Psychotherapy is a treatment that involves a talking relationship between a therapist and patient.  There are many forms of psychotherapy like cognitive Behavioral psychotherapy, psychodynamic (psychoanalytic) psychotherapy, family therapy,  marital Therapy, cognitive Analytical Therapy (CAT), Interpersonal Therapy (IPT) and Counselling.

Psychologist has a degree in clinical psychology, and treats psychiatric disorders and emotional difficulties  with psychotherapy.

Some psychologist are trained in doing  psychological testing and  psychometric assessments including Educational Assessment (Testing for Intellectual Difficulties like IQ test..), testing for  Attention Deficit Hyperactivity Disorder (ADHD), Screening and assessment of  Autism Spectrum Disorders (ASD), Personality assessments and others.