Transcranial Direct Current Stimulation and Chronic Pain

Inclusion Criteria: * Age: 18-79 years old * Gender: Any * Ethnicity: Any * Chronic pain (\> 3-months); No current use of nonprescription opioids (\< 1 month); Able and willing to comply with scheduled visits and other study-related procedures to complete the study; Willing and able to give informed consent. Exclusion Criteria: * Diagnosis (as defined by DSM-IV) of: any psychotic disorder (lifetime); eating disorder (current or within the past year); obsessive compulsive disorder (lifetime)); mental retardation. * History of drug or alcohol abuse or dependence (as per DSM-IV criteria) within the last 3 months (except nicotine and caffeine). * Subject is on regular benzodiazepine medication which it is not clinically appropriate to discontinue. * Subject requires a rapid clinical response due to inanition, psychosis or high suicide risk. * Neurological disorder or insult, e.g., recent stroke (CVA), which places subject at risk of seizure or neuronal damage with tDCS. * Subject has metal in the cranium, skull defects, or skin lesions on scalp (cuts, abrasions, rash) at proposed electrode sites. * Female subject who is pregnant. * Participants who are not fluent in English will not be included in the trial for safety reasons: a) It is usually not possible to have an interpreter reliably available every weekday for up to 4 weeks and it is not safe to give tDCS to a subject who cannot tell us immediately of any side effects; Note that translation of the proposed ACT activity into English has not been validated and that we cannot be confident that they would be accurately translated and validated. * Minors * Older than 79 years old * last use \>24 months * history of EEG or any electrical implant (i.e. pacemaker) * history of Parkinson's, diagnosis of bipolar, schizophrenia/schizo-affective d/o, OCD, epilepsy, alzheimers * taking antipsychotic drugs