69	< 0.01
Non-clinical psychotic experiences	9	2.68	2.03	3.54	15.1	47.03	0.06
Psychotic symptoms	5	2.73	1.97	3.77	10.86	63.16	0.03
Personality disorders
Anti-social personality disorder	2	0.58	0.15	2.28	2.53	60.48	0.11
Borderline personality disorder	3	2.2	1.4	3.46	4.8	58.31	0.09
Eating disorders
Bulimia nervosa	1	3	1.4	6.2	-	-	-
Anorexia nervosa	1	0.004	0	251	-	-	-
Non-suicidal self injury
Pooling all	30	1.75	1.4	2.19	749.02	96.13	< 0.01
Study type
Retrospective/cross-sectional	21	1.55	1.09	2.22	721.15	97.23	< 0.01
Prospective cohort	9	1.65	1.34	2.02	19.39	58.75	0.01
Sex
Male	6	4.86	3.35	7.07	13.56	63.12	0.02
Female	4	2.7	2	3.65	8.92	66.37	0.03
Twins	2	2.57	1.79	3.7	0.12	0	0.73
Severity of bullying
Sometimes	6	1.57	1.09	2.25	34.04	85.31	< 0.01
Frequent	7	2.52	1.6	3.97	54.49	88.99	< 0.01
Suicidal ideation
Pooling all	105	1.77	1.56	2.02	2093.5	95.03	< 0.01
Study type
Retrospective/cross-sectional	86	1.8	1.56	2.09	2037.46	95.83	< 0.01
Prospective cohort	19	1.68	1.38	2.05	38.98	53.82	< 0.01
Age of bullying
Less than 13 yr	22	1.85	1.48	2.3	74.4	71.77	< 0.01
Older than 13 yr	83	1.75	1.51	2.03	1984.06	95.87	< 0.01
Sex
Male	21	1.95	1.64	2.32	76.6	73.89	< 0.01
Female	18	2.15	1.84	2.52	33.15	48.72	0.01
Severity of bullying
Sometimes	16	1.53	1.28	1.82	35.19	57.38	< 0.01
Frequent	21	2.59	2.06	3.25	49.83	59.87	< 0.01
Geographic location and income level
Low-to-middle income	11	1.31	1.06	1.61	60.02	83.34	< 0.01
High income	94	1.8	1.43	2.26	1894.91	95.09	< 0.01
Suicide attempt
Pooling all	48	2.13	1.66	2.73	1110.46	95.77	< 0.01
Suicidal attempt/non-suicidal self injury	3	2.97	1.68	5.23	6.33	68.42	0.04
Study type
Retrospective/cross-sectional	40	2.03	1.46	2.84	1105.65	96.47	< 0.01
Prospective cohort	8	2.04	1.38	3.01	4.34	0	0.74
Age of bullying
Less than 13 yr	11	2.11	1.65	2.69	11.49	12.98	0.32
Older than 13 yr	37	1.52	0.82	2.83	579.75	93.79	< 0.01
Sex
Male	7	2.93	1.65	5.18	15.38	54.5	0.02
Female	7	2.89	1.52	5.49	24.23	71.11	< 0.01
Severity of bullying
Sometimes	9	2.19	1.71	2.8	7.52	0	0.48
Frequent	12	3.77	2.55	5.58	28.31	61.14	< 0.01
Geographic location and income level
Low-to-middle income	4	1.91	1.07	3.43	22.18	86.47	< 0.01
High income	44	2.17	1.69	2.8	1084.61	96.04	< 0.01
Behavioural problems
Pooling all	54	1.37	1.18	1.59	862.4	93.85	< 0.01
Study type
Retrospective/cross-sectional	29	1.18	0.99	1.41	311.21	91	< 0.01
Prospective cohort	25	1.56	0.94	2.58	413.53	94.2	< 0.01
Sex
Male	9	1.35	0.68	2.67	450.06	98.22	< 0.01
Female	7	1.99	0.97	4.1	88.07	93.19	< 0.01
Twins	2	1.19	0.94	1.5	7.31	86.31	0.01
Severity of bullying
Sometimes	8	1.95	0.92	4.1	243.71	97.13	< 0.01
Frequent	8	2.26	0.76	6.69	163.51	95.72	< 0.01
Externalising behaviours	20	1.29	1.12	1.5	157.09	87.9	< 0.01
Delinquent/deviant behaviour	24	1.99	1.24	3.2	423.78	94.57	< 0.01
Missed school	7	1.49	0.99	2.23	38.4	84.37	< 0.01
Disruptive behavioural disorders
Attention deficit hyperactivity disorder	1	2.6	0.8	8.5	-	-	-
Oppositional defiant disorder	1	0.8	0.3	2.5	-	-	-
Conduct disorder	1	2.6	0.8	8.8	-	-	-
Other mental health outcomes (not included above)
Nervousness	9	1.82	1.51	2.2	135.59	94.1	< 0.01
Powerlessness	2	1.06	0.95	1.18	1.64	39.18	0.2
Feeling low	7	2.26	1.66	3.08	299.47	98	< 0.01
Irritability or bad temper	7	1.82	1.51	2.2	125.07	95.2	< 0.01
Feel helpless	5	3.2	2.01	5.09	273.51	98.54	< 0.01
Feeling tense	3	3.07	2.06	4.56	3.02	33.75	0.22
Unhappy/sad	12	1.25	0.55	2.84	668.61	98.35	< 0.01
Worried	4	1.27	1.09	1.47	314.35	99.05	< 0.01
Afraid	3	2.68	1.18	6.09	9.49	78.92	0.01