2. Co‐morbid mental disorders or exclusion of co‐morbid mental conditions in trials comparing pharmacotherapy versus placebo or other medication (see also subgroup analyses 'Pharmacotherapy versus placebo (subgrouped by co‐morbidity of participants)').

Trial ID	Experimental treatment group ‐ medication class	Control treatment group ‐ medication class	Co‐morbid mental disorders? Yes/no/ns	Detailed information about co‐morbid diagnoses in participants or exclusion of participants with co‐morbid diagnoses (for studies that do not provide details about co‐morbid conditions)	Detailed information about the exclusion of participants with co‐morbid diagnoses
Kroenke 2006	SNRI	‐	Yes	Major depression, generalised anxiety disorder, social anxiety disorder	People with current/past history of mania, bipolar disorder, schizophrenia, or other psychotic disorder; history of serious or clinically unstable psychiatric condition; known or suspected alcohol or drug abuse within 6 months of screening
Luo 2009	SSRI	‐	Yes	38/80 participants had depression (17 item‐HDRS ≥ 17)	People with co‐exist depressive symptoms occurred prior to pain with HDRS ‐ Total Score ≥ 17
Melzer 2009	NP	‐	No	‐	People with historically known or clinical indication of a psychiatric disorder
Müller 2004	NP	‐	ns	‐	People with co‐morbid depression, drug/alcohol abuse, schizophrenia, or schizo‐affective disorder
Muller 2008	SSRI	‐	Yes	Dysthymia (27.5%); major depressive episode (2.0%); anxiety disorder (panic disorder/agoraphobia/social anxiety disorder/generalised anxiety disorder) (52.9%)	People with somatic symptoms that were judged to be secondary to a psychiatric disorder other than MDS; current or past psychotic disorder; significant suicidal risk
Pilowsky 1990	TCA	‐	ns	‐	People with psychotic illness (including MDS), organic brain syndrome, or alcohol dependence
Volz 2000	TCA	‐	No	‐	People with other significant Axis I diagnoses (e.g. panic disorder, major depressive disorder, substance abuse)
Volz 2002	NP	‐	ns	‐	People with an additional diagnosis of depression, schizophrenia, schizo‐affective disorder, or dementia
Altamura 1991	AP	AP	Yes	Dysthymia (n = 27), anxiety disorder NOS (n = 6)	ns
Aragona 2005	SSRI	NRI	No	‐	People with a diagnosis of another mental disorder
Eberhard 1988	TeCA	TCA	ns	‐	People with major depressive disorder, abuse of drugs, and other psychiatric illnesses
Han 2008b	SSRI	SSRI	ns	‐	People with history of or current (or both) psychotic disorders (such as schizophrenia, schizoaffective disorder, and bipolar disorder); current DSM Axis I disorders that could possibly account for the somatic symptoms (e.g. MDD, anxiety disorders, factitious disorder, malingering, or another somatoform disorder such as somatisation disorder); substance abuse of dependence in the previous 12 months; effect of co‐morbid psychiatric disorders on the effects of the antidepressants cannot be excluded because of the absence of a structured clinical interview, although participants were rigorously evaluated according to DSM‐IV criteria
Huang 2012	SSRI + AP	SSRI	no	‐	People with a diagnosis of another mental disorder (e.g. panic disorder, MDD, or substance abuse)
Jiang 2005	SNRI	TCA	ns	‐	People with drug dependence, severe psychosis, or paranoia
Ju 2003	SNRI	TCA	ns	‐	People with psychotic symptoms, severe brain injury, or substance abuse
Kong 2004	SSRI	TCA	ns	‐	ns
Li 2006	SSRI + AP	SSRI	ns	‐	ns
Ouyang 2006	NaSSA	TCA	Yes	38/80 participants had depression (17 item‐HDRS ≥ 17). No information about other co‐morbidities in the sample was provided	People whose pain was caused by depression, anxiety, or schizophrenia
Sanada 2010	SSRI	SNRI	ns	‐	ns
Wang 2003	SARI	NSAID	Yes	Based on diagnostic criteria in CCMD‐3: depression (n = 46), dysthymia (n = 50), hypochondriasis (n = 20)	Severely depressed, suicidal people
Yang 2006	SNRI	TCA	ns	‐	ns
Ye 2006	NaSSA	TCA	ns	ns	People with any type of drug dependence
Xu 2004	SNRI	TCA	ns	‐	ns
Zhao 2006	NaSSA	TCA	no	‐	People with other mental disorders
Zitman 1991	TCA + AP	TCA	yes	Atypical depression (n = 1), dysthymic disorder (n = 1), panic disorder (n = 1), nicotine abuse (n = 1), tea abuse (n = 1), benzodiazepine abuse (n = 1)	People with a serious psychiatric disease necessitating immediate treatment; or who were alcohol or illicit drug dependent

Anxiety disorder NOS: anxiety disorder not otherwise specified; AP: antipsychotic; CCMD: Chinese Classification of Mental Disorders; SARI: serotonin antagonist and reuptake inhibitor; DSM: Diagnostic and Statistical Manual of Mental Disorders; HDRS: Hamilton Depression Rating Scale; ID: identification; ns: not specified; MDD: major depressive disorder; MDS: major depressive syndrome; n: number; NaSSA: noradrenergic specific serotonergic antidepressant; NP: natural product; NRI: noradrenaline reuptake inhibitor; NSAID: non‐steroidal anti‐inflammatory drug; SNRI: serotonin noradrenaline reuptake inhibitor; SSRI: selective serotonin reuptake inhibitor; TCA: tricyclic antidepressant; TeCA: tetracyclic antidepressant.