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Samuel Ball, PhD

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Professor of Psychiatry


Deputy Dean for Academic Affairs, OAPD

Publications Overview

  • 127 Publications
  • 8,413 Citations
  • 40 Yale Co-Authors



Professor of Psychiatry

Deputy Dean for Academic Affairs, OAPD


I am involved in the coordination of faculty development both within the Department of Psychiatry and in Yale School of Medicine with a focus of working with non-procedural and bridge departments. I have served in several research, education, and clinical leadership positions in the Department of Psychiatry and affiliated non-profit clinical, research, and policy organizations including The APT Foundation, Silver Hill Hospital, and The National Center of Addiction and Substance Abuse. I direct the faculty reappointment and promotion processes in my department and am involved in the development and evaluation of medical school-wide junior faculty mentoring programs. I am a trained mentor and professional coach and consult with junior faculty and departmental leaders on: promotion processes and readiness; incorporation into academic review processes improved assessments of clinical and educational excellence, professionalism, and diversity and inclusion activities, and; consultation on matters related to professional stress, burnout, and impairment. My clinical expertise is the treatment of patients with addiction and co-occurring personality disorders, and I have developed and conducted clinical trials on a specialized psychotherapy for these complex patients and founded a specialized residential treatment program for high functioning professionals (particularly physicians and attorneys) and executives suffering from these disorders. During the COVID-19 pandemic, I developed and directed a 1:1 professional support provider services program for Yale Medicine and Yale New Haven Health healthcare workers and their families.


Education & Training

University of Delaware (1990)
Predoctoral Clinical Psychology Internship
Yale School of Medicine (1990)
University of Delaware, Clinical Psychology (1988)
Colgate University, Psychology English (1984)



My research investigates the most prevalent and yet commonly overlooked type of psychiatric comorbidity – substance abuse and personality disorders. I have conducted a systematic series of studies that have: evaluated the personality dimensions common to both of these psychiatric disorders; identified personality-related subtypes of substance abuse with greater symptom severity and worse prognosis, and; developed and tested the first psychotherapeutic model for the full range of personality disorders found in substance abusers. Personality traits appear to be risk factors for substance use, as well as risk factors for personality disorders that have substance abuse as an important behavioral expression. Maladaptive personality traits and related personality disorders are not simply consequences of addiction. Previous, ongoing, and planned studies focus on two major areas related to personality and substance use disorders: 1) assessment and diagnosis; 2) psychotherapy efficacy.

1) Assessment and Diagnosis
Over half of treated substance abusers meet diagnostic criteria for a personality disorder. The separation of addiction symptoms from personality traits and disorders through careful assessment is critically important for improving diagnostic reliability and validity and predicting treatment response. Personality disorders influence symptom severity, persist and interfere with psychosocial functioning once abstinence is achieved, create significant ongoing risk for relapse, and may require additional specialized treatment.

Over the past 20 years, my research has focused on evaluating extreme, maladaptive personality traits and the prevalence and treatment implications of personality disorders in substance abusers. I have mapped personality dimensions from five factor and seven factor models onto personality disorder diagnoses and compared the reliability of personality disorder and trait dimensions. A constellation of maladaptive personality traits is related to substance dependence severity, polydrug use, earlier age of onset, chronic/heavy use, conduct and antisocial personality disorders, violence, arrests, HIV risk behaviors, psychiatric symptoms, mood disorders, suicide attempts, and early treatment drop-out. My work has emphasized the importance of utilizing dimensional models of personality disorders which incorporate symptom severity measures of diagnostic interview categories as well as self-report measures of maladaptive personality traits and problems.

Consistent with the increased appreciation of the heterogeneity of addicted persons, my research has emphasized that personality factors can be viewed as etiologically or prognostically linked to some, but not necessarily all, subtypes of substance abusers. I have evaluated an empirical framework for understanding the relation between personality dimensions, substance abuse, and personality disorders through a typological system which organizes diverse variables into broader constructs which are associated with different etiologies, patterns, and courses of the disorder. This work included the first extension of a multidimensional alcoholism typology to the drug abuse field. One type (variously called Type I or Type A) is characterized by later age of onset, lower heritability, fewer childhood risk factors, and less severe dependence. The second type (Type II or B) is characterized by earlier onset, higher heritability, more childhood risk factors, more severe dependence, greater psychosocial impairment, antisocial behavior, and psychiatric comorbidity. In a series of studies, I validated this Type A/B and established its connection to certain personality traits and disorders.

Although antisocial and borderline are the most common personality disorders in addiction treatment settings, other disorders (avoidant, paranoid, dependent, narcissistic) affect a significant minority of substance abuse patients, but have not been the focus of diagnostic or treatment research. Other personality disorders, referred to as Cluster A or psychotic spectrum (schizoid, schizotypal, paranoid), are the most common form of diagnostic comorbidity in a group of substance abusers who have had limited or ineffective interactions with the addiction and mental health treatment system (i.e., homeless persons). The development of an effective therapy for the diverse groups of treatment refractory, personality disordered substance abusers has been the focus of my second major area of research and contribution to the field.

2) Psychotherapy Efficacy
Although personality disorders are the most common form of psychiatric comorbidity in drug abusers and convey a negative prognosis, treatments have been adapted or tested for only two specific diagnoses (antisocial and borderline personality disorders). I am the originator of Dual Focus Schema Therapy (DFST) which is the only psychotherapy manual developed and tested for the full range of personality disorders encountered in substance abusers. The problem targets for this treatment are early maladaptive schemas and the associated coping styles related to addictive behaviors. The development of a personality disorder is conceptualized as an interaction between biologically-based personality or temperament traits and highly dysfunctional early caretaking environments which contribute to the development of enduring, unconditional, negative beliefs about oneself, others, and the world and coping behaviors that are inappropriate, rigid, and difficult to change.

DFST is an integrative, cognitive-behavioral therapy that targets these maladaptive personality processes (cognitive, behavioral, interpersonal, emotional) that heighten risk for relapse and adversely impacts treatment engagement, retention, and outcome and the social supports necessary for long-term recovery. It is a manual-guided individual therapy based on a detailed, multi-level assessment and conceptualization of personality traits, problems, and disorders. Cognitive, behavioral, relational, and experiential techniques are selected that focus on reducing addiction and psychiatric symptoms, the intensity of affective and behavioral reactions to schema activation, and maladaptive methods of coping with high risk situations. The choice and staging of interventions is guided by a detailed case formulation of personality functioning and an open, ongoing, collaborative dialogue between the therapist and patient about personality problems, addictive behaviors, and the identification of specific target problems for intervention. This therapeutic partnership fosters the type of strong working alliance that psychotherapy research has found associated with positive outcomes and seems especially important with challenging, refractory patients.

I have completed two smaller and one larger randomized clinical trials comparing DFST to standard addiction counseling approaches. All treatment studies involve very complex, traumatized, multi-problem patients. I have established the feasibility, safety, acceptability, and preliminary efficacy of DFST and developed a: detailed session-by-session treatment manual with prescribed and proscribed techniques; comprehensive, effective training and supervisory procedure for therapists, and; adherence/competence rating system to measure treatment discriminability and fidelity. In the first study in outpatient methadone maintained personality disordered patients, DFST was superior to 12 Step Facilitation Therapy on the primary substance use outcome and secondary therapeutic alliance measure. In the second study in homeless substance abusers with personality disorders, DFST promoted better therapy utilization than a Drug Counseling group. However, homeless clients with more severe forms of certain personality disorders exhibited better Drug Counseling group utilization. The third study of patients in long-term residential treatment found that DFST promoted significant psychiatric, interpersonal, and negative affect symptom reduction over the duration of therapy. However, patients with certain personality disorders had better psychiatric symptom reduction in Individual Drug Counseling than DFST.

The randomized clinical trial of DFST conducted in a homeless drop-in center unexpectedly found rates of Cluster A (paranoid, schizotypal, schizoid) and Cluster C (especially obsessive-compulsive) personality disorders that were 5 – 15 times (i.e., 40 – 75% prevalence rates) more common than typically found in mental health and addiction treatment programs. This was a new finding for the field as previous diagnostic research on the homeless had focused extensively on severe Axis I diagnoses (schizophrenic, mood, and substance use disorders) and ignored the Axis II diagnoses other than antisocial personality disorder. My team completed three additional diagnostic studies, all of which confirm the very high prevalence of these psychotic-spectrum personality disorders among the homeless. This has been the first research to conduct structured diagnostic interviews of the full range of personality disorders among homeless persons while controlling for the effects of other psychiatric disorders. This diagnostic work has established the independence of these very common severe personality disorders from their related, but less prevalent, mood, schizophrenic, anxiety, and substance use disorders. These severely traumatized, psychosocially challenged individuals have been insufficiently served by traditional treatment systems. Other recent research evaluates the relation between maladaptive personality dimensions and addiction symptom severity, psychosocial functioning, relapse risk, treatment motivation and response through a longitudinal evaluation of predictors of outpatient treatment engagement and attrition.

  • Adaptive Brief Interventions for Drop-Out Re-Engagement

Prospective assessment of risk factors for early attrition from substance abuse treatment and evaluation of manual-guided adaptive intervention designed to improve re-engagement in treatment.

  • Psychotic-Spectrum Personality Disorders in Homeless Persons

Evaluates prevalence and correlates of Axis I and II disorders in homeless persons.

Medical Subject Headings (MeSH)

Behavior and Behavior Mechanisms; Ill-Housed Persons; Mental Disorders; Personality; Personality Disorders; Psychiatry; Psychiatry and Psychology; Psychotherapy; Substance Abuse Detection; Treatment Outcome

Research at a Glance

Yale Co-Authors

Frequent collaborators of Samuel Ball's published research.






Academic Achievements and Community Involvement

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    Committee Member

Clinical Care


Clinical Specialties

Psychiatry; Addiction Medicine; Psychology

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  • Yale Department of Psychiatry

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Dec 202412Thursday